ASM.TXT

@Assembler Programming Topics
:8086 architecture
^Intel 8086 Family Architecture

%	General Purpose Registers		Segment Registers

	AH/AL  AX  (EAX)  Accumulator		 CS	Code Segment
	BH/BL  BX  (EBX)  Base			 DS	Data Segment
	CH/CL  CX  (ECX)  Counter		 SS	Stack Segment
	DH/DL  DX  (EDX)  Data			 ES	Extra Segment
						(FS)	386 and newer
	(Exx) indicates 386+ 32 bit register 	(GS)	386 and newer


%	Pointer Registers			Stack Registers

	SI (ESI)  Source Index			SP (ESP)  Stack Pointer
	DI (EDI)  Destination Index		BP (EBP)  Base Pointer
	IP	  Instruction Pointer

%	Status Registers

	FLAGS Status Flags   (see ~FLAGS~)

%	Special Registers (386+ only)

	CR0	Control Register 0	  DR0	 Debug Register 0
	CR2	Control Register 2	  DR1	 Debug Register 1
	CR3	Control Register 3	  DR2	 Debug Register 2
					  DR3	 Debug Register 3
	TR4	Test Register 4		  DR6	 Debug Register 6
	TR5	Test Register 5		  DR7	 Debug Register 7
	TR6	Test Register 6
	TR7	Test Register 7
	
%	Register	  Default Segment    Valid Overrides

	BP			SS		DS, ES, CS
	SI or DI		DS		ES, SS, CS
	DI strings		ES		None
	SI strings		DS		ES, SS, CS


	- see  ~CPU~   ~DETECTING~  ~Instruction Timing~

:Instruction Timing
^Instruction Clock Cycle Calculation


	Some instructions require additional clock cycles due to a "Next
	Instruction Component" identified by a "+m" in the instruction
	clock cycle listings.  This is due to the prefetch queue being
	purge on a control transfers.	Below is the general rule for
	calculating "m":


	88/86 not applicable
	286  "m" is the number of bytes in the next instruction
	386  "m" is the number of components in the next instruction
		(the instruction coding (each byte), plus the data and
		the displacement are all considered components)


^8088/8086  Effective Address (EA) Calculation

%		   Description				  Clock Cycles

	Displacement						6
	Base or Index (BX,BP,SI,DI)				5
	Displacement+(Base or Index)				9
	Base+Index (BP+DI,BX+SI)				7
	Base+Index (BP+SI,BX+DI)				8
	Base+Index+Displacement (BP+DI,BX+SI)		       11
	Base+Index+Displacement (BP+SI+disp,BX+DI+disp)	       12


	- add 4 cycles for word operands at odd addresses
	- add 2 cycles for segment override
	- 80188/80186 timings differ from those of the 8088/8086/80286


%	Task State Calculation

	"TS" is defined as switching from VM/486 or 80286 TSS to one of
	the following:

 			ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ¿
			³	        New Task		³
			ÃÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄ´
	ÚÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´486 TSS³486 TSS³386 TSS³386 TSS³286 TSS³
	³   Old Task	³ (VM=0)³ (VM=1)³ (VM=0)³ (VM=1)³	³
	ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄ´
	386 TSS (VM=0)	³	³	³  309  ³  226  ³  282  ³
			ÃÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄ´
	386 TSS (VM=1)	³	³	³  314  ³  231  ³  287  ³
			ÃÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄ´
	386 CPU/286 TSS	³	³	³  307  ³  224  ³  280  ³
			ÃÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄ´
	486 CPU/286 TSS	³  199	³  177	³	³	³  180	³
			ÀÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÙ

		       	     
%	Miscellaneous

	- all timings are for best case and do not take into account wait
	  states, instruction alignment, the state of the prefetch queue,
	  DMA refresh cycles, cache hits/misses or exception processing.
	- to convert clocks to nanoseconds divide one microsecond by the
	  processor speed in MegaHertz:
   
^(1000MHz/(n MHz)) = X nanoseconds


	- see	~8086 Architecture~

:directives:asm directives
^Macro Assembler Directives

^Processor Code Generation Directives

	.186	enables assembly of 80186 instructions
	.286	enables assembly of non privileged 80286 instructions
	.286C	same as .286
	.286P	enables assembly of all 80286 instructions
	.287	enabled assembly of 80287 instructions
	.386	enabled assembly of non privileged 80386 instructions
		If used before .MODEL segments are defined as 32bits.
		Causes all segments to default to DWORD alignment.
	.386P	enabled assembly of all 80386 instructions (see .386)
	.387	enabled assembly of 80387 instructions
	.8086	default, enables assembly of 8088/8086 instruction
	.8087	default, enables assembly of 8087 instructions


	These directives must precede the segment they are to effect.
	they cannot occur within a segment.


^Memory Model Directives

	.CODE  [name]	starts code segment; must follow .MODEL directive
	.CONST		starts a constant data segment with name CONST;
			must follow .MODEL directive; placed in DGROUP
	.DATA		starts a near data segment for initialized data
			with name _DATA; must follow .MODEL directive;
			placed in DGROUP
	.DATA?		starts a near data segment for uninitialized
			data with name _BSS; must follow .MODEL
			directive; placed in DGROUP
	.FARDATA [name]	not placed in any group
	.FARDATA? [name] not placed in any group
	.MODEL model	defines memory model to be one of the following:
			SMALL, COMPACT, MEDIUM, LARGE or HUGE;	must be
			used prior to any other segment directive
	.STACK [size]	indicates start of stack segment named 'STACK'
			with size indicating number of bytes to reserve,
			default is 1k; placed in DGROUP


^Segment Definition, Segment Ordering and Linkage Directives

	.ALPHA		orders segments alphabetically
	.SEQ		orders segments sequentially (default)
	ASSUME sreg:name [,sreg:name...]   selects default segment
			register to be used by the assembler, not the CPU,
			for addressing all symbols in the segment or group.
			Name must be associated with a SEGMENT or GROUP
			or set to "NOTHING" to indicate no segment register
			is to be associated.
	COMM def [,def...]  defines variables that are both public and
			external (communal).  Can be used in and include
			file to identify it to each source file without
			declaring it in each model as extern.  Actually
			defines data once.  Communal variables cannot be
			initialized, and are not guaranteed to be allocated
			contiguously since these are allocated by the linker.
	DOSSEG		orders segments the same as DOS.  This is Microsoft
			languages default order; causes paragph alignment
	END [name]	marks end of source module and sets program
			start address (CS:IP) if 'name' is present
   name ENDP		ends procedure 'name'
   name ENDS		ends a segment or structure
	EXTRN name:type [,name:type...]  defines one or more external symbols
   name GROUP seg[,seg]
   name LABEL [NEAR|FAR|PROC]  defines an entry point;	If PROC is specified,
			it's value depends on the current MODEL
	NAME pgmName	ignored since MASM 5.0; used to set module name
   name PROC [NEAR|FAR]	defines procedure; NEAR/FAR has .MODEL default
	PUBLIC name[,name...]  makes symbol 'name' available to other modules
   name SEGMENT [align][combine][use]['class']
		align	= BYTE	align on byte address (no alignment)
			= WORD	align on even address
			= DWORD	align on DWORD address
			= PARA	align on next 16 byte paragraph
			= PAGE	align on next 256 byte boundary
		combine = PUBLIC  similar named segments are concatenated (CS)
			= STACK   similar named segments are concatenated (SS)
			= COMMON  similar named segment are overlapped
			= MEMORY  similar names segments are concatenated
			= AT addr segment relative to absolute address
			= nothing segment is private and loaded independent
		use	= USE16   segments will be 16 bits (if .386)
			= USE32   segments will be 32 bits (if .386)


^Data Allocation Directives

	ALIGN n		aligns next variable or instruction on a boundary
			that is a multiple of "n".  This can speed memory
			fetches on 16 and 32 bit CPU'S if aligned.  New to
			~MASM~ 5.0, previous versions used EVEN.  Can result
			in NOP's added to code.
 [name]	DB init[,init...]  define byte
 [name]	DD init[,init...]  define double word (DWORD, 4 bytes)
 [name]	DF init[,init...]  define far word (FWORD, 386, 6 bytes)
 [name]	DQ init[,init...]  define quad word (QWORD, 8 bytes)
 [name]	DT init[,init...]  define temp word (TBYTE, 10 bytes)
 [name]	DW init[,init...]  define word (WORD, 2 bytes)
  count	DUP (init[,init...]) duplicate 'init' 'count' times; DUP can be
			nested to 17 levels; DUP'ed initial values
			of (?) don't result in data in the object file
			but instead increment the next data addr
   name	ENDS		end of structure or segment
	EVEN		same as align 2;  Aligns data on even boundary
	ORG expr	sets location counter to 'expr';  If 'expr'
			is '$' the code is ORG'ed at the current loc.
   name	RECORD fld[,fld...]  defines a byte or word variable
			consisting of bit fields;  fields have the format:
			fieldname:width[=expr];  the sum of all widths
			must be <= 0
 [name]	STRUC <[init[,init]]>  defines beginning of a structure; Values
 			between <> are initializers;  The '<>' symbols
			are required.


^Logical and Bit Oriented Directives

  expr1	AND  expr2	returns nonzero if any set bit matches
  expr1	EQ   expr2	returns (-1) for true or (0) for false
  expr1	GE   expr2	returns (-1) for true or (0) for false
  expr1	LE   expr2	returns (-1) for true or (0) for false
  expr1	LT   expr2	returns (-1) for true or (0) for false
	MASK {fldname|record}  returns bit mask for bits in record
  expr1	OR   expr2	returns bitwise OR on expr1 and expr2
	NOT  expr	returns 'expr' with all bits reversed
   expr	SHL  count	returns expr shifted left count times
   expr	SHR  count	returns expr shifted right count times
	WIDTH {fldname|record}	returns width of field in bit record
  expr1 XOR expr2	returns bitwise XOR on expr1 and expr2


^Other Operators and Directives

	[]		index operator, same as addition
	.MSFLOAT	encode floats in Microsoft Real Format
	.TYPE	expr	returns byte defining mode and scope of expr
   name	EQU 	expr	assigns expression to name. surround text with <>
	HIGH	expr	returns high byte of 'expr'
	INCLUDE filespec  inserts code from 'filespec' into file
	INCLUDELIB filespec  stores link library info in .OBJ file
	LENGTH	var	returns number of data objects in DUPed 'var'
	LOW	expr	returns low byte of 'expr'
  expr1	MOD	expr2	return remainder of expr1/expr2
	OFFSET	expr	returns offset of expr;   When .MODEL is used
			the offset of a group relative segment refers
			to the end of the segment
   type	PTR	expr	forces 'expr' to 'type'
	SEG	expr	returns segment of expression
	SHORT		sets type of label to short, less than 128
			bytes from start of next instruction
	SIZE	var	returns # of bytes allocated by DUP directive
	THIS	type	returns an operand of specified type whose
			offset and segment values are equal to the
			current location
	TYPE	expr	returns type of expression


%	Program Listing and Documentation Directives

	.CREF		restores listing of cross reference symbols
	.LALL		include macro expansion in listings
	.LFCOND		include false conditional blocks in listings
	.LIST		starts listing of statements
	.SALL		suppress listing of all macro expansions
	.SFCOND		suppress false conditional blocks in listings
	.XALL		start listing of macro expansion
	.XCREF [name[,name...]]  suppress symbols in cross reference
	.XLIST		suppress program listing
	COMMENT delimiter [text]
	PAGE   [[len],wid]	sets page length&width or ejects if no parms
	SUBTTL	text	defines program listing subtitle
	TITLE	text	defines program listing title


%	Condition Assembly Directives

	ELSE		else clause for conditional assembly block
	ENDIF		terminates a conditional assembly block
	IFDEF	name	conditional assembly if name is defined


%	Macro Definition Directives

	ENDM		terminates a macro block
	EXITM		exit macro expansion immediately
	IRP  parm,<arg[,arg...]> parm in the statements enclosed by the
			IRP and ENDM will be repeated and replaced with the
			values of "arg" for each "arg" in the <>.
	IRPC parm,<string>  parm in the statements enclosed by the IRPC
			and ENDM will be repeated and replaced with the values
			of each char in the "string" for each character
			position in the string.  "string" should be enclosed
			in <> if it contains spaces or other separators.
	LOCAL name[,name...]  defines scope symbol as local to a macro
   name	MACRO [parm[,parm...]]	defines a macro and it's parameters
	PURGE name[,name]  purges macros from memory
	REPT	expr	repeats all statements through ENDM statement for
			'expr' times


%	User Message Directives

	.ERR		generates and error
	.ERR1		generates an error on PASS 1
	.ERR2		generates an error on PASS 2
	.ERRB	<arg>	generates an error if 'arg' is blank
	.ERRDEF name	generates an error if 'name' is previously defined
	.ERRDIF[I] <arg1>,<arg2>
	.ERRE	expr	generates and error is 'expr' is false
	%OUT	text	displays 'text' to console


%	Predefined Equates (available only if simplified segments are used)

	@curseg		contains the current segment
	@filename	current file name without extension
	@code		contains the current code segment
	@codesize	0 for small & compact, 1 for large, medium & huge
	@datasize	0 for small & medium, 1 for compact & large, 2=huge
	@const		contains segment of define by .CONST
	@data		contains segment of define by .DATA
	@data?		contains segment of define by .DATA?
	@fardata	contains segment of define by .FARDATA
	@fardata?	contains segment of define by .FARDATA?
	@stack		contains segment of define by .STACK

	Most of these are only available if the simplified segment system
	is used.  @curseg and @filename are available regardless.


%	Radix Specifiers

	.RADIX expr	sets radix [2..16] for numbers (dec. default)
	B		binary data specifier
	Q		octal data specifier
	O		octal data specifier
	D		decimal data specifier
	H		hexadecimal data specifier


:masm options:assembler options
^Microsoft Assembler Command Line Options

^MASM [options] srcfile[,[objfile][,[lstfile][,[xreffile]]]][;]

%	Options 		Definition
	/A		generate segments in alphabetical order
	/B[size]    	sets I/O buffer size in K bytes (1..63, default 32)
	/C		generate cross reference file with .CRF extension
	/D		generate PASS 1 listing
	/Dsym[=val]	define symbol for use during assembly
	/E		emulate floating point instructions (for use with HLL)
	/H		list options and command syntax
	/Ipath		include-file search path
	/L		generate listing file with .LST extension
	/ML		case sensitive for all symbols
	/MU		upper case all symbols (default)
	/MX		case sensitive in external and public symbols
	/N		suppress symbol tables in listings
	/P		check for impure code in 286 and 386 protected
			mode (invalid CS overrides)
	/S		generate segments in the order they are found (default)
	/T		terse message display; display errors only
	/V		verbose message display; includes # lines and symbols
	/W{0|1|2}	assembly warning level
			    0 = no warnings
			    1 = severe warnings only
			    2 = all warnings enabled
	/X		display complete conditional assembly blocks in
			listing including false conditionals
	/Z		display errors including line numbers to screen
	/ZD		generate line numbers in .OBJ files
	/ZI		generate both symbolic and line number information in
			.OBJ files

%	Environment Variables

	INCLUDE		search path for include files
	MASM		default command line options
:flags register:8086 flags
^FLAGS - Intel 8086 Family Flags Register

      ³11³10³F³E³D³C³B³A³9³8³7³6³5³4³3³2³1³0³
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  CF Carry Flag
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  1
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  PF Parity Flag
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  0
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  AF Auxiliary Flag
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  0
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  ZF Zero Flag
	³  ³ ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  SF Sign Flag
	³  ³ ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  TF Trap Flag  (Single Step)
	³  ³ ³ ³ ³ ³ ³ ³ ÀÄÄÄ  IF Interrupt Flag
	³  ³ ³ ³ ³ ³ ³ ÀÄÄÄ  DF Direction Flag
	³  ³ ³ ³ ³ ³ ÀÄÄÄ  OF Overflow flag
	³  ³ ³ ³ ÀÄÁÄÄÄ  IOPL I/O Privilege Level  (286+ only)
	³  ³ ³ ÀÄÄÄÄÄ  NT Nested Task Flag  (286+ only)
	³  ³ ÀÄÄÄÄÄ  0
	³  ÀÄÄÄÄÄ  RF Resume Flag (386+ only)
	ÀÄÄÄÄÄÄ  VM  Virtual Mode Flag (386+ only)

	- see	~PUSHF~  ~POPF~  ~STI~  ~CLI~  ~STD~  ~CLD~
:models:segment names
^Memory Model Programming & Segment Information

%	Model
	TINY	Data and code fit in one 64K segment.  All code and
		data are accessed via near pointers.
	SMALL	64k data segment max and 64k code segment max.	All
		code and data are accessed via near pointers.
	COMPACT	1Mb data segment max and 64K code segment max.	Code
		is accessed via near pointers, data is accessed via
		far pointers.  No array can be greater than 64K
	MEDIUM	64K data segment max and 1Mb code segment max.	Code is
		accessed via far pointers, data is accessed via	near pointers.
	LARGE	1Mb data segment max and 1Mb code segment max.	All
		code and data are accessed via far pointers.  No
		single element can be greater than 64K.
	HUGE	1Mb data segment max and 1Mb code segment max.	All
		code and data are accessed via far pointers.  This is
		the only model where arrays can be larger than 64K.
		In this mode is C will normalize all data pointers
		to avoid segment wrapping.

^Small Memory Model

%	Directive  Segment    Alignment    Combine	Class
	.CODE	    _TEXT	WORD	    PUBLIC	'CODE'
	.DATA	    _DATA	WORD	    PUBLIC	'DATA'
	.CONST	    CONST	WORD	    PUBLIC	'CONST'
	.DATA?	    _BSS	WORD	    PUBLIC	'BSS'
	.STACK	    STACK	PARA	    STACK	'STACK'


^Compact Memory Model

%	Directive   Segment    Alignment    Combine	Class
	.CODE	    _TEXT	WORD	    PUBLIC	'CODE'
	.FARDATA    FAR_DATA	PARA	    private	'FAR_DATA'
	.FARDATA?   FAR_BSS	PARA	    private	'FAR_BSS'
	.DATA	    _DATA	WORD	    PUBLIC	'DATA'
	.CONST	    CONST	WORD	    PUBLIC	'CONST'
	.DATA?	    _BSS	WORD	    PUBLIC	'BSS'
	.STACK	    STACK	PARA	    STACK	'STACK'


^Medium Memory Model

%	Directive  Segment    Alignment	    Combine	Class
	.CODE	  name_TEXT	WORD	    PUBLIC	'CODE'
	.DATA	    _DATA	WORD	    PUBLIC	'DATA'
	.CONST	    CONST	WORD	    PUBLIC	'CONST'
	.DATA?	    _BSS	WORD	    PUBLIC	'BSS'
	.STACK	    STACK	PARA	    STACK	'STACK'


^Large or Huge Memory Models

%	Directive    Segment  Alignment	    Combine	Class
	.CODE	    name_TEXT	WORD	    PUBLIC	'CODE'
	.FARDATA    FAR_DATA	PARA	    private	'FAR_DATA'
	.FARDATA?   FAR_BSS	PARA	    private	'FAR_BSS'
	.DATA	     _DATA	WORD	    PUBLIC	'DATA'
	.CONST	     CONST	WORD	    PUBLIC	'CONST'
	.DATA?	     _BSS	WORD	    PUBLIC	'BSS'
	.STACK	     STACK	PARA	    STACK	'STACK'


	- all segments fall into DGROUP except for ???_TEXT, FAR_DATA
	  and FAR_BSS
	- see ~ASM DIRECTIVES~
:msw:machine status word
^MSW - Machine Status Word (286+ only)


      ³31³30-5³4³3³2³1³0³  Machine Status Word
	³   ³  ³ ³ ³ ³ ÀÄÄÄÄ Protection Enable (PE)
	³   ³  ³ ³ ³ ÀÄÄÄÄÄ Math Present (MP)
	³   ³  ³ ³ ÀÄÄÄÄÄÄ Emulation (EM)
	³   ³  ³ ÀÄÄÄÄÄÄÄ Task Switched (TS)
	³   ³  ÀÄÄÄÄÄÄÄÄ Extension Type (ET)
	³   ÀÄÄÄÄÄÄÄÄÄÄ Reserved
	ÀÄÄÄÄÄÄÄÄÄÄÄÄÄ Paging (PG)


	Bit 0	PE	Protection Enable, switches processor between
			protected and real mode
	Bit 1	MP	Math Present, controls function of the ~WAIT~
			instruction
	Bit 2	EM	Emulation, indicates whether coprocessor functions
			are to be emulated
	Bit 3	TS	Task Switched, set and interrogated by coprocessor
			on task switches and when interpretting coprocessor
			instructions
	Bit 4	ET	Extension Type, indicates type of coprocessor in
			system
	Bits 5-30	Reserved
	bit 31	PG	Paging, indicates whether the processor uses page
			tables to translate linear addresses to physical
			addresses

	- see	~SMSW~  ~LMSW~
:aaa
^AAA - Ascii Adjust for Addition


	Usage:	AAA
	Modifies flags: AF CF (OF,PF,SF,ZF undefined)


	Changes contents of AL to valid unpacked decimal.  The high order
	nibble is zeroed.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  8	3     4	    3		  1


	- see ~Instruction Timing~

:aad
^AAD - Ascii Adjust for Division


	Usage:	AAD
	Modifies flags: SF ZF PF (AF,CF,OF undefined)


	Used before dividing unpacked decimal numbers.	 Multiplies AH by
	10 and the adds result into AL.  Sets AH to zero.  This instruction
	is also known to have an undocumented behavior.



%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  60	14    19    14		  2

	- see ~Instruction Timing~

:aam
^AAM - Ascii Adjust for Multiplication


	Usage:	AAM
	Modifies flags: PF SF ZF (AF,CF,OF undefined)


	Used after multiplication of two unpacked decimal numbers, this
	instruction adjusts an unpacked decimal number.  The high order
	nibble of each byte must be zeroed before using this instruction.
	This instruction is also known to have an undocumented behavior.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  83	16    17    15		  2


	- see ~Instruction Timing~

:aas
^AAS - Ascii Adjust for Subtraction


	Usage:	AAS
	Modifies flags: AF CF (OF,PF,SF,ZF undefined)


	Corrects result of a previous unpacked decimal subtraction in AL.
	High order nibble is zeroed.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  8	3     4	    3		  1


	- see ~Instruction Timing~

:adc
^ADC - Add With Carry

	Usage:	ADC	dest,src
	Modifies flags: AF CF OF SF PF ZF


	Sums two binary operands placing the result in the destination.
	If CF is set, a 1 is added to the destination.


%				Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	16+EA	7     7	    3		 2-4  (W88=24+EA)
	reg,mem 	 9+EA	7     6	    2		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem,immed	17+EA	7     7	    3		 3-6  (W88=23+EA)
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:add
^ADD - Arithmetic Addition

	Usage:	ADD	dest,src
	Modifies flags: AF CF OF PF SF ZF


	Adds "src" to "dest" and replacing the original contents of "dest".
	Both operands are binary.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	16+EA	7     7	    3		 2-4  (W88=24+EA)
	reg,mem 	 9+EA	7     6	    2		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem,immed	17+EA	7     7	    3		 3-6  (W88=23+EA)
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:and
^AND - Logical And

	Usage:	AND	dest,src
	Modifies flags: CF OF PF SF ZF (AF undefined)


	Performs a logical AND of the two operands replacing the destination
	with the result.


%				Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	16+EA	7     7	    3		 2-4  (W88=24+EA)
	reg,mem 	 9+EA	7     6	    1		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem,immed	17+EA	7     7	    3		 3-6  (W88=23+EA)
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:arpl
^ARPL - Adjusted Requested Privilege Level of Selector
^(286+ protected mode)


	Usage:	ARPL	dest,src
	Modifies flags: ZF


	Compares the RPL bits of "dest" against "src".	If the RPL bits
	of "dest" are less than "src", the destination RPL bits are set
	equal to the source RPL bits and the Zero Flag is set.	Otherwise
	the Zero Flag is cleared.


%				Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  -	10    20    9		  2
	mem,reg 	  -	11    21    9		  4


	- see ~Instruction Timing~

:bound
^BOUND - Array Index Bound Check (80188+)


	Usage:	BOUND	src,limit
	Modifies flags: None


	Array index in source register is checked against upper and lower
	bounds in memory source.  The first word located at "limit" is
	the lower boundary and the word at "limit+2" is the upper array bound.
	Interrupt 5 occurs if the source value is less than or higher than
	the source.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,mem32	  -   nj=13 nj=10   7		  2
	reg32,mem64	  -   nj=13 nj=10   7		  2

	- nj = no jump taken
	- see ~Instruction Timing~

:bsf
^BSF - Bit Scan Forward (386+ only)


	Usage:	BSF	dest,src
	Modifies flags: ZF


	Scans source operand for first bit set.  Sets ZF if a bit is found
	set and loads the destination with an index to first set bit.  Clears
	ZF is no bits are found set.  BSF scans forward across bit pattern
	(0-n) while BSR scans in reverse (n-0).


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  -	-   10+3n  6-42		  3
	reg,mem 	  -	-   10+3n  7-43		 3-7
	reg32,reg32	  -	-   10+3n  6-42		 3-7
	reg32,mem32	  -	-   10+3n  7-43		 3-7


	- see ~Instruction Timing~

:bsr
^BSR - Bit Scan Reverse  (386+ only)


	Usage:	BSR	dest,src
	Modifies flags: ZF


	Scans source operand for first bit set.  Sets ZF if a bit is found
	set and loads the destination with an index to first set bit.  Clears
	ZF is no bits are found set.  BSF scans forward across bit pattern
	(0-n) while BSR scans in reverse (n-0).


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  -	-   10+3n  6-103	  3
	reg,mem 	  -	-   10+3n  7-104	 3-7
	reg32,reg32	  -	-   10+3n  6-103	 3-7
	reg32,mem32	  -	-   10+3n  7-104	 3-7


	- see ~Instruction Timing~

:bswap
^BSWAP - Byte Swap (486+ only)


	Usage:	BSWAP	reg32
	Modifies flags: none


	Changes the byte order of a 32 bit register from big endian to
	little endian or vice versa.   Result left in destination register
	is undefined if the operand is a 16 bit register.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg32	 	  -	-     -     1	  	  2


	- see ~Instruction Timing~

:bt
^BT - Bit Test	(386+ only)


	Usage:	BT	dest,src
	Modifies flags: CF


	The destination bit indexed by the source value is copied into the
	Carry Flag.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,immed8	  -	-     3	    3		 4-8
	mem16,immed8	  -	-     6	    6		 4-8
	reg16,reg16	  -	-     3	    3		 3-7
	mem16,reg16	  -	-     12    12		 3-7


	- see ~Instruction Timing~

:btc
^BTC - Bit Test with Compliment  (386+ only)


	Usage:	BTC	dest,src
	Modifies flags: CF


	The destination bit indexed by the source value is copied into the
	Carry Flag after being complimented (inverted).


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,immed8	  -	-     6	    6		 4-8
	mem16,immed8	  -	-     8	    8		 4-8
	reg16,reg16	  -	-     6	    6		 3-7
	mem16,reg16	  -	-     13    13		 3-7


	- see ~Instruction Timing~

:btr
^BTR - Bit Test with Reset  (386+ only)


	Usage:	BTR	dest,src
	Modifies flags: CF


	The destination bit indexed by the source value is copied into the
	Carry Flag and then cleared in the destination.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,immed8	  -	-     6	    6		 4-8
	mem16,immed8	  -	-     8	    8		 4-8
	reg16,reg16	  -	-     6	    6		 3-7
	mem16,reg16	  -	-     13    13		 3-7


	- see ~Instruction Timing~

:bts
^BTS - Bit Test and Set  (386+ only)


	Usage:	BTS	dest,src
	Modifies flags: CF


	The destination bit indexed by the source value is copied into the
	Carry Flag and then set in the destination.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,immed8	  -	-     6	    6		 4-8
	mem16,immed8	  -	-     8	    8		 4-8
	reg16,reg16	  -	-     6	    6		 3-7
	mem16,reg16	  -	-     13    13		 3-7


	- see ~Instruction Timing~

:call
^CALL - Procedure Call

	Usage:	CALL	destination
	Modifies flags: None

	Pushes Instruction Pointer (and Code Segment for far calls) onto
	stack and loads Instruction Pointer with the address of proc-name.
	Code continues with execution at CS:IP.

%						         Clocks
%		   Operands			808x   286     386     486

	rel16 (near, IP relative)		 19     7      7+m      3
	rel32 (near, IP relative)		 -	-      7+m      3

	reg16 (near, register indirect)		 16     7      7+m      5
	reg32 (near, register indirect)		 -	-      7+m      5

	mem16 (near, memory indirect)		 -     21+EA    11    10+m      5
	mem32 (near, memory indirect)		 -   	-     10+m      5

	ptr16:16 (far, full ptr supplied)	 28     13    17+m      18
	ptr16:32 (far, full ptr supplied)	 -	-     17+m      18
	ptr16:16 (far, ptr supplied, prot. mode) -	26    34+m      20
	ptr16:32 (far, ptr supplied, prot. mode) -	-     34+m      20
	m16:16 (far, indirect)		       37+EA    16    22+m      17
	m16:32 (far, indirect)			 -	-     22+m      17
	m16:16 (far, indirect, prot. mode)	 -      29    38+m      20
	m16:32 (far, indirect, prot. mode)	 -	-     38+m      20

	ptr16:16 (task, via TSS or task gate)	 -     177     TS     37+TS
	m16:16 (task, via TSS or task gate)	 -   180/185  5+TS    37+TS
	m16:32 (task)				 -	-      TS     37+TS
	m16:32 (task)				 -	-     5+TS    37+TS

	ptr16:16 (gate, same privilege)		 -      41    52+m      35
	ptr16:32 (gate, same privilege)		 -	-     52+m      35
	m16:16 (gate, same privilege)	       	 -	44    56+m      35
	m16:32 (gate, same privilege)		 -	-     56+m      35

	ptr16:16 (gate, more priv, no parm)	 -   	82    86+m      69
	ptr16:32 (gate, more priv, no parm)	 -	-     86+m      69
	m16:16 (gate, more priv, no parm)	 -   	83    90+m      69
	m16:32 (gate, more priv, no parm)	 -	-     90+m      69

	ptr16:16 (gate, more priv, x parms)	 -    86+4x  94+4x+m  77+4x
	ptr16:32 (gate, more priv, x parms)	 -	-    94+4x+m  77+4x
	m16:16 (gate, more priv, x parms)	 -    90+4x  98+4x+m  77+4x
	m16:32 (gate, more priv, x parms)	 -	-    98+4x+m  77+4x


	- see ~Instruction Timing~

:cbw
^CBW - Convert Byte to Word


	Usage:	CBW
	Modifies flags: None


	Converts byte in AL to word Value in AX by extending sign of AL
	throughout register AH.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     3	    3		  1


	- see ~Instruction Timing~

:cdq
^CDQ - Convert Double to Quad	(386+ only)


	Usage:	CDQ
	Modifies flags: None


	Converts signed DWORD in EAX to a signed quad word in EDX:EAX by
	extending the high order bit of EAX throughout EDX


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  -	-     2	    3		  1


	- see ~Instruction Timing~

:clc
^CLC - Clear Carry


	Usage:	CLC
	Modifies flags: CF


	Clears the Carry Flag.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2	    2		  1


	- see ~Instruction Timing~

:cld
^CLD - Clear Direction Flag


	Usage:	CLD
	Modifies flags: DF


	Clears the Direction Flag causing string instructions to increment
	the SI and DI index registers.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2	    2		  1


	- see ~Instruction Timing~

:cli
^CLI - Clear Interrupt Flag (disable)


	Usage:	CLI
	Modifies flags: IF


	Disables the maskable hardware interrupts by clearing the Interrupt
	flag.  NMI's and software interrupts are not inhibited.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     3	    5		  1


	- see ~Instruction Timing~

:clts
^CLTS - Clear Task Switched Flag  (286+ privileged)


	Usage:	CLTS
	Modifies flags: None


	Clears the Task Switched Flag in the Machine Status Register.  This
	is a privileged operation and is generally used only by operating
	system code.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  -	2     5	    7		  2


	- see ~Instruction Timing~

:cmc
^CMC - Complement Carry Flag


	Usage:	CMC
	Modifies flags: CF


	Toggles (inverts) the Carry Flag


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2	    2		  1


	- see ~Instruction Timing~

:cmp
^CMP - Compare

	Usage:	CMP	dest,src
	Modifies flags: AF CF OF PF SF ZF


	Subtracts source from destination and updates the flags but does
	not save result.  Flags can subsequently be checked for conditions.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	 9+EA	7     5	    2		 2-4  (W88=13+EA)
	reg,mem 	 9+EA	6     6	    2		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem,immed	10+EA	6     5	    2		 3-6  (W88=14+EA)
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:cmps:cmpsb:cmpsw:cmpsd
^CMPS - Compare String (Byte, Word or Doubleword)

	Usage:	CMPS	dest,src
		CMPSB
		CMPSW
		CMPSD	(386+ only)
	Modifies flags: AF CF OF PF SF ZF

	Subtracts destination value from source without saving results.
	Updates flags based on the subtraction and  the index registers
	(E)SI and (E)DI are incremented or decremented depending on the
	state of the Direction Flag.  CMPSB inc/decrements the index
	registers by 1, CMPSW inc/decrements by 2, while CMPSD increments
	or decrements by 4.  The REP prefixes can be used to process
	entire data items.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	dest,src	  22	8     10    8		  1  (W88=30)


	- see ~Instruction Timing~

:cmpxchg
^CMPXCHG - Compare and Exchange

	Usage:	CMPXCHG	dest,src  (486+)
	Modifies flags: AF CF OF PF SF ZF


	Compares the accumulator (8-32 bits) with "dest".  If equal the
	"dest" is loaded with "src", otherwise the accumulator is loaded
	with "dest".


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg		  -	-     -     6		  2
	mem,reg		  -     -     -     7		  2


	- add 3 clocks if the "mem,reg" comparison fails
	- see ~Instruction Timing~

:cwd
^CWD - Convert Word to Doubleword


	Usage:	CWD
	Modifies flags: None


	Extends sign of word in register AX throughout register DX forming
	a doubleword quantity in DX:AX.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  5	2     2	    3		  1


	- see ~Instruction Timing~

:cwde
^CWDE - Convert Word to Extended Doubleword  (386+ only)


	Usage:	CWDE
	Modifies flags: None


	Converts a signed word in AX to a signed doubleword in EAX by
	extending the sign bit of AX throughout EAX.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  -	-     3	    3		  1


	- see ~Instruction Timing~

:daa
^DAA - Decimal Adjust for Addition


	Usage:	DAA
	Modifies flags: AF CF PF SF ZF (OF undefined)


	Corrects result (in AL) of a previous BCD addition operation.
	Contents of AL are changed to a pair of packed decimal digits.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  4	3     4	    2		  1


	- see ~Instruction Timing~

:das
^DAS - Decimal Adjust for Subtraction


	Usage:	DAS
	Modifies flags: AF CF PF SF ZF (OF undefined)


	Corrects result (in AL) of a previous BCD subtraction operation.
	Contents of AL are changed to a pair of packed decimal digits.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  4	3     4	    2		  1


	- see ~Instruction Timing~

:dec
^DEC - Decrement


	Usage:	DEC	dest
	Modifies flags: AF OF PF SF ZF


	Unsigned binary subtraction of one from the destination.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  3	2     2	    1		  2
	mem		15+EA	7     6	    3		 2-4
	reg16/32	  3	2     2	    1		  1


	- see ~Instruction Timing~

:div
^DIV - Divide

	Usage:	DIV	src
	Modifies flags: (AF,CF,OF,PF,SF,ZF undefined)

	Unsigned binary division of accumulator by source.  If the source
	divisor is a byte value then AX is divided by "src" and the quotient
	is placed in AL and the remainder in AH.  If source operand is a word
	value, then DX:AX is divided by "src" and the quotient is stored in AX
	and the remainder in DX.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		 80-90	14    14    16		  2
	reg16		144-162 22    22    24		  2
	reg32		   -	-     38    40		  2
	mem8	    (86-96)+EA	17    17    16		 2-4
	mem16	  (150-168)+EA	25    25    24		 2-4  (W88=158-176+EA)
	mem32		   -	-     41    40		 2-4


	- see ~Instruction Timing~

:enter
^ENTER - Make Stack Frame  (80188+)


	Usage:	ENTER	locals,level
	Modifies flags: None


	Modifies stack for entry to procedure for high level language.
	Operand "locals" specifies the amount of storage to be allocated
	on the stack.	"Level" specifies the nesting level of the routine.
	Paired with the ~LEAVE~ instruction, this is an efficient method of
	entry and exit to procedures.


%				     Clocks			Size
%	Operands	 808x	 286	   386	     486	Bytes

	immed16,0	  -	  11	   10	      14  	  4
	immed16,1	  -	  15	   12	      17  	  4
	immed16,immed8	  -   12+4(n-1) 15+4(n-1)    17+3n	  4


	- see ~Instruction Timing~

:esc
^ESC - Escape


	Usage:	ESC	immed,src
	Modifies flags: None


	Provides access to the data bus for other resident processors.
	The CPU treats it as a ~NOP~ but places memory operand on bus.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	immed,reg	  2   9-20    ?			  2
	immed,mem	  2   9-20    ?			 2-4


	- see ~Instruction Timing~

:hlt
^HLT - Halt CPU


	Usage:	 HLT
	Modifies flags: None


	Halts CPU until RESET line is activated, NMI or maskable interrupt
	received.  The CPU becomes dormant but retains the current CS:IP
	for later restart.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     5	    4		  1


	- see ~Instruction Timing~

:idiv
^IDIV - Signed Integer Division

	Usage:	 IDIV	src
	Modifies flags: (AF,CF,OF,PF,SF,ZF undefined)

	Signed binary division of accumulator by source.  If source is a
	byte value, AX is divided by "src" and the quotient is stored in
	AL and the remainder in AH.  If source is a word value, DX:AX is
	divided by "src", and the quotient is stored in AL and the
	remainder in DX.
%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8	      101-112	17    19    19		  2
	reg16	      165-184	25    27    27		  2
	reg32		 -	-     43    43		  2
	mem8	 (107-118)+EA	20    22    20		 2-4
	mem16	 (171-190)+EA	38    30    28		 2-4  (W88=175-194)
	mem32		 -	-     46    44		 2-4


	- see ~Instruction Timing~

:imul
^IMUL - Signed Multiply

	Usage:	IMUL	src
		IMUL	src,immed  (286+ only)
		IMUL	dest,src,immed8  (286+ only)
		IMUL	dest,src  (386+ only)
	Modifies flags: CF OF (AF,PF,SF,ZF undefined)


	Signed multiplication of accumulator by "src" with result placed
	in the accumulator.  If the source operand is a byte value, it
	is multiplied by AL and the result stored in AX.  If the source
	operand is a word value it is multiplied by AX and the result is
	stored in DX:AX.  Other variations of this instruction allow
	specification of source and destination registers as well as a
	third immediate factor.

%				  Clocks		Size
%	Operands	 808x	286   386   486		Bytes

	reg8		 80-98	 13   9-14  13-18	  2
	reg16		128-154	 21   9-22  13-26	  2
	reg32		   -	 -    9-38  12-42	  2
	mem8		 86-104	 16  12-17  13-18	 2-4
	mem16		134-160	 24  12-25  13-26	 2-4
	mem32		   -	 -   12-41  13-42	 2-4
	reg16,reg16	   -	 -    9-22  13-26	 3-5
	reg32,reg32	   -	 -    9-38  13-42	 3-5
	reg16,mem16	   -	 -   12-25  13-26	 3-5
	reg32,mem32	   -	 -   12-41  13-42	 3-5
	reg16,immed	   -	 21   9-22  13-26	  3
	reg32,immed	   -	 21   9-38  13-42	 3-6
	reg16,reg16,immed  -	 2    9-22  13-26 	 3-6
	reg32,reg32,immed  -	 21   9-38  13-42	 3-6
	reg16,mem16,immed  -	 24  12-25  13-26	 3-6
	reg32,mem32,immed  -	 24  12-41  13-42	 3-6


	- see ~Instruction Timing~

:in
^IN - Input Byte or Word From Port


	Usage:	IN	accum,port
	Modifies flags: None


	A byte, word or dword is read from "port" and placed in AL, AX or
	EAX respectively.  If the port number is in the range of 0-255
	it can be specified as an immediate, otherwise the port number
	must be specified in DX.  Valid port ranges on the PC are 0-1024,
	though values through 65535 may be specified and recognized by
	third party vendors and PS/2's.


%				 Clocks			Size
%	Operands	 808x  286   386    486		Bytes

	accum,immed8	10/14	5     12     14		  2
	accum,immed8 (PM)	     6/26  8/28/27  	  2
	accum,DX	 8/12	5     13     14		  1
	accum,DX (PM)		     7/27  8/28/27  	  1


	- 386+ protected mode timings depend on privilege levels.

	  first number is the timing if:    CPL ó IOPL
	  second number is the timing if:   CPL > IOPL or in VM 86 mode (386)
	  			     	    CPL ò IOPL  (486)
	  third number is the timing when:    virtual mode on 486 processor
	- 486 virtual mode always requires 27 cycles

	- see ~Instruction Timing~

:inc
^INC - Increment


	Usage:	INC	dest
	Modifies flags: AF OF PF SF ZF


	Adds one to destination unsigned binary operand.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  3	2     2	    1		  2
	reg16		  3	2     2	    1		  1
	reg32		  3	2     2	    1		  1
	mem		15+EA	7     6	    3		 2-4  (W88=23+EA)


	- see ~Instruction Timing~

:ins:insb:insw:insd
^INS - Input String from Port  (80188+)


	Usage:	INS	dest,port
		INSB
		INSW
		INSD  (386+ only)
	Modifies flags: None

	Loads data from port to the destination ES:(E)DI  (even if a
	destination operand is supplied).  (E)DI is adjusted by the size
	of the operand and increased if the Direction Flag is cleared and
	decreased if the Direction Flag is set.  For INSB, INSW, INSD no
	operands are allowed and the size is determined by the mnemonic.


%				 Clocks			Size
%	Operands	 808x  286   386    486		Bytes

	dest,port	  -	5     15     17		  1
	dest,port (PM)	  -	5    9/29 10/32/30	  1
	none		  -	5     15     17		  1
	none (PM)	  -	5    9/29 10/32/30	  1


	- 386+ protected mode timings depend on privilege levels.

	  first number is the timing if:    CPL ó IOPL
	  second number is the timing if:   CPL > IOPL
	  third number is the timing if:    virtual mode on 486 processor

	- see ~Instruction Timing~

:int
^INT - Interrupt


	Usage:	INT	num
	Modifies flags: TF IF

	Initiates a software interrupt by pushing the flags, clearing the
	Trap and Interrupt Flags, pushing CS followed by IP and loading
	CS:IP with the value found in the interrupt vector table.  Execution
	then begins at the location addressed by the new CS:IP


%					       Clocks		Size
%	    Operands			808x  286   386   486	Bytes

 3 (constant)	       		       52/72  23+m   33    26	  2
 3 (prot. mode, same priv.)		 -    40+m   59	   44	  2	  
 3 (prot. mode, more priv.)		 -    78+m   99	   71	  2
 3 (from VM86 to PL 0)			 -     -    119	   82	  2
 3 (prot. mode via task gate)		 -   167+m   TS	 37+TS	  2
 immed8				       51/71  23+m   37    30 	  1
 immed8 (prot. mode, same priv.)	 -    40+m   59	   44	  1
 immed8 (prot. mode, more priv.)	 -    78+m   99	   71	  1
 immed8 (from VM86 to PL 0)		 -     -    119	   86	  1
 immed8 (prot. mode, via task gate)	 -   167+m   TS	 37+TS	  1


	- see ~Instruction Timing~

:into
^INTO - Interrupt on Overflow


	Usage:	INTO
	Modifies flags: IF TF


	If the Overflow Flag is set this instruction generates an INT 4
	which causes the code addressed by 0000:0010 to be executed.


%					  Clocks	   Size
%	Operands		808x	286   386   486	   Bytes

	none: jump	       53/73   24+m    35    28	     1
	      no jump		 4	 3     3     3
	(prot. mode, same priv.) -	 -     59    46	     1
	(prot. mode, more priv.) -	 -     99    73	     1
	(from VM86 to PL 0)	 -	 -    119    84	     1
	(prot. mode, via task gate)	 -     TS  39+TS     1


	- see ~Instruction Timing~

:invd
^INVD - Invalidate Cache  (486+ only)


	Usage:	INVD
	Modifies flags: none


	Flushes CPU internal cache.  Issues special function bus cycle
	which indicates to flush external caches.   Data in write-back
	external caches is lost.

	
%				  Clocks		Size
%	Operands	 808x	286   386   486		Bytes

	none		  -	 -     -     4		  2


	- see ~Instruction Timing~

:invlpg
^INVLPG - Invalidate Translation Look-Aside Buffer Entry  (486+ only)


	Usage:	INVLPG
	Modifies flags: none


	Invalidates a single page table entry in the Translation
	Look-Aside Buffer.  Intel warns that this instruction may be
	implemented differently on future processors.

	
%				  Clocks		Size
%	Operands	 808x	286   386   486		Bytes

	none		  -	 -     -     12		  2


	- timing is for TLB entry hit only.
	- see ~Instruction Timing~

:iret:iretd
^IRET/IRETD - Interrupt Return

	Usage:	IRET
		IRETD  (386+ only)
	Modifies flags: AF CF DF IF PF SF TF ZF

	Returns control to point of interruption by popping IP, CS
	and then the Flags from the stack and continues execution at
	this location.	CPU exception interrupts will return to the
	instruction that cause the exception because the CS:IP placed
	on the stack during the interrupt is the address of the offending
	instruction.

%					 Clocks			Size
%	    Operands		808x   286   386   486		Bytes

    iret		       32/44  17+m    22    15		  1
    iret  (prot. mode)	         -    31+m    38    15		  1
    iret  (to less privilege)	 -    55+m    82    36		  1
    iret  (different task, NT=1) -   169+m    TS  TS+32		  1
    iretd			 -	-   22/38   15		  1
    iretd (to less privilege)	 -	-     82    36		  1
    iretd (to VM86 mode)	 -	-     60    15		  1
    iretd (different task, NT=1) -	-     TS  TS+32		  1


    - 386 timings are listed as real-mode/protected-mode
	- see ~Instruction Timing~

:j...
^Jump Instructions Table

%	Mnemonic	      Meaning			 Jump Condition

	  ~JA~	   Jump if Above			 CF=0 and ZF=0
	  ~JAE~	   Jump if Above or Equal		 CF=0
	  ~JB~	   Jump if Below			 CF=1
	  ~JBE~	   Jump if Below or Equal		 CF=1 or ZF=1
	  ~JC~	   Jump if Carry			 CF=1
	  ~JCXZ~   Jump if CX Zero			 CX=0
	  ~JE~	   Jump if Equal			 ZF=1
	  ~JG~	   Jump if Greater (signed)		 ZF=0 and SF=OF
	  ~JGE~	   Jump if Greater or Equal (signed)	 SF=OF
	  ~JL~	   Jump if Less (signed)		 SF != OF
	  ~JLE~	   Jump if Less or Equal (signed)	 ZF=1 or SF != OF
	  ~JMP~	   Unconditional Jump			 unconditional
	  ~JNA~	   Jump if Not Above			 CF=1 or ZF=1
	  ~JNAE~   Jump if Not Above or Equal		 CF=1
	  ~JNB~	   Jump if Not Below			 CF=0
	  ~JNBE~   Jump if Not Below or Equal		 CF=0 and ZF=0
	  ~JNC~	   Jump if Not Carry			 CF=0
	  ~JNE~	   Jump if Not Equal			 ZF=0
	  ~JNG~	   Jump if Not Greater (signed) 	 ZF=1 or SF != OF
	  ~JNGE~   Jump if Not Greater or Equal (signed) SF != OF
	  ~JNL~	   Jump if Not Less (signed)		 SF=OF
	  ~JNLE~   Jump if Not Less or Equal (signed)	 ZF=0 and SF=OF
	  ~JNO~	   Jump if Not Overflow (signed)	 OF=0
	  ~JNP~	   Jump if No Parity			 PF=0
	  ~JNS~	   Jump if Not Signed (signed)		 SF=0
	  ~JNZ~	   Jump if Not Zero			 ZF=0
	  ~JO~	   Jump if Overflow (signed)		 OF=1
	  ~JP~	   Jump if Parity			 PF=1
	  ~JPE~	   Jump if Parity Even			 PF=1
	  ~JPO~	   Jump if Parity Odd			 PF=0
	  ~JS~	   Jump if Signed (signed)		 SF=1
	  ~JZ~	   Jump if Zero 			 ZF=1

%	      			 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	Jx: jump	  16   7+m   7+m    3		  2
	    no jump	   4	3     3	    1
	Jx  near-label	   -	-    7+m    3		  4
	    no jump	   -	-     3	    1


	- It's a good programming practice to organize code so the
	  expected case is executed without a jump since the actual
	  jump takes longer to execute than falling through the test.
	- see	~JCXZ~  and  ~JMP~  for their respective timings
	- see   ~Instruction Timing~   ~FLAGS~

:ja:jnbe
^JA/JNBE - Jump Above / Jump Not Below or Equal


	Usage:	JA	label
		JNBE	label
	Modifies flags: None


	Causes execution to branch to "label" if the Carry Flag and Zero Flag
	are both clear.  Unsigned comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jae:jnb
^JAE/JNB - Jump Above or Equal / Jump on Not Below


	Usage:	JAE	label
		JNB	label
	Modifies flags: None


	Causes execution to branch to "label" if the Carry Flag is clear.
	Functionally similar to ~JNC~.  Unsigned comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jb:jnae
^JB/JNAE - Jump Below / Jump Not Above or Equal


	Usage:	JB	label
		JNAE	label
	Modifies flags: None


	Causes execution to branch to "label" if the Carry Flag is set.
	Functionally similar to ~JC~.  Unsigned comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jbe:jna
^JBE/JNA - Jump Below or Equal / Jump Not Above


	Usage:	JBE	label
		JNA	label
	Modifies flags: None


	Causes execution to branch to "label" if the Carry Flag or
	the Zero Flag is set.	Unsigned comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jc
^JC - Jump on Carry


	Usage:	JC	label
	Modifies flags: None


	Causes execution to branch to "label" if the Carry Flag is set.
	Functionally similar to ~JB~ and ~JNAE~.  Unsigned comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jcxz:jecxz
^JCXZ/JECXZ - Jump if Register (E)CX is Zero


	Usage:	JCXZ	label
		JECXZ	label  (386+ only)
	Modifies flags: None


	Causes execution to branch to "label" if register CX is zero.  Uses
	unsigned comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  18   8+m   9+m    8		  2
		no jump	   6	4     5	    5


	- see ~Instruction Timing~

:je:jz
^JE/JZ - Jump Equal / Jump Zero


	Usage:	JE	label
		JZ	label
	Modifies flags: None


	Causes execution to branch to "label" if the Zero Flag is set.	Uses
	unsigned comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jg:jnle
^JG/JNLE - Jump Greater / Jump Not Less or Equal


	Usage:	JG	label
		JNLE	label
	Modifies flags: None


	Causes execution to branch to "label" if the Zero Flag is clear or
	the Sign Flag equals the Overflow Flag.  Signed comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jge:jnl
^JGE/JNL - Jump Greater or Equal / Jump Not Less


	Usage:	JGE	label
		JNL	label
	Modifies flags: None


	Causes execution to branch to "label" if the Sign Flag equals
	the Overflow Flag.  Signed comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jl:jnge
^JL/JNGE - Jump Less / Jump Not Greater or Equal


	Usage:	JL	label
		JNGE	label
	Modifies flags: None


	Causes execution to branch to "label" if the Sign Flag is not equal
	to Overflow Flag.  Unsigned comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jle:jng
^JLE/JNG - Jump Less or Equal / Jump Not Greater


	Usage:	JLE	label
		JNG	label
	Modifies flags: None


	Causes execution to branch to "label" if the Zero Flag is set or the
	Sign Flag is not equal to the Overflow Flag.  Signed comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jmp
^JMP - Unconditional Jump

	Usage:	JMP	target
	Modifies flags: None

	Unconditionally transfers control to "label".  Jumps by default
	are within -32768 to 32767 bytes from the instruction following
	the jump.  NEAR and SHORT jumps cause the IP to be updated while FAR
	jumps cause CS and IP to be updated.

%							Clocks
%		   Operands			808x  286    386   486

	rel8  (relative)		 	15    7+m    7+m    3
	rel16 (relative)		 	15    7+m    7+m    3
	rel32 (relative)		 	 -     -     7+m    3
	reg16 (near, register indirect)		11    7+m    7+m    5
	reg32 (near, register indirect)		 -     -     7+m    5
	mem16 (near, mem indirect)	       18+EA  11+m  10+m    5
	mem32 (near, mem indirect)	       24+EA  15+m  10+m    5
	ptr16:16 (far, dword immed)		 -     -    12+m    17
	ptr16:16 (far, PM dword immed)		 -     -    27+m    19
	ptr16:16 (call gate, same priv.)	 -    38+m  45+m    32
	ptr16:16 (via TSS)		       	 -   175+m   TS	  42+TS
	ptr16:16 (via task gate)		 -   180+m   TS	  43+TS
	mem16:16 (far, indirect)		 -     -    43+m    13
	mem16:16 (far, PM indirect)		 -     -    31+m    18
	mem16:16 (call gate, same priv.)	 -    41+m  49+m    31
	mem16:16 (via TSS)		   	 -   178+m  5+TS  41+TS
	mem16:16 (via task gate)	   	 -   183+m  5+TS  42+TS
	ptr16:32 (far, 6 byte immed)		 -     -    12+m    13
	ptr16:32 (far, PM 6 byte immed)		 -     -    27+m    18
	ptr16:32 (call gate, same priv.)	 -     -    45+m    31
	ptr16:32 (via TSS)			 -     -     TS	  42+TS
	ptr16:32 (via task state) 		 -     -     TS	  43+TS
	m16:32 (far, address at dword)		 -     -    43+m    13
	m16:32 (far, address at dword)		 -     -    31+m    18
	m16:32 (call gate, same priv.)		 -     -    49+m    31
	m16:32 (via TSS)			 -     -    5+TS  41+TS
	m16:32 (via task state)			 -     -    5+TS  42+TS

 - see ~Instruction Timing~

:jnc
^JNC - Jump Not Carry


	Usage:	JNC	label
	Modifies flags: None


	Causes execution to branch to "label" if the Carry Flag is clear.
	Functionally similar to ~JAE~ or ~JNB~.  Unsigned comparision.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jne:jnz
^JNE/JNZ - Jump Not Equal / Jump Not Zero


	Usage:	JNE	label
		JNZ	label
	Modifies flags: None


	Causes execution to branch to "label" if the Zero Flag is clear.
	Unsigned comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jno
^JNO - Jump Not Overflow


	Usage:	JNO	label
	Modifies flags: None


	Causes execution to branch to "label" if the Overflow Flag is clear.
	Signed comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jns
^JNS - Jump Not Signed


	Usage:	JNS	label
	Modifies flags: None


	Causes execution to branch to "label" if the Sign Flag is clear.
	Signed comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jnp:jpo
^JNP/JPO - Jump Not Parity / Jump Parity Odd


	Usage:	JNP	label
		JPO	label
	Modifies flags: None


	Causes execution to branch to "label" if the Parity Flag is clear.
	Unsigned comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jo
^JO - Jump on Overflow


	Usage:	JO  label
	Modifies flags: None


	Causes execution to branch to "label" if the Overflow Flag is set.
	Signed comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:jp:jpe
^JP/JPE - Jump on Parity / Jump on Parity Even


	Usage:	JP	label
		JPE	label
	Modifies flags: None


	Causes execution to branch to "label" if the Parity Flag is set.
	Unsigned comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:js
^JS - Jump Signed


	Usage:	JS	label
	Modifies flags: None


	Causes execution to branch to "label" if the Sign Flag is set.
	Signed comparision.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  16   7+m   7+m    3		 2-4
		no jump	  4	3     3	    1


	- see ~Instruction Timing~

:lahf
^LAHF - Load Register AH From Flags


	Usage:	LAHF
	Modifies flags: None

	Copies bits 0-7 of the flags register into AH.	This includes flags
	AF, CF, PF, SF and ZF other bits are undefined.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  4	2     2	    3		  1


	- see ~Instruction Timing~

:lar
^LAR - Load Access Rights  (286+ protected)


	Usage:	LAR	dest,src
	Modifies flags: ZF


	The high byte of the of the destination register is overwritten by
	the value of the access rights byte and the low order byte is zeroed
	depending on the selection in the source operand.  The Zero Flag is
	set if the load operation is successful.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,reg16	  -	14    15    11		  3
	reg32,reg32	  -	-     15    11		  3
	reg16,mem16	  -	16    16    11		 3-7
	reg32,mem32	  -	-     16    11		 3-7


	- see ~Instruction Timing~

:lds
^LDS - Load Pointer Using DS

	Usage:	LDS	dest,src
	Modifies flags: None


	Loads 32-bit pointer from memory source to destination register
	and DS.  The offset is placed in the destination register and the
	segment is placed in DS.  To use this instruction the word at the
	lower memory address must contain the offset and the word at the
	higher address must contain the segment.  This simplifies the loading
	of far pointers from the stack and the interrupt vector table.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,mem32	16+EA	7     7	    6		 2-4
	reg,mem (PM)	  -	-     22    12		 5-7


	- see ~Instruction Timing~

:lea
^LEA - Load Effective Address


	Usage:	LEA	dest,src
	Modifies flags: None


	Transfers offset address of "src" to the destination register.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,mem 	 2+EA	3     2	    1		 2-4


	- see ~Instruction Timing~

:leave
^LEAVE - Restore Stack for Procedure Exit (80188+)


	Usage:	LEAVE
	Modifies flags: None


	Releases the local variables created by the previous ~ENTER~
	instruction by restoring SP and BP to their condition before
	the procedure stack frame was initialized.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  -	5     4	    5		  1


	- see ~Instruction Timing~

:les
^LES - Load Pointer Using ES

	Usage:	LES	dest,src
	Modifies flags: None


	Loads 32-bit pointer from memory source to destination register
	and ES.  The offset is placed in the destination register and the
	segment is placed in ES.  To use this instruction the word at the
	lower memory address must contain the offset and the word at the
	higher address must contain the segment.  This simplifies the loading
	of far pointers from the stack and the interrupt vector table.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,mem 	16+EA	7     7	    6		 2-4  (W88=24+EA)
	reg,mem (PM)	  -	-     22    12		 5-7


	- see ~Instruction Timing~

:lfs
^LFS - Load Pointer Using FS  (386+ only)


	Usage:	LFS	dest,src
	Modifies flags: None


	Loads 32-bit pointer from memory source to destination register
	and FS.  The offset is placed in the destination register and the
	segment is placed in FS.  To use this instruction the word at the
	lower memory address must contain the offset and the word at the
	higher address must contain the segment.  This simplifies the loading
	of far pointers from the stack and the interrupt vector table.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,mem 	  -	-     7	    6		 5-7
	reg,mem (PM)	  -	-     22    12		 5-7


	- see ~Instruction Timing~

:lgdt
^LGDT - Load Global Descriptor Table  (286+ privileged)


	Usage:	LGDT	src
	Modifies flags: None


	Loads a value from an operand into the Global Descriptor Table
	(~GDT~) register.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	mem64		  -	11    11    11		  5


	- see ~Instruction Timing~

:lidt
^LIDT - Load Interrupt Descriptor Table  (286+ privileged)


	Usage:	LIDT	src
	Modifies flags: None


	Loads a value from an operand into the Interrupt Descriptor Table
	(IDT) register.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	mem64		  -	12    11    11		  5


	- see ~Instruction Timing~

:lgs
^LGS - Load Pointer Using GS  (386+ only)


	Usage:	LGS	dest,src
	Modifies flags: None


	Loads 32-bit pointer from memory source to destination register
	and GS.  The offset is placed in the destination register and the
	segment is placed in GS.  To use this instruction the word at the
	lower memory address must contain the offset and the word at the
	higher address must contain the segment.  This simplifies the loading
	of far pointers from the stack and the interrupt vector table.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,mem 	  -	-     7	    6		 5-7
	reg,mem (PM)	  -	-     22    12		 5-7


	- see ~Instruction Timing~

:lldt
^LLDT - Load Local Descriptor Table  (286+ privileged)


	Usage:	LLDT	src
	Modifies flags: None


	Loads a value from an operand into the Local Descriptor Table 
	Register (LDTR).


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	17    20    11		  3
	mem16		  -	19    24    11		  5


	- see ~Instruction Timing~

:lmsw
^LMSW - Load Machine Status Word  (286+ privileged)


	Usage:	LMSW	src
	Modifies flags: None


	Loads the Machine Status Word (~MSW~) from data found at "src"


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	3     10    13		  3
	mem16		  -	6     13    13		  5


	- see ~Instruction Timing~

:lock
^LOCK - Lock Bus


	Usage:	LOCK
		LOCK: (386+ prefix)
	Modifies flags: None


	This instruction is a prefix that causes the CPU assert bus lock
	signal during the execution of the next instruction.  Used to
	avoid two processors from updating the same data location.  The
	286 always asserts lock during an XCHG with memory operands.  This
	should only be used to lock the bus prior to ~XCHG~, ~MOV~, ~IN~ and
	~OUT~ instructions.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	0     0	    1		  1


	- see ~Instruction Timing~

:lods:lodsb:lodsw:lodsd
^LODS - Load String (Byte, Word or Double)


	Usage:	LODS	src
		LODSB
		LODSW
		LODSD  (386+ only)
	Modifies flags: None

	Transfers string element addressed by DS:SI (even if an operand is
	supplied) to the accumulator.	SI is incremented based on the size
	of the operand or based on the instruction used.  If the Direction
	Flag is set SI is decremented, if the Direction Flag is clear SI
	is incremented.  Use with REP prefixes.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	src		12/16	5     5	    5		  1


	- see ~Instruction Timing~

:loop
^LOOP - Decrement CX and Loop if CX Not Zero


	Usage:	LOOP	label
	Modifies flags: None


	Decrements CX by 1 and transfers control to "label" if CX is not
	Zero.  The "label" operand must be within -128 or 127 bytes of the
	instruction following the loop instruction


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  18   8+m  11+m    6		  2
		no jump	   5	4     ?	    2


	- see ~Instruction Timing~

:loope:loopz
^LOOPE/LOOPZ - Loop While Equal / Loop While Zero


	Usage:	LOOPE	label
		LOOPZ	label
	Modifies flags: None

	Decrements CX by 1 (without modifying the flags) and transfers
	control to "label" if CX != 0 and the Zero Flag is set.  The
	"label" operand must be within -128 or 127 bytes of the instruction
	following the loop instruction.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  18   8+m  11+m    9		  2
		no jump	   5	4     ?	    6


	- see ~Instruction Timing~

:loopnz:loopne
^LOOPNZ/LOOPNE - Loop While Not Zero / Loop While Not Equal


	Usage:	LOOPNZ	label
		LOOPNE	label
	Modifies flags: None

	Decrements CX by 1 (without modifying the flags) and transfers
	control to "label" if CX != 0 and the Zero Flag is clear.  The
	"label" operand must be within -128 or 127 bytes of the instruction
	following the loop instruction.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	label:	jump	  19   8+m  11+m    9		  2
		no jump	   5	4     ?	    6


	- see ~Instruction Timing~

:lsl
^LSL - Load Segment Limit  (286+ protected)


	Usage:	LSL	dest,src
	Modifies flags: ZF

	Loads the segment limit of a selector into the destination register
	if the selector is valid and visible at the current privilege level.
	If loading is successful the Zero Flag is set, otherwise it is
	cleared.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16,reg16	  -	14  20/25   10		  3
	reg32,reg32	  -	-   20/25   10		  3
	reg16,mem16	  -	16  21/26   10		  5
	reg32,mem32	  -	-   21/26   10		  5


	- 386 times are listed "byte granular" / "page granular"
	- see ~Instruction Timing~
:lss
^LSS - Load Pointer Using SS  (386+ only)


	Usage:	LSS	dest,src
	Modifies flags: None


	Loads 32-bit pointer from memory source to destination register
	and SS.  The offset is placed in the destination register and the
	segment is placed in SS.  To use this instruction the word at the
	lower memory address must contain the offset and the word at the
	higher address must contain the segment.  This simplifies the loading
	of far pointers from the stack and the interrupt vector table.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,mem 	  -	-     7	    6		 5-7
	reg,mem (PM)	  -	-     22    12		 5-7


	- see ~Instruction Timing~

:ltr
^LTR - Load Task Register   (286+ privileged)


	Usage:	LTR	src
	Modifies flags: None


	Loads the current task register with the value specified in "src".


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	17    23    20		  3
	mem16		  -	19    27    20		  5


	- see ~Instruction Timing~

:mov
^MOV - Move Byte or Word

	Usage:	MOV	dest,src
	Modifies flags: None

	Copies byte or word from the source operand to the destination
	operand.  If the destination is SS interrupts are disabled except
	on early buggy 808x CPUs.  Some CPUs disable interrupts if the
	destination is any of the segment registers

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  2	2     2	    1		  2
	mem,reg 	 9+EA	3     2	    1		 2-4  (W88=13+EA)
	reg,mem 	 8+EA	5     4	    1		 2-4  (W88=12+EA)
	mem,immed	10+EA	3     2	    1		 3-6  (W88=14+EA)
	reg,immed	  4	2     2	    1		 2-3
	mem,accum	  10	3     2	    1		  3   (W88=14)
	accum,mem	  10	5     4	    1		  3   (W88=14)
	segreg,reg16	  2	2     2	    3		  2
	segreg,mem16	 8+EA	5     5	    9		 2-4  (W88=12+EA)
	reg16,segreg	  2	2     2	    3		  2
	mem16,segreg	 9+EA	3     2	    3		 2-4  (W88=13+EA)
	reg32,CR0/CR2/CR3 -	-     6	    4
	CR0,reg32	  -	-     10    16
	CR2,reg32	  -	-     4     4 		  3
	CR3,reg32	  -	-     5     4 		  3
	reg32,DR0/DR1/DR2/DR3	-     22   10		  3
	reg32,DR6/DR7	  -     -     22   10		  3
	DR0/DR1/DR2/DR3,reg32   -     22   11		  3
	DR6/DR7,reg32	  -	-     16   11		  3
	reg32,TR6/TR7 	  -	-     12    4		  3
	TR6/TR7,reg32 	  -	-     12    4		  3
	reg32,TR3			    3
	TR3,reg32			    6

	- when the 386 special registers are used all operands are 32 bits
	- see ~Instruction Timing~

:movs:movsb:movsw:movsd
^MOVS - Move String (Byte or Word)

	Usage:	MOVS	dest,src
		MOVSB
		MOVSW
		MOVSD  (386+ only)
	Modifies flags: None


	Copies data from addressed by DS:SI (even if operands are given) to
	the location ES:DI destination and updates SI and DI based on the
	size of the operand or instruction used.  SI and DI are incremented
	when the Direction Flag is cleared and decremented when the Direction
	Flag is Set.  Use with ~REP~ prefixes.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	dest,src	  18	5     7	    7		  1   (W88=26)


	- see ~Instruction Timing~

:movsx
^MOVSX - Move with Sign Extend	(386+ only)


	Usage:	MOVSX	dest,src
	Modifies flags: None


	Copies the value of the source operand to the destination register
	with the sign extended.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  -	-     3	    3		  3
	reg,mem 	  -	-     6	    3		 3-7


	- see ~Instruction Timing~

:movzx
^MOVZX - Move with Zero Extend	(386+ only)


	Usage:	MOVZX	dest,src
	Modifies flags: None


	Copies the value of the source operand to the destination register
	with the zeroes extended.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  -	-     3	    3		  3
	reg,mem 	  -	-     6	    3		 3-7


	- see ~Instruction Timing~

:mul
^MUL - Unsigned Multiply

	Usage:	MUL	src
	Modifies flags: CF OF (AF,PF,SF,ZF undefined)

	Unsigned multiply of the accumulator by the source.  If "src" is
	a byte value, then AL is used as the other multiplicand and the
	result is placed in AX.  If "src" is a word value, then AX is
	multiplied by "src" and DX:AX receives the result.  If "src" is
	a double word value, then EAX is multiplied by "src" and EDX:EAX
	receives the result.  The 386+ uses an early out algorithm which
	makes multiplying any size value in EAX as fast as in the 8 or 16
	bit registers.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		70-77	13   9-14  13-18	  2
	reg16	       118-113	21   9-22  13-26	  2
	reg32		  -	-    9-38  13-42	 2-4
	mem8	    (76-83)+EA	16  12-17  13-18	 2-4
	mem16	  (124-139)+EA	24  12-25  13-26	 2-4
	mem32		  -	-   12-21  13-42	 2-4


	- see ~Instruction Timing~   ~IMUL~

:neg
^NEG - Two's Complement Negation


	Usage:	NEG	dest
	Modifies flags: AF CF OF PF SF ZF


	Subtracts the destination from 0 and saves the 2s complement of
	"dest" back into "dest".


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg		  3	2     2	    1		  2
	mem		16+EA	7     6	    3		 2-4  (W88=24+EA)


	- see ~Instruction Timing~

:nop
^NOP - No Operation (90h)


	Usage:	NOP
	Modifies flags: None


	This is a do nothing instruction.  It results in occupation of both
	space and time and is most useful for patching code segments.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  3	3     3	    1		  1


	- see ~Instruction Timing~

:not
^NOT - One's Compliment Negation (Logical NOT)


	Usage:	NOT	dest
	Modifies flags: None

	Inverts the bits of the "dest" operand forming the 1s complement.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg		  3	2     2	    1		  2
	mem		16+EA	7     6	    3		 2-4  (W88=24+EA)


	- see ~Instruction Timing~

:or
^OR - Inclusive Logical OR

	Usage:	OR	dest,src
	Modifies flags: CF OF PF SF ZF (AF undefined)

	Logical inclusive OR of the two operands returning the result in
	the destination.  Any bit set in either operand will be set in the
	destination.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	16+EA	7     7	    3		 2-4  (W88=24+EA)
	reg,mem 	 9+EA	7     6	    2		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem8,immed8	17+EA	7     7	    3		 3-6
	mem16,immed16	25+EA	7     7	    3		 3-6
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:out
^OUT - Output Data to Port


	Usage:	OUT	port,accum
	Modifies flags: None

	Transfers byte in AL,word in AX or dword in EAX to the specified
	hardware port address.  If the port number is in the range of 0-255
	it can be specified as an immediate.  If greater than 255 then the
	port number must be specified in DX.  Since the PC only decodes 10
	bits of the port address, values over 1023 can only be decoded by
	third party vendor equipment and also map to the port range 0-1023.


%				 Clocks			Size
%	Operands	 808x  286   386    486		Bytes

	immed8,accum	10/14	3     10     16		  2
	immed8,accum (PM) -    	-    4/24 11/31/29	  2
	DX,accum	 8/12	3     11     16		  1
	DX,accum (PM)	  -    	-    5/25 10/30/29	  1


	- 386+ protected mode timings depend on privilege levels.

	  first number is the timing when:    CPL ó IOPL
	  second number is the timing when:   CPL > IOPL
	  third number is the timing when:    virtual mode on 486 processor

	- see ~Instruction Timing~

:outs:outsb:outsw:outsd
^OUTS - Output String to Port  (80188+ only)


	Usage:	OUTS	port,src
		OUTSB
		OUTSW
		OUTSD  (386+ only)
	Modifies flags: None


	Transfers a byte, word or doubleword from "src" to the hardware
	port specified in DX.  For instructions with no operands the "src"
	is located at DS:SI and SI is incremented or decremented by the
	size of the operand or the size dictated by the instruction format.
	When the Direction Flag is set SI is decremented, when clear, SI is
	incremented.  If the port number is in the range of 0-255 it can
	be specified as an immediate.  If greater than 255 then the port
	number must be specified in DX.  Since the PC only decodes 10 bits
	of the port address, values over 1023 can only be decoded by third
	party vendor equipment and also map to the port range 0-1023.


%				 Clocks			Size
%	Operands	 808x  286   386    486		Bytes

	port,src	  -	5     14     17		  1
	port,src (PM)	  -	-    8/28 10/32/30	  1


	- 386+ protected mode timings depend on privilege levels.

	  first number is the timing when:    CPL ó IOPL
	  second number is the timing when:   CPL > IOPL
	  third number is the timing when:    virtual mode on 486 processor

	- see ~Instruction Timing~

:pop
^POP - Pop Word off Stack


	Usage:	POP	dest
	Modifies flags: None


	Transfers word at the current stack top (SS:SP) to the destination
	then increments SP by two to point to the new stack top.  CS is not
	a valid destination.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  8	5     4     4		  1
	reg32		  4	-     -	    4		  1
	segreg		  8	5     7	    3		  1
	mem16		17+EA	5     5     6		 2-4
	mem32		  5	-     -	    6		 2-4


	- see ~Instruction Timing~

:popa:popad
^POPA/POPAD - Pop All Registers onto Stack  (80188+ only)


	Usage:	POPA
		POPAD  (386+ only)
	Modifies flags: None


	Pops the top 8 words off the stack into the 8 general purpose 16/32
	bit registers.	 Registers are popped in the following order: (E)DI,
	(E)SI, (E)BP, (E)SP, (E)DX, (E)CX and (E)AX.  The (E)SP value popped
	from the stack is actually discarded.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  -	19    24    9		  1


	- see ~Instruction Timing~

:popf:popfd
^POPF/POPFD - Pop Flags off Stack


	Usage:	POPF
		POPFD  (386+ only)
	Modifies flags: all flags


	Pops word/doubleword from stack into the Flags Register and then
	increments SP by 2 (for POPF) or 4 (for POPFD).


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		 8/12	5     5	    9		  1  (W88=12)
	none  (PM)	  -	-     5     6		  1


	- see ~Instruction Timing~

:push
^PUSH - Push Word onto Stack

	Usage:	PUSH	src
		PUSH	immed	(80188+ only)
	Modifies flags: None


	Decrements SP by the size of the operand (two or four, byte values
	are sign extended) and transfers one word from source to the stack
	top (SS:SP).

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16	 	11/15	3     2     1		  1
	reg32	 	  -	-     2     1		  1
	mem16		16+EA	5     5     4	 	 2-4  (W88=24+EA)
	mem32	   	  -	-     5     4		 2-4
	segreg		10/14	3     2     3		  1
	immed		  -	3     2     1		 2-3


	- see ~Instruction Timing~

:pusha:pushad
^PUSHA/PUSHAD - Push All Registers onto Stack  (80188+ only)


	Usage:	PUSHA
		PUSHAD	(386+ only)
	Modifies flags: None


	Pushes all general purpose registers onto the stack in the following
	order: (E)AX, (E)CX, (E)DX, (E)BX, (E)SP, (E)BP, (E)SI, (E)DI.	The
	value of SP is the value before the actual push of SP.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  -	19    24    11		  1


	- see ~Instruction Timing~

:pushf:pushfd
^PUSHF/PUSHFD - Push Flags onto Stack


	Usage:	PUSHF
		PUSHFD	(386+ only)
	Modifies flags: None


	Transfers the Flags Register onto the stack.  PUSHF saves a 16 bit
	value while PUSHFD saves a 32 bit value.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		10/14	3     4	    4		  1
	none  (PM)	  -	-     4	    3		  1


	- see ~Instruction Timing~

:rcl
^RCL - Rotate Through Carry Left

	Usage:	RCL	dest,count
	Modifies flags: CF OF


	Rotates the bits in the destination to the left "count" times with
	all data pushed out the left side re-entering on the right.  The
	Carry Flag holds the last bit rotated out.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,1		  2	2     9	    3		 2
	mem,1		15+EA	7     10    4		2-4  (W88=23+EA)
	reg,CL		 8+4n  5+n    9	   8-30		 2
	mem,CL	      20+EA+4n 8+n    10   9-31		2-4  (W88=28+EA+4n)
	reg,immed8	  -    5+n     9   8-30		 3
	mem,immed8	  -    8+n    10   9-31		3-5


	- see ~Instruction Timing~

:rcr
^RCR - Rotate Through Carry Right

	Usage:	RCR	dest,count
	Modifies flags: CF OF


	Rotates the bits in the destination to the right "count" times with
	all data pushed out the right side re-entering on the left.  The
	Carry Flag holds the last bit rotated out.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,1		  2	2     9	    3		 2
	mem,1		15+EA	7     10    4		2-4   (W88=23+EA)
	reg,CL		 8+4n  5+n    9	   8-30		 2
	mem,CL	      20+EA+4n 8+n    10   9-31		2-4   (W88=28+EA+4n)
	reg,immed8	  -    5+n    9	   8-30		 3
	mem,immed8	  -    8+n    10   9-31		3-5


	- see ~Instruction Timing~

:rep
^REP - Repeat String Operation

	Usage:	REP
	Modifies flags: None

	Repeats execution of string instructions while CX != 0.  After
	each string operation, CX is decremented and the Zero Flag is
	tested.  The combination of a repeat prefix and a segment override
	on CPU's before the 386 may result in errors if an interrupt occurs
	before CX=0.  The following code shows code that is susceptible to
	this and how to avoid it:

	 again:  rep movs  byte ptr ES:[DI],ES:[SI]   ; vulnerable instr.
		     jcxz  next 	     ; continue if REP successful
		     loop  again	     ; interrupt goofed count
	 next:

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2			  1


	- see ~Instruction Timing~   ~REPE~   ~REPNE~
:repe:repz
^REPE/REPZ - Repeat Equal / Repeat Zero


	Usage:	REPE
		REPZ
	Modifies flags: None


	Repeats execution of string instructions while CX != 0 and the Zero
	Flag is set.  CX is decremented and the Zero Flag tested after
	each string operation.	 The combination of a repeat prefix and a
	segment override on processors other than the 386 may result in
	errors if an interrupt occurs before CX=0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2			  1


	- see ~Instruction Timing~

:repne:repnz
^REPNE/REPNZ - Repeat Not Equal / Repeat Not Zero


	Usage:	REPNE
		REPNZ
	Modifies flags: None


	Repeats execution of string instructions while CX != 0 and the Zero
	Flag is clear.	 CX is decremented and the Zero Flag tested after
	each string operation.	 The combination of a repeat prefix and a
	segment override on processors other than the 386 may result in
	errors if an interrupt occurs before CX=0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2			  1


	- see ~Instruction Timing~

:ret:retf:retn
^RET/RETF - Return From Procedure

	Usage:	RET	nBytes
		RETF	nBytes
		RETN	nBytes
	Modifies flags: None

	Transfers control from a procedure back to the instruction address
	saved on the stack.  "n bytes" is an optional number of bytes to
	release.  Far returns pop the IP followed by the CS, while near
	returns pop only the IP register.

%				 Clocks			Size
%	Operands	 808x  286    386   486		Bytes

	retn		16/20  11+m  10+m    5		  1
	retn immed	20/24  11+m  10+m    5		  3
	retf		26/34  15+m  18+m    13		  1
	retf (PM, same priv.)	-    32+m    18		  1
	retf (PM, lesser priv.)	-      68    33		  1
      	retf immed	25/33  15+m  18+m    14		  3
	retf immed (PM, same priv.)  32+m    17		  1
	retf immed (PM, lesser priv.)  68    33		  1


	- see ~Instruction Timing~

:rol
^ROL - Rotate Left

	Usage:	ROL	dest,count
	Modifies flags: CF OF


	Rotates the bits in the destination to the left "count" times with
	all data pushed out the left side re-entering on the right.  The
	Carry Flag will contain the value of the last bit rotated out.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,1		  2	2     3	    3		  2
	mem,1		15+EA	7     7	    4		 2-4  (W88=23+EA)
	reg,CL		 8+4n  5+n    3	    3		  2
	mem,CL	      20+EA+4n 8+n    7	    4		 2-4  (W88=28+EA+4n)
	reg,immed8	  -    5+n    3	    2		  3
	mem,immed8	  -    8+n    7	    4		 3-5


	- see ~Instruction Timing~

:ror
^ROR - Rotate Right

	Usage:	ROR	dest,count
	Modifies flags: CF OF


	Rotates the bits in the destination to the right "count" times with
	all data pushed out the right side re-entering on the left.  The
	Carry Flag will contain the value of the last bit rotated out.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,1		  2	2     3	    3		  2
	mem,1		15+EA	7     7	    4		 2-4  (W88=23+EA)
	reg,CL		 8+4n  5+n    3	    3		  2
	mem,CL	      20+EA+4n 8+n    7	    4		 2-4  (W88=28+EA+4n)
	reg,immed8	  -    5+n    3	    2		  3
	mem,immed8	  -    8+n    7	    4		 3-5


	- see ~Instruction Timing~

:sahf
^SAHF - Store AH Register into FLAGS


	Usage:	SAHF
	Modifies flags: AF CF PF SF ZF


	Transfers bits 0-7 of AH into the Flags Register.  This includes
	AF, CF, PF, SF and ZF.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  4	2     3	    2		  1


	- see ~Instruction Timing~

:sal:shl
^SAL/SHL - Shift Arithmetic Left / Shift Logical Left

	Usage:	SAL	dest,count
		SHL	dest,count
	Modifies flags: CF OF PF SF ZF (AF undefined)


	Shifts the destination left by "count" bits with zeroes shifted
	in on right.  The Carry Flag contains the last bit shifted out.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,1		  2	2     3	    3		 2
	mem,1		15+EA	7     7	    4		2-4  (W88=23+EA)
	reg,CL		 8+4n  5+n    3	    3		 2
	mem,CL	      20+EA+4n 8+n    7	    4		2-4  (W88=28+EA+4n)
	reg,immed8	  -    5+n    3	    2		 3
	mem,immed8	  -    8+n    7	    4		3-5


	- see ~Instruction Timing~

:sar
^SAR - Shift Arithmetic Right

	Usage:	SAR	dest,count
	Modifies flags: CF OF PF SF ZF (AF undefined)


	Shifts the destination right by "count" bits with the current sign
	bit replicated in the leftmost bit.  The Carry Flag contains the
	last bit shifted out.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,1		  2	2     3	    3		  2
	mem,1		15+EA	7     7	    4		 2-4  (W88=23+EA)
	reg,CL		 8+4n  5+n    3	    3		  2
	mem,CL	      20+EA+4n 8+n    7	    4		 2-4  (W88=28+EA+4n)
	reg,immed8	  -    5+n    3	    2		  3
	mem,immed8	  -    8+n    7	    4		 3-5


	- see ~Instruction Timing~

:sbb
^SBB - Subtract with Borrow

	Usage:	SBB	dest,src
	Modifies flags: AF CF OF PF SF ZF


	Subtracts the source from the destination, and subtracts 1 extra if
	the Carry Flag is set.	 Results are returned in "dest".


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	16+EA	7     6	    3		 2-4  (W88=24+EA)
	reg,mem 	 9+EA	7     7	    2		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem,immed	17+EA	7     7	    3		 3-6  (W88=25+EA)
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:scas:scasb:scasw:scasd
^SCAS - Scan String  (Byte, Word or Doubleword)


	Usage:	SCAS	string
		SCASB
		SCASW
		SCASD	(386+ only)
	Modifies flags: AF CF OF PF SF ZF


	Compares value at ES:DI (even if operand is specified) from the
	accumulator and sets the flags similar to a subtraction.  DI is
	incremented/decremented based on the instruction format (or
	operand size) and the state of the Direction Flag.  Use with REP
	prefixes.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	string		  15	7     7	    6		  1  (W88=19)


	- see ~Instruction Timing~

:setae:setnb
^SETAE/SETNB - Set if Above or Equal / Set if Not Below
^(unsigned, 386+ only)


	Usage:	SETAE	dest
		SETNB	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Carry Flag is clear
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setb:setnae
^SETB/SETNAE - Set if Below / Set if Not Above or Equal
^(unsigned, 386+ only)


	Usage:	SETB	dest
		SETNAE	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Carry Flag is set
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setbe:setna
^SETBE/SETNA - Set if Below or Equal / Set if Not Above
^(unsigned, 386+ only)


	Usage:	SETBE	dest
		SETNA	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Carry Flag or the Zero
	Flag is set, otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:sete:setz
^SETE/SETZ - Set if Equal / Set if Zero (386+ only)


	Usage:	SETE	dest
		SETZ	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Zero Flag is set,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setne:setnz
^SETNE/SETNZ - Set if Not Equal / Set if Not Zero (386+ only)


	Usage:	SETNE	dest
		SETNZ	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Zero Flag is clear,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setl:setnge
^SETL/SETNGE - Set if Less / Set if Not Greater or Equal
^(signed, 386+ only)


	Usage:	SETL	dest
		SETNGE	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Sign Flag is not equal
	to the Overflow Flag, otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setge:setnl
^SETGE/SETNL - Set if Greater or Equal / Set if Not Less
^(signed, 386+ only)


	Usage:	SETGE	dest
		SETNL	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Sign Flag equals the
	Overflow Flag, otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setle:setng
^SETLE/SETNG - Set if Less or Equal / Set if Not greater or Equal
^(signed, 386+ only)


	Usage:	SETLE	dest
		SETNG	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Zero Flag is set or the
	Sign Flag is not equal to the Overflow Flag,  otherwise sets the
	operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setg:setnle
^SETG/SETNLE - Set if Greater / Set if Not Less or Equal
^(signed, 386+ only)


	Usage:	SETG	dest
		SETNLE	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Zero Flag is clear or the
	Sign Flag equals to the Overflow Flag,	otherwise sets the operand
	to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:sets
^SETS - Set if Signed (386+ only)


	Usage:	SETS	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Sign Flag is set, otherwise
	sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setns
^SETNS - Set if Not Signed (386+ only)


	Usage:	SETNS	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Sign Flag is clear,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setc
^SETC - Set if Carry (386+ only)


	Usage:	SETC	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Carry Flag is set,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setnc
^SETNC - Set if Not Carry (386+ only)


	Usage:	SETNC	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Carry Flag is clear,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:seto
^SETO - Set if Overflow (386+ only)


	Usage:	SETO	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Overflow Flag is set,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setno
^SETNO - Set if Not Overflow (386+ only)


	Usage:	SETNO	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Overflow Flag is clear,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setp:setpe
^SETP/SETPE - Set if Parity / Set if Parity Even  (386+ only)


	Usage:	SETP	dest
		SETPE	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Parity Flag is set,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:setnp:setpo
^SETNP/SETPO - Set if No Parity / Set if Parity Odd (386+ only)


	Usage:	SETNP	dest
		SETPO	dest
	Modifies flags: none


	Sets the byte in the operand to 1 if the Parity Flag is clear,
	otherwise sets the operand to 0.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg8		  -	-     4	    3		  3
	mem8		  -	-     5	    4		  3


	- see ~Instruction Timing~

:sgdt
^SGDT - Store Global Descriptor Table (286+ privileged)


	Usage:	SGDT	dest
	Modifies flags: none


	Stores the Global Descriptor Table (~GDT~) Register into the
	specified operand.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	mem64		  -	11    9	    10		  5


	- see ~Instruction Timing~

:sidt
^SIDT - Store Interrupt Descriptor Table (286+ privileged)


	Usage:	SIDT	dest
	Modifies flags: none


	Stores the Interrupt Descriptor Table (IDT) Register into the
	specified operand.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	mem64		  -	12    9	    10		  5


	- see ~Instruction Timing~

:shr
^SHR - Shift Logical Right

	Usage:	SHR	dest,count
	Modifies flags: CF OF PF SF ZF (AF undefined)


	Shifts the destination right by "count" bits with zeroes shifted
	in on the left.  The Carry Flag contains the last bit shifted out.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,1		  2	2     3			  2
	mem,1		15+EA	7     7			 2-4   (W88=23+EA)
	reg,CL		 8+4n  5+n    3			  2
	mem,CL	      20+EA+4n 8+n    7			 2-4   (W88=28+EA+4n)
	reg,immed8	  -    5+n    3			  3
	mem,immed8	  -    8+n    7			 3-5


	- see ~Instruction Timing~

:shld:shrd
^SHLD/SHRD - Double Precision Shift (386+ only)


	Usage:	SHLD	dest,src,count
		SHRD	dest,src,count
	Modifies flags: CF PF SF ZF (OF,AF undefined)


	SHLD shifts "dest" to the left "count" times and the bit positions
	opened are filled with the most significant bits of "src".  SHRD
	shifts "dest" to the right "count" times and the bit positions
	opened are filled with the least significant bits of the second
	operand.  Only the 5 lower bits of "count" are used.


%					Clocks			Size
%	Operands	 	808x  286   386   486		Bytes

	reg16,reg16,immed8	 -     -     3	   2		  4
	reg32,reg32,immed8	 -     -     3	   2		  4
	mem16,reg16,immed8	 -     -     7	   3		  6
	mem32,reg32,immed8	 -     -     7	   3		  6
	reg16,reg16,CL		 -     -     3	   3		  3
	reg32,reg32,CL		 -     -     3	   3		  3
	mem16,reg16,CL		 -     -     7	   4		  5
	mem32,reg32,CL		 -     -     7	   4		  5


	- see ~Instruction Timing~

:sldt
^SLDT - Store Local Descriptor Table (286+ privileged)


	Usage:	SLDT	dest
	Modifies flags: none


	Stores the Local Descriptor Table (LDT) Register into the
	specified operand.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	2     2	    2		  3
	mem16		  -	2     2	    3		  5


	- see ~Instruction Timing~

:smsw
^SMSW - Store Machine Status Word (286+ privileged)


	Usage:	SMSW	dest
	Modifies flags: none


	Store Machine Status Word (~MSW~) into "dest".


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	2     10    2		  3
	mem16		  -	3     3	    3		  5


	- see ~Instruction Timing~

:stc
^STC - Set Carry


	Usage:	STC
	Modifies flags: CF


	Sets the Carry Flag to 1.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2	    2		  1


	- see ~Instruction Timing~

:std
^STD - Set Direction Flag


	Usage:	STD
	Modifies flags: DF


	Sets the Direction Flag to 1 causing string instructions to
	auto-decrement SI and DI instead of auto-increment.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2	    2		  1


	- see ~Instruction Timing~

:sti
^STI - Set Interrupt Flag  (Enable Interrupts)


	Usage:	STI
	Modifies flags: IF


	Sets the Interrupt Flag to 1, enabling recognition of all CPU
	hardware interrupts.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  2	2     2	    5		  1


	- see ~Instruction Timing~

:stos:stosb:stosw:stosd
^STOS - Store String  (Byte, Word or Doubleword)


	Usage:	STOS	dest
		STOSB
		STOSW
		STOSD
	Modifies flags: None


	Stores value in accumulator to location at ES:(E)DI (even if operand
	is given).  (E)DI is incremented/decremented based on the size of
	the operand (or instruction format) and the state of the Direction
	Flag.	Use with ~REP~ prefixes.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	dest		  11	3     4	    5		  1  (W88=15)


	- see ~Instruction Timing~

:str
^STR - Store Task Register (286+ privileged)


	Usage:	STR	dest
	Modifies flags: None


	Stores the current Task Register to the specified operand.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	2     2	    2		  3
	mem16		  -	3     2	    3		  5


	- see ~Instruction Timing~

:sub
^SUB - Subtract

	Usage:	SUB	dest,src
	Modifies flags: AF CF OF PF SF ZF


	The source is subtracted from the destination and the result is
	stored in the destination.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	16+EA	7     6	    3		 2-4  (W88=24+EA)
	reg,mem 	 9+EA	7     7	    2		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem,immed	17+EA	7     7	    3		 3-6  (W88=25+EA)
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:test
^TEST - Test For Bit Pattern

	Usage:	TEST	dest,src
	Modifies flags: CF OF PF SF ZF (AF undefined)


	Performs a logical ~AND~ of the two operands updating the flags
	register without saving the result.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     1	    1		  2
	reg,mem 	 9+EA	6     5	    1		 2-4  (W88=13+EA)
	mem,reg 	 9+EA	6     5	    2		 2-4  (W88=13+EA)
	reg,immed	  5	3     2	    1		 3-4
	mem,immed	11+EA	6     5	    2		 3-6
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~

:verr
^VERR - Verify Read (286+ protected)


	Usage:	VERR	src
	Modifies flags: ZF


	Verifies the specified segment selector is valid and is readable
	at the current privilege level.  If the segment is readable,
	the Zero Flag is set, otherwise it is cleared.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	14    10    11		  3
	mem16		  -	16    11    11		  5


	- see ~Instruction Timing~

:verw
^VERW - Verify Write (286+ protected)


	Usage:	VERW	src
	Modifies flags: ZF


	Verifies the specified segment selector is valid and is ratable
	at the current privilege level.  If the segment is writable,
	the Zero Flag is set, otherwise it is cleared.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg16		  -	14    15    11		  3
	mem16		  -	16    16    11		  5


	- see ~Instruction Timing~

:wait:fwait
^WAIT/FWAIT - Event Wait


	Usage:	WAIT
		FWAIT
	Modifies flags: None


	CPU enters wait state until the coprocessor signals it has finished
	it's operation.  This instruction is used to prevent the CPU from
	accessing memory that may be temporarily in use by the coprocessor.
	WAIT and FWAIT are identical.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  4	3     6+   1-3		  1


	- see ~Instruction Timing~

:wbinvd
^WBINVD - Write-Back and Invalidate Cache


	Usage:	WBINVD
	Modifies flags: None


	Flushes internal cache, then signals the external cache to write
	back current data followed by a signal to flush the external cache.

%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	none		  -	-     -     5		  2


	- see ~Instruction Timing~

:xchg
^XCHG - Exchange


	Usage:	XCHG	dest,src
	Modifies flags: None


	Exchanges contents of source and destination.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg		  4	3     3	    3		  2
	mem,reg 	17+EA	5     5	    5		 2-4  (W88=25+EA)
	reg,mem 	17+EA	5     5	    3		 2-4  (W88=25+EA)
	accum,reg	  3	3     3	    3		  1
	reg,accum	  3	3     3	    3		  1


	- see ~Instruction Timing~

:xlat:xlatb
^XLAT/XLATB - Translate


	Usage:	XLAT	translation-table
		XLATB	(masm 5.x)
	Modifies flags: None


	Replaces the byte in AL with byte from a user table addressed by
	BX.  The original value of AL is the index into the translate table.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	table		  11	5     5	    4		  1


	- see ~Instruction Timing~

:xor
^XOR - Exclusive OR

	Usage:	XOR	dest,src
	Modifies flags: CF OF PF SF ZF (AF undefined)


	Performs a bitwise exclusive OR of the operands and returns
	the result in the destination.


%				 Clocks			Size
%	Operands	 808x  286   386   486		Bytes

	reg,reg 	  3	2     2	    1		  2
	mem,reg 	16+EA	7     6	    3		 2-4  (W88=24+EA)
	reg,mem 	 9+EA	7     7	    2		 2-4  (W88=13+EA)
	reg,immed	  4	3     2	    1		 3-4
	mem,immed	17+EA	7     7	    3		 3-6  (W88=25+EA)
	accum,immed	  4	3     2	    1		 2-3


	- see ~Instruction Timing~