Introduction

This is a 16-Bit CPU architecture project, along with an assembler capable of accepting the commands listed below, separated by function within the programming.

The assembler is capable of converting from assembly to binary or hexadecimal; to use with Logisim it is necessary to convert to hexadecimal and place it inside the ROM memory that is in the main component.

OpCodes

Legend

• AAAA = Address of an A register
• BBBB = Address of an B register
• XXXX = Will be ignored
• CCCC CCCC = 8 bit C constant
• LLLL LLLL LLLL = Label used for jumps in 12-bit code

ULA

inst	OpCode	Description
and	1111 0000 AAAA BBBB	A = A & B
sub	1111 0001 AAAA BBBB	A = A - B
mult	1111 0010 AAAA BBBB	A = A * B
div	1111 0011 AAAA BBBB	A = A / B (Integer Division)
nand	1111 0100 AAAA BBBB	A = !(A & B)
rsh	1111 0101 AAAA BBBB	A = A >> B
xnor	1111 0110 AAAA BBBB	A = !(A ^ B)
inc	1111 0111 AAAA XXXX	A = A + 1
dec	1111 1000 AAAA XXXX	A = A - 1
xor	1111 1001 AAAA BBBB	A = A ^ B
not	1111 1010 AAAA BBBB	A = !A
nor	1111 1011 AAAA BBBB	A = !(A | B)
lsh	1111 1100 AAAA BBBB	A = A << B
add	1111 1101 AAAA BBBB	A = A + B
ivt	1111 1110 AAAA BBBB	A = -A
or	1111 1111 AAAA BBBB	A = A | B

Jumps

inst	OpCode	Description
jump	0001 LLLL LLLL LLLL	Jump
je	0010 LLLL LLLL LLLL	Jump if equal
jne	0011 LLLL LLLL LLLL	Jump if not equal
jg	0100 LLLL LLLL LLLL	Jump if greater than
jge	0101 LLLL LLLL LLLL	Jump if greater or equal
jz	0110 LLLL LLLL LLLL	Jump if last value is zero

Movs

inst	OpCode	Description
movcosnt	1000 AAAA CCCC CCCC	A = C
load	1001 0001 AAAA [BBBB]	A = *B
store	1001 0010 [AAAA] BBBB	*A = B
mov	1001 0011 AAAA BBBB	A = B
push	1001 0100 AAAA XXXX	Put value A on the stack
pop	1001 0101 AAAA XXXX	Remove value from stack

Compare

inst	OpCode	Description
cmp	1100 XXXX AAAA BBBB	Compare A with B
cmpcosnt	1110 AAAA CCCC CCCC	Compare A with C

Functions

inst	OpCode	Description
call	1010 LLLL LLLL LLLL	Call a function
ret	1011 XXXX XXXX XXXX	Return a function

Others

inst	OpCode	Description
nop	0000 XXXX XXXX XXXX	Does not do anything