MACHINE LANGUAGE ENCODER / x86

  Relative offset support for x86.


INSTALLATION

  # mkdir -p /usr/share/mle
  # cp -a x86 /usr/share/mle/


USAGE

  The following program illustrates the use of the 8-bit and 32-bit
  relative-offset calculators provided by the x86 plug-in.

  $ cat demo/echo.src
  [ . x86 ]

  Magic:
	90

  Start:
	# Quit if argc is less than or equal to 1.
	59					# pop rcx
	48 83 f9 01				# cmp 1 rcx
	7e [ rel8 Quit ]			# jle Quit

	# Skip argv[0].
	5e					# pop rsi

  Echo:
	# Quit if the next argument is NULL.
	5e					# pop rsi
	48 85 f6				# test rsi rsi
	7e [ rel8 Quit ]			# jz Quit

	# Otherwise, print it.
	e8 [ rel32 PrintString ]		# call PrintString

	# Print the separator.
	6a 01 5a				# mov 1 rdx
	48 8d 35 [ rel32 Separator ]		# lear Separator rsi
	e8 [ rel32 Print ]			# call Print

	# Continue.
	eb [ rel8 Echo ]			# jmp Echo

  PrintString:
	# Get the length of the string.
	48 89 f7				# mov rsi rdi
	48 31 c0				# xor rax rax
	48 31 c9				# xor rcx rcx
	48 ff c9				# dec rcx
	f2 ae					# repnz scasb
	48 89 ca				# mov rdx, rcx
	48 f7 d2				# not rdx
	48 ff ca				# dec rdx

  Print:
	# write(STDOUT_FILENO, buffer, length)
	6a 01 5f				# mov STDOUT_FILENO rdi
	6a 01 58				# mov SYS_WRITE rax
	0f 05					# syscall
	c3					# ret

  Quit:
	# Print the terminator.
	6a 01 5a				# mov 1 rdx
	48 8d 35 [ rel32 Terminator ]		# lear Terminator rsi
	e8 [ rel32 Print ]			# call Print

	# Exit.
	6a 00 5f				# mov EXIT_SUCCESS rdi
	6a 3c 58				# mov SYS_EXIT rax
	0f 05					# syscall

  Separator:
	20

  Terminator:
	0a


  $ mle < demo/echo.src > demo/echo
  $ chmod 755 demo/echo
  $ ls -al demo/echo
  -rwxr-xr-x 1 user input 94 Oct 15 12:30 demo/echo

  $ demo/echo take it or leave it
  take it or leave it 


SEE ALSO

  https://github.com/jhswartz/mle
  https://github.com/jhswartz/mli


AUTHOR

  Justin Swartz <justin.swartz@risingedge.co.za>