Programming Forums - View Single Post

liquidsilver · Mar 11th, 2005, 1:37 AM

I've just recently started with SMC (Self Modifying Code) and I'm having some problems:

.model tiny
.stack
.data
  key db 01h
.code
org 0100h

mov cx,3
StrLoop:
  dec cx
  mov di,(offset fix)
  add di,cx
  mov al,[di]
  xor al,key
  mov [di],al
  jcxz OutLoop
  jmp StrLoop
OutLoop:

fix db 0B9h, 036h, 003h ;mov ax,0237h
  ret
end main

This is my SMC.COM source. This works, but when I convert it to a EXE then it goes haywire. The correct data seems to not get targeted. I use MASM, please help.

Mar 11th, 2005, 1:37 AM	#1
liquidsilver Newbie Join Date: Mar 2005 Location: South Africa Posts: 21 Rep Power: 0	Self Modifying Code I've just recently started with SMC (Self Modifying Code) and I'm having some problems: (Toggle Plain Text) .model tiny .stack .data key db 01h .code org 0100h mov cx,3 StrLoop: dec cx mov di,(offset fix) add di,cx mov al,[di] xor al,key mov [di],al jcxz OutLoop jmp StrLoop OutLoop: fix db 0B9h, 036h, 003h ;mov ax,0237h ret end main .model tiny .stack .data key db 01h .code org 0100h mov cx,3 StrLoop: dec cx mov di,(offset fix) add di,cx mov al,[di] xor al,key mov [di],al jcxz OutLoop jmp StrLoop OutLoop: fix db 0B9h, 036h, 003h ;mov ax,0237h ret end main This is my SMC.COM source. This works, but when I convert it to a EXE then it goes haywire. The correct data seems to not get targeted. I use MASM, please help. __________________ Small is beautiful