xor in arithmetical expressions

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omega_red

Joined: 13 Mar 2004
Posts: 19
Location: Poland

omega_red 03 Oct 2004, 17:34

Code:

macro        call2   target
{
    push    (@f xor 0xdeadbeef)
 jmp     target
@@:
   add     esp, 4
}

This yields error: invalid expression.
However, if I replace xor with +, it compiles fine. It seems that compiler takes the xor as a cpu instruction, not operator. How to use the xor operator? Why it has the same form as an instruction, and not ^ like in C, for example?

_________________
Vulnerant omnes, ultima necat

03 Oct 2004, 17:34

Matrix

Joined: 04 Sep 2004
Posts: 1166
Location: Overflow

Matrix 03 Oct 2004, 17:47

omega_red wrote:

Code:
macro  call2   target
{
    push    (@f xor 0xdeadbeef)
 jmp     target
@@:
   add     esp, 4
}    
This yields error: invalid expression.
However, if I replace xor with +, it compiles fine. It seems that compiler takes the xor as a cpu instruction, not operator. How to use the xor operator? Why it has the same form as an instruction, and not ^ like in C, for example?

HY, these whould be interesting cause' for example on my hungarian keyboard < means delete line Sad

MATRIX

03 Oct 2004, 17:47

omega_red

Joined: 13 Mar 2004
Posts: 19
Location: Poland

omega_red 03 Oct 2004, 18:16

OK, I found that this is a relocation problem, not parser failure Wink

+ worked instead of xor because it does't have to know absolute address.

Code:

macro    call2   target
{
    local f
     f = BASE + RVA @f
   push    (f xor 0xdeadbeef)
  jmp     target
@@:
   add     esp, 4
}

03 Oct 2004, 18:16

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