How to do these

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l4m2

Joined: 15 Jan 2015
Posts: 674

l4m2 26 Jan 2015, 03:24

make a macro:
mov eax,ebx => mov eax,ebx
mov eax,ebx+ecx => lea eax,[ebx+ecx]
mov ax,[bx+cx] => lea ax,[ebx+ecx] ;May be harder somehow
mov dword [eax],[ebx] => push dword [ebx]|pop dword [eax]
So how many of them can be done?
Mov ax,[ebx+ecx] can be used to replace the third command
I think there should be some ways to know if a command is illegal ...

26 Jan 2015, 03:24

RIxRIpt

Joined: 18 Apr 2013
Posts: 50

RIxRIpt 26 Jan 2015, 12:06

2.2.2 Conditional assembly

Quote:

The eqtype operator checks whether the two compared values have the same structure, ...

Code:

use32

macro mov op1, op2 {
        if op2 eqtype eax+eax
                lea op1, [op2]
        else if op1 eqtype dword[eax] & op2 eqtype [eax]
                push dword op2
                pop op1
        else ;the rest cases you could do your self..
                mov op1, op2
        end if
}

mov eax, ebx + ecx
mov eax, ebx
mov edx, esi + edi
mov dword[edi], [esi]

;compiles to:
CPU Disasm
Address   Hex dump          Command
00CA2FF0    8D040B          LEA EAX,[ECX+EBX]
00CA2FF3    89D8            MOV EAX,EBX
00CA2FF5    8D143E          LEA EDX,[EDI+ESI]
00CA2FF8    FF36            PUSH DWORD PTR DS:[ESI]
00CA2FFA    8F07            POP DWORD PTR DS:[EDI]

26 Jan 2015, 12:06

l4m2

Joined: 15 Jan 2015
Posts: 674

l4m2 26 Jan 2015, 13:22

RIxRIpt wrote:

2.2.2 Conditional assembly

Quote:

The eqtype operator checks whether the two compared values have the same structure, ...

Code:

use32

macro mov op1, op2 {
        if op2 eqtype eax+eax
                lea op1, [op2]
        else if op1 eqtype dword[eax] & op2 eqtype [eax]
                push dword op2
                pop op1
        else ;the rest cases you could do your self..
                mov op1, op2
        end if
}

mov eax, ebx + ecx
mov eax, ebx
mov edx, esi + edi
mov dword[edi], [esi]

;compiles to:
CPU Disasm
Address   Hex dump          Command
00CA2FF0    8D040B          LEA EAX,[ECX+EBX]
00CA2FF3    89D8            MOV EAX,EBX
00CA2FF5    8D143E          LEA EDX,[EDI+ESI]
00CA2FF8    FF36            PUSH DWORD PTR DS:[ESI]
00CA2FFA    8F07            POP DWORD PTR DS:[EDI]

But can it know "lea eax,[eax*4+ecx]"?Infinity ways to mean so.

26 Jan 2015, 13:22

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