Hi guys. What's wrong with mov reg, [EAX...] constructions ?
"error A2022: instruction operands must be the same size" is displayed in all cases we use "EAX" in the right part.
You're pointing to memory and therefore must specify what you want from it byte word dword
mov eax, dword ptr [eax]
mov ax, word ptr [eax]
mov al, byte ptr [eax]
Hello,
how about a real life example?
Quote from: Robert on November 09, 2005, 08:04:40 PM
Hi guys. What's wrong with mov reg, [EAX...] constructions ?
"error A2022: instruction operands must be the same size" is displayed in all cases we use "EAX" in the right part.
If you code:
mov dx, eax;The error is legitimate because you are trying to mov 32bit into a 16bit destination.
You must use a 32bit register as destination register in that case.
Also refer to the above post if you are dealing with pointers.
Take care on the size. Assembler is not happy about "implict things" :wink
:) thanks guys, but i'm not so lame in MASM...
look:
mov eax, [ebx+0Ch] ; no error
mov ecx, [edx*2+4] ; no error
mov ebx, [eax+4] ; error A2022!!!
understand? ;)
Quote from: Robert on November 09, 2005, 09:05:41 PM
look:
mov eax, [ebx+0Ch] ; no error
mov ecx, [edx*2+4] ; no error
mov ebx, [eax+4] ; error A2022!!!
understand? ;)
Thats why I asked for an example. Figuring something out isn´t really good...
BUT:
.386
.model flat, stdcall
option casemap:none
include \masm32\include\windows.inc
include \masm32\include\kernel32.inc
includelib kernel32.lib
include \masm32\include\user32.inc
includelib user32.lib
.data
MsgCaption db "Iczelion's tutorial no.2",0
MsgBoxText db "Win32 Assembly is Great!",0
.code
start:
push ebx
push eax
mov eax, offset MsgCaption
mov ebx, [eax+4]
pop eax
pop ebx
invoke MessageBox, NULL,addr MsgBoxText, addr MsgCaption, MB_OK
invoke ExitProcess,NULL
end start
The above example assembles, links and executes just fine...
Quote from: Robert on November 09, 2005, 09:05:41 PM
:) thanks guys, but i'm not so lame in MASM...
Really?
Regards
Holly Christ... It was my mistake... I've forgot 'bout
assume reg:nothing
before using
mov ..., [reg...] constructions.
nice nolame bug :)
Reggards.