I've some old TASM 5 sources which I would like to translate to MASM. That's mostly no problem, but the next code snippet is a bit tricky. Given the following structure for DPMI translation service:
regs STRUC
redi dd ? ;di or edi
resi dd ? ;si or esi
rebp dd ? ;bp or ebp
reserved dd 0 ;reserved, should be 0
rebx dd ? ;bx or ebx
redx dd ? ;dx or edx
recx dd ? ;cx or ecx
reax dd ? ;ax or eax
rflags dw ? ;CPU status flags
res dw ? ;es
rds dw ? ;ds
rfs dw ? ;fs
rgs dw ? ;gs
rip dw ? ;ip
rcs dw ? ;cs
rsp dw ? ;sp
rss dw ? ;ss
regs ENDS
I need that data structure only temporarily at the stack. With TASM I did it so:
SomeFunc proc near
@@regs = [ebp-50]
push ebp
mov ebp,esp
sub esp,50
;access structure member
mov @@regs.reax,eax
;load structure address
lea edi,@@regs
mov esp,ebp
pop ebp
ret
SomeFunc endp
MASM doesn't assemble that. Is there any simple solution?
Gunther
Define it as a LOCAL, and let MASM build the stack frame? Given me a second and I will try to code an example.
SomeFunc proc near c
LOCAL foo:regs
;access structure member
mov foo.reax,eax
;load structure address
lea edi,foo
ret
SomeFunc endp
Which generates this.. (note it keeps the stack DWORD aligned)
00000000 _SomeFunc:
00000000 55 push ebp
00000001 8BEC mov ebp,esp
00000003 83C4CC add esp,0FFFFFFCCh
00000006 8945EA mov [ebp-16h],eax
00000009 8D7DCE lea edi,[ebp-32h]
0000000C C9 leave
0000000D C3 ret
Something like this might also work.
SomeFunc proc near
push ebp
mov ebp,esp
sub esp,50
;access structure member
mov [ebp-50].regs.reax,eax
;load structure address
lea edi,[ebp-50]
mov esp,ebp
pop ebp
ret
SomeFunc endp
Clive,
you're a devil of a fellow! :U That helps me a lot. I'll try that immediately.
Gunther
Clive beat me to it, here's what I had come up with.
INCLUDE \masm32\include\masm32rt.inc
regs STRUCT
redi dd ? ;di or edi
resi dd ? ;si or esi
rebp dd ? ;bp or ebp
reserved dd 0 ;reserved, should be 0
rebx dd ? ;bx or ebx
redx dd ? ;dx or edx
recx dd ? ;cx or ecx
reax dd ? ;ax or eax
rflags dw ? ;CPU status flags
res dw ? ;es
rds dw ? ;ds
rfs dw ? ;fs
rgs dw ? ;gs
rip dw ? ;ip
rcs dw ? ;cs
rsp dw ? ;sp
rss dw ? ;ss
regs ENDS
.DATA
.CODE
start:
call SomeFunc
inkey "Press any key to exit..."
exit
SomeFunc PROC
LOCAL @@regs:regs
;access structure member
mov eax, 123
mov @@regs.reax, eax
INVOKE crt_printf, SADD("%u",13,10), @@regs.reax
;load structure address
lea edi, @@regs
INVOKE crt_printf, SADD("%p",13,10), edi
ret
SomeFunc ENDP
END start
Dissassembly:
SomeFunc PROC
00401035 push ebp
00401036 mov ebp,esp
00401038 add esp,0FFFFFFCCh
LOCAL @@regs:regs
;access structure member
mov eax, 123
0040103B mov eax,7Bh
mov @@regs.reax, eax
00401040 mov dword ptr [ebp-16h],eax
INVOKE crt_printf, SADD("%u",13,10), @@regs.reax
00401043 push dword ptr [ebp-16h]
00401046 push offset ??001C (40401Ch)
0040104B call dword ptr [__imp__printf (405104h)]
00401051 add esp,8
;load structure address
lea edi, @@regs
00401054 lea edi,[@@regs]
00401057 push edi
00401058 push offset ??001D (404024h)
0040105D call dword ptr [__imp__printf (405104h)]
00401063 add esp,8
INVOKE crt_printf, SADD("%p",13,10), edi
00401066 leave
00401067 ret
SomeFunc ENDP
Quote from: GregL, September 16, 2010, at 02:49:12 AM... here's what I had come up with.
Well done.
Gunther