Hi :tongue:,
the following code breaks the stack -
; Some funcs below are decorated as __cdecl
; but pop arguments from the stack.
_alldiv PROTO C :DWORD, :DWORD, :DWORD, :DWORD
_allmul PROTO C :DWORD, :DWORD, :DWORD, :DWORD
;EXTRN _ltod3:PROC
.data
.code
mainCRTStartup proc
tv165 = -8
push ebp
mov ebp, esp
sub esp, 8
invoke QueryPerformanceFrequency, addr TimeFrequency
invoke QueryPerformanceCounter, addr TimeEnd
mov ecx, DWORD PTR TimeEnd
sub ecx, DWORD PTR TimeStart
mov eax, DWORD PTR TimeEnd+4
sbb eax, DWORD PTR TimeStart+4
invoke _allmul, ecx, eax, 1000000000, 0
invoke _alldiv, eax, edx, DWORD PTR TimeFrequency, DWORD PTR TimeFrequency+4
mov ecx, eax
mov DWORD PTR TimeElapsed, eax
mov DWORD PTR TimeElapsed+4, edx
;call _ltod3
movsd QWORD PTR tv165[ebp], xmm0
fld QWORD PTR tv165[ebp]
mov esp, ebp
pop ebp
ret 0
ret
mainCRTStartup endp
after compilation, the code looks like this ..
PUSH 0
PUSH 3B9ACA00
PUSH EAX
PUSH ECX
CALL <test_20200525_123708.__allmul>
ADD ESP, 10
PUSH DWORD PTR DS:[403118]
PUSH DWORD PTR DS:[<_TimeFrequency>]
PUSH EDX
PUSH EAX
CALL <test_20200525_123708.__alldiv>
ADD ESP, 10
The important line is - ADD ESP, 10
If you look at ntdll ...
778F57F0 <ntdll._allmul> | 8B4424 08 | MOV EAX, DWORD PTR SS:[ESP + 8] |
778F57F4 | 8B4C24 10 | MOV ECX, DWORD PTR SS:[ESP + 10] |
778F57F8 | 0BC8 | OR ECX, EAX |
778F57FA | 8B4C24 0C | MOV ECX, DWORD PTR SS:[ESP + C] |
778F57FE | 75 09 | JNE ntdll.778F5809 |
778F5800 | 8B4424 04 | MOV EAX, DWORD PTR SS:[ESP + 4] |
778F5804 | F7E1 | MUL ECX |
778F5806 | C2 1000 | RET 10 |
778F5809 | 53 | PUSH EBX |
778F580A | F7E1 | MUL ECX |
778F580C | 8BD8 | MOV EBX, EAX |
778F580E | 8B4424 08 | MOV EAX, DWORD PTR SS:[ESP + 8] |
778F5812 | F76424 14 | MUL DWORD PTR SS:[ESP + 14] |
778F5816 | 03D8 | ADD EBX, EAX |
778F5818 | 8B4424 08 | MOV EAX, DWORD PTR SS:[ESP + 8] |
778F581C | F7E1 | MUL ECX |
778F581E | 03D3 | ADD EDX, EBX |
778F5820 | 5B | POP EBX |
778F5821 | C2 1000 | RET 10 |
The important line is - 778F5821 | C2 1000 | RET 10
How to fix this broken stack situation?
Possible solutions:
1. direct call
2. without prototype
3. custom call macro
4. sub esp, 10h
How can we get around such a dirty style?
deleted
Ya,
ADD ESP, 10
wrong size, or wrong unsigned conversion, it must be hexadecimal 0x10 or decimal 16
invoke.c
if ((sym->langtype == LANG_C || sym->langtype == LANG_SYSCALL) &&
(info->parasize || (info->has_vararg && size_vararg))) {
if (info->has_vararg) {
DebugMsg1(("InvokeDir: size of fix args=%u, var args=%u\n", info->parasize, size_vararg));
AddLineQueueX(" add %r, %u", stackreg[ModuleInfo.Ofssize], NUMQUAL info->parasize + size_vararg);
}
else
AddLineQueueX(" add %r, %u", stackreg[ModuleInfo.Ofssize], NUMQUAL info->parasize);
}
Quote from: KradMoonRa on May 25, 2020, 10:05:27 PM
Ya,
ADD ESP, 10
wrong size, or wrong unsigned conversion, it must be hexadecimal 0x10 or decimal 16
invoke.c
if ((sym->langtype == LANG_C || sym->langtype == LANG_SYSCALL) &&
(info->parasize || (info->has_vararg && size_vararg))) {
if (info->has_vararg) {
DebugMsg1(("InvokeDir: size of fix args=%u, var args=%u\n", info->parasize, size_vararg));
AddLineQueueX(" add %r, %u", stackreg[ModuleInfo.Ofssize], NUMQUAL info->parasize + size_vararg);
}
else
AddLineQueueX(" add %r, %u", stackreg[ModuleInfo.Ofssize], NUMQUAL info->parasize);
}
Hi KradMoonRa,
everything seems to be right, the debugger displays numbers like this :icon_idea:
Quote from: nidud on May 25, 2020, 09:50:11 PM
Inline C functions like _alldiv (https://github.com/nidud/asmc/blob/master/source/lib32/math/alldiv.asm#L54) and _allmul (https://github.com/nidud/asmc/blob/master/source/lib32/math/allmul.asm#L30) used by the compiler are C functions that cleans up the stack (STDCALL without decoration).
INVOKE cant handle that so you have to use PUSH and CALL.
Hi nidud,
I thought we could somehow redefine the prototype or automatically generate a stub function ..
Quote from: nidud on May 25, 2020, 09:50:11 PM
Inline C functions like _alldiv (https://github.com/nidud/asmc/blob/master/source/lib32/math/alldiv.asm#L54) and _allmul (https://github.com/nidud/asmc/blob/master/source/lib32/math/allmul.asm#L30) used by the compiler are C functions that cleans up the stack (STDCALL without decoration).
INVOKE cant handle that so you have to use PUSH and CALL.
What exactly is the problem? crt_printf is C VARARG afaik...
include \Masm32\MasmBasic\Res\JBasic.inc ; ## builds in 32- or 64-bit mode with UAsm, ML, AsmC ##
usedeb=1 ; use the deb macro
Init ; OPT_64 1 ; put 0 for 32 bit, 1 for 64 bit assembly
PrintLine Chr$("This program was assembled with ", @AsmUsed$(1), " in ", jbit$, "-bit format.")
deb 4, "Stack", x:rsp
Print Str$("VarArg test:\t%i %i %i\n", 12, 13, 14)
deb 4, "Stack", x:rsp
jinvoke crt_printf, Chr$("VarArg test:", 9, "%i %i %i", 13, 10), 12, 13, 14
deb 4, "Stack", x:rsp
jinvoke MessageBox, 0, Chr$("Wow, it works!!!!"), Chr$("Test:"), MB_OK
EndOfCodeOutput:
This program was assembled with UAsm64 in 64-bit format.
Stack x:rsp 12ff00h
VarArg test: 12 13 14
Stack x:rsp 12ff00h
VarArg test: 12 13 14
Stack x:rsp 12ff00h
This program was assembled with ml64 in 64-bit format.
Stack x:rsp 12ff00h
VarArg test: 12 13 14
Stack x:rsp 12ff00h
VarArg test: 12 13 14
Stack x:rsp 12ff00h
deleted
Hi LiaoMi,
Could you try the code below? It should solve your stack problem :
include \masm32\include\masm32rt.inc
EXTERN _allmul:PROC
.data
.code
start:
invoke pr4 PTR _allmul,10,20,30,40
invoke ExitProcess,0
END start
Reading \masm32\include\windows.inc :
ArgCount MACRO number
LOCAL txt
txt equ <typedef PROTO :DWORD>
REPEAT number - 1
txt CATSTR txt,<,:DWORD>
ENDM
EXITM <txt>
ENDM
pr0 typedef PROTO
pr1 ArgCount(1)
pr2 ArgCount(2)
pr3 ArgCount(3)
pr4 ArgCount(4)
deleted
deleted
Hi nidud,
allmul typedef proto :qword, :qword
extern _allmul:ptr allmul
Thanks but this declaration will not work here assuming that _allmul is a member of a static library. Here is a quick example :
MsgBox.asm :
include \masm32\include\masm32rt.inc
PUBLIC Mbox
.code
Mbox:
invoke MessageBox,0,DWORD PTR [esp+12],\
DWORD PTR [esp+12],MB_OK
ret 2*4
END
Test.asm :
include \masm32\include\masm32rt.inc
EXTERN Mbox:PROC
.data
msg db 'This is a test.',0
capt db 'Hello',0
.code
start:
invoke pr2 PTR Mbox,ADDR msg,ADDR capt
invoke ExitProcess,0
END start
invoke pr2 PTR Mbox assembled to :
push offset capt
push offset msg
call _Mbox
Trying this one :
include \masm32\include\masm32rt.inc
mb TYPEDEF PROTO :DWORD,:DWORD
EXTERN Mbox:PTR mb
.data
msg db 'This is a test.',0
capt db 'Hello',0
.code
start:
invoke Mbox,ADDR msg,ADDR capt
invoke ExitProcess,0
END start
invoke Mbox assembled to :
push offset capt
push offset msg
call dword ptr [_Mbox]
call dword ptr [_Mbox] will lead to an application crash. Same problem with the definition extern _allmul:ptr allmul
Quote from: Vortex on May 26, 2020, 01:28:29 AM
Hi LiaoMi,
Could you try the code below? It should solve your stack problem :
include \masm32\include\masm32rt.inc
EXTERN _allmul:PROC
.data
.code
start:
invoke pr4 PTR _allmul,10,20,30,40
invoke ExitProcess,0
END start
Reading \masm32\include\windows.inc :
ArgCount MACRO number
LOCAL txt
txt equ <typedef PROTO :DWORD>
REPEAT number - 1
txt CATSTR txt,<,:DWORD>
ENDM
EXITM <txt>
ENDM
pr0 typedef PROTO
pr1 ArgCount(1)
pr2 ArgCount(2)
pr3 ArgCount(3)
pr4 ArgCount(4)
Hi Vortex,
great, thanks, this method works just fine :thumbsup: exactly what i needed :eusa_dance:
Quote from: nidud on May 26, 2020, 01:23:04 AM
Quote from: LiaoMi on May 25, 2020, 11:17:35 PM
Hi nidud,
I thought we could somehow redefine the prototype or automatically generate a stub function ..
They are made this way to prohibit people like you from using them, so don't use them. They are only there for internal use by the compiler.
Intended usage:
a = b / c * d;
You're right, there is a certain risk, but it seems to me that this function is very stable. "We can call everything from assembler :biggrin:" - this is my tactic.
Quote from: nidud on May 26, 2020, 02:00:08 AM
Quote from: Vortex on May 26, 2020, 01:28:29 AM
include \masm32\include\masm32rt.inc
EXTERN _allmul:PROC
.data
.code
start:
invoke pr4 PTR _allmul,10,20,30,40
invoke ExitProcess,0
END start
You may do this directly:
allmul typedef proto :qword, :qword
extern _allmul:ptr allmul
invoke _allmul,10,20
test.asm(93) : Error A2143: Symbol redefinition: _allmul - didn't work here :undecided:
Hi LiaoMi,
QuoteHi test.asm(93) : Error A2143: Symbol redefinition: _allmul - didn't work here
It looks like that _allmul is defined more than one time in your project. Maybe two external declarations. Could you check your project?
The macro below should work for you :
include \masm32\include\masm32rt.inc
EXTERN _allmul:PROC
_invoke MACRO p:REQ,args:VARARG
LOCAL counter
counter=0
FOR param,<args>
counter=counter+1
ENDM
IF counter EQ 0
call p
ELSE
FuncProto TYPEDEF @CatStr(<pr>,%counter)
invoke FuncProto PTR p,args
ENDIF
ENDM
.data
.code
start:
_invoke _allmul,10,20,30,40
invoke ExitProcess,0
END start
Quote from: Vortex on May 26, 2020, 04:03:14 AM
Hi LiaoMi,
QuoteHi test.asm(93) : Error A2143: Symbol redefinition: _allmul - didn't work here
It looks like that _allmul is defined more than one time in your project. Maybe two external declarations. Could you check your project?
The macro below should work for you :
include \masm32\include\masm32rt.inc
EXTERN _allmul:PROC
_invoke MACRO p:REQ,args:VARARG
LOCAL counter
counter=0
FOR param,<args>
counter=counter+1
ENDM
IF counter EQ 0
call p
ELSE
FuncProto TYPEDEF @CatStr(<pr>,%counter)
invoke FuncProto PTR p,args
ENDIF
ENDM
.data
.code
start:
_invoke _allmul,10,20,30,40
invoke ExitProcess,0
END start
Thanks, really one of the definitions was additionally active :azn: but the call as mentioned above does not work anyway:
PUSH 0
PUSH 3B9ACA00
PUSH EAX
PUSH ECX
CALL DWORD PTR DS:[<__allmul>]
The first macro is more readable. Thanks for the tips! :thup: :thup: :thup:
deleted
Hi nidud,
The static library assumption was based on your math class function :
https://github.com/nidud/asmc/blob/master/source/lib32/math/allmul.asm#L30
_allmul is for internal usage but similar stdcall functions with no decoration can be technically members of static \ dynamic libraries. A macro handling those functions can do the job.
deleted
Hi nidud,
Thanks for explaining Watcall, I didn't knew this calling convention.
QuoteWatcall is FASTCALL using EAX, ECX, EDX, and EBX
Regarding Watcall, the fifth and the further parameters are passed to the stack, is that correct? Another variant of my custom invoke macro could handle Watcall.
Edit :
QuoteWatcom compiler
The Watcom compiler doesn't conform to the register usage conventions in table 4. The
only scratch register is EAX. All other general purpose registers are callee-save, except for
EBX, ECX, EDX when used for parameter transfer, and ESI when used for return pointer. (In
16-bit mode, ES is also a scratch register). It is possible to specify any other register usage
by the use of pragmas in the Watcom compiler.
https://www.agner.org/optimize/calling_conventions.pdf
deleted
Hi nidud,
QuoteI haven't "released" any of these FASTCALL conventions in 32-bit as done in 64.
Maybe I am missing something, Asmc supports the standard fastcall convention in 32-bit :
; Source code assembled with
; Asmc Macro Assembler Version 2.31.30
.386
.model flat,stdcall
option casemap:none
includelib "\asmc-master\lib\kernel32.lib"
includelib "\asmc-master\lib\msvcrt.lib"
ExitProcess PROTO :DWORD
printf PROTO C :DWORD,:VARARG
.data
string1 db '10 + 20 + 30 + 40 = %d',0
.code
fcallproc PROC FASTCALL a:DWORD,b:DWORD,c:DWORD,d:DWORD
mov eax,a
add eax,b
add eax,c
add eax,d
ret
fcallproc ENDP
start:
invoke fcallproc,10,20,30,40
invoke printf,ADDR string1,eax
invoke ExitProcess,0
END startDisassembling the object module :
_text SEGMENT DWORD PUBLIC 'CODE'
@fcallproc@16 PROC NEAR
push ebp
mov ebp, esp
mov eax, ecx
add eax, edx
add eax, dword ptr [ebp+8H]
add eax, dword ptr [ebp+0CH]
leave
ret 8
@fcallproc@16 ENDP
_start PROC NEAR
push 40
push 30
mov edx, 20
mov ecx, 10
call @fcallproc@16
push eax
push offset _string1
call _printf
add esp, 8
push 0
call _ExitProcess@4
_start ENDP
_text ENDS
deleted