Hi
Today I stumped on a strange behaviour of "equ". The code looks like
.xmm
option casemap:none
option dotname
option frame:auto
option win64:8
option stackbase:rsp
.code
WinTest_Startup proc Arg1:QWORD
ret
WinTest_Startup endp
WinStart equ WinTest_Startup
start proc
invoke WinTest_Startup, 123
invoke WinStart, 123
ret
start endp
end start
and compiled with uasm64 2.49.0.2:
00007FF799371001 48 83 EC 28 sub rsp,28h
00007FF799371005 48 C7 C1 7B 00 00 00 mov rcx,7Bh
00007FF79937100C E8 EF FF FF FF call 00007FF799371000
00007FF799371011 6A 7B push 7Bh
00007FF799371013 E8 E8 FF FF FF call 00007FF799371000
00007FF799371018 48 83 C4 28 add rsp,28h
00007FF79937101C C3 ret
You can see, that the second invoke can be performed without problems, but uasm seems to think that a different calling convention should be used.
If we replace the "equ" directive with "textequ" or "equ <WinTest_Startup>", everthing will work again.
I think we have a "feature" here that needs some attention.
Biterider
Hi Biterider :biggrin:
If you use WinStart = WinTest_Startup instead of WinStart equ WinTest_Startup it will work
It will work as well if you use WinStart equ WinTest_Startup before .code section
In WinStart = WinTest_Startup equate sign is an assembly time directive and it uses different approach
In WinStart equ WinTest_Startup EQU is a Constant directive so if used inside .code, text must be inside <> brackets.
To get better idea how it works you can look up equate.c source in UASM folder
.xmm
option casemap:none
option dotname
option frame:auto
option win64:8
option stackbase:rsp
WinStart equ WinTest_Startup
.code
WinTest_Startup proc Arg1:QWORD
ret
WinTest_Startup endp
start proc
invoke WinTest_Startup, 123
invoke WinStart, 123
ret
start endp
end start
If I recoil correctly, we had discussion about EQU inside .code section long time ago somewhere in this forum
However, it is very interesting "feature" of UASM of which we have to be aware :smiley:
BTW I suggest to use option win64:11 instead of option win64:8
and if you want 16 byte data aligned use option win64:15
/* flags for win64_flags */
enum win64_flag_values {
W64F_SAVEREGPARAMS = 0x01, /* 1=save register params in shadow space on proc entry */
W64F_AUTOSTACKSP = 0x02, /* 1=calculate required stack space for arguments of INVOKE */
W64F_STACKALIGN16 = 0x04, /* 1=stack variables are 16-byte aligned; added in v2.12 */
W64F_SMART = 0x08, /* 1=takes care of everything */
W64F_HABRAN = W64F_SAVEREGPARAMS | W64F_AUTOSTACKSP | W64F_SMART,
W64F_ALL = W64F_SAVEREGPARAMS | W64F_AUTOSTACKSP | W64F_STACKALIGN16 | W64F_SMART, /* all valid flags */
};
Hi habran
Thanks for the clarification.
My point is, that it is a bit strange that you can use "equ" and make an invoke with the new symbol, but the calling convention changed.
I checked what happened using ML 6.15 in 32 bit. It accepts the code, compiles and executes correctly as expected.
option casemap:none ;Case sensitive
option dotname ;Enable dot names
.686p ;Use 686 protected mode
.model flat, stdcall
.code
WinTest_Startup proc Arg1:DWORD
ret
WinTest_Startup endp
WinStart equ WinTest_Startup
start proc
invoke WinTest_Startup, 123
invoke WinStart, 123
ret
start endp
end start00781000 55 push ebp
00781001 8B EC mov ebp,esp
00781003 C9 leave
00781004 C2 04 00 ret 4
00781007 6A 7B push 7Bh
00781009 E8 F2 FF FF FF call 00781000
0078100E 6A 7B push 7Bh
00781010 E8 EB FF FF FF call 00781000 QuoteBTW I suggest to use option win64:11 instead of option win64:8
and if you want 16 byte data aligned use option win64:15
Thank you very much. I have read the manual again and have now switched to win64: 15.
I was wrong in believing that "W64F_SMART = 0x08, // 1 = takes care of everything (Uasm)" really takes care of everything :cool:
Regards, Biterider