proc quirk in ML64

[hutch--]

With so little information available, this stuff comes by experiment but surprisingly enough the old form of procedure declaration partially works in that it will accept a sequence of arguments with the data size specified as it was done in Win32. The difference is the first 4 arguments are left blank, args 5 onwards are stored on the stack and occur in the right location in RBP. If you copy the 4 registers rcx, rdx, r8 and r9 into the first 4 arguments everything works correctly. Below is a WndProc example that works fine.

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WndProc proc hWin:QWORD,uMsg:QWORD,wParam:QWORD,lParam:QWORD

    mov QWORD PTR [rbp+10h], rcx
    mov QWORD PTR [rbp+18h], rdx
    mov QWORD PTR [rbp+20h], r8
    mov QWORD PTR [rbp+28h], r9

    .switch uMsg

      .case WM_COMMAND
        .switch wParam
          .case 1000
            void(SendMessage,hWin,WM_SYSCOMMAND,SC_CLOSE,NULL)

          .case 10000
            fn MessageBox, \
                         hWin, \
                         "Example with icon, menu and manifest.", \
                         "About ML64 Example", \
                         MB_OK
        .endsw

      .case WM_CLOSE
        fn MessageBox, \
                     hWin, \
                     "Sending the WM_DESTROY message.", \
                     "WM_CLOSE here", \
                     MB_OK

        void(SendMessage,hWin,WM_DESTROY,0,0)

      .case WM_DESTROY
        void(PostQuitMessage,NULL)

    .endsw

    void(DefWindowProc,hWin,uMsg,wParam,lParam)

    ret

WndProc endp

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[jj2007]

It's hard stuff. What helped me a lot was to ask GCC for help, see below 8)

Code Select Expand

#include <stdio.h>
#include <windows.h>
int main() {
  float f=111.111;
  double d=222.222;
  char* wfjj="This is a test string for output";
// OPT_Susy Console ; put an x for seeing output to the right, no x for use with _getch()
  printf("args:\n%i\t%f\t%f\t%i\t%f\n", 0x111, f, d, 0x444, 555.555); // GCC
  return MessageBox(0, "printf succeeded?", "Hi Jochen:", MB_YESNO | MB_ICONINFORMATION);
}

#if 0
40152F  | 90                      | nop
401530  | 48 83 EC 38             | sub rsp, 38
401534  | E8 E7 0B 00 00          | call tmp.40    | ?? sets a global dword flag
401539  | F2 0F 10 0D 07 2B 00 00 | movsd xmm1, qword ptr ds:[404038]  | d 222
401541  | F2 0F 10 05 07 2B 00 00 | movsd xmm0, qword ptr ds:[404040]  | f 111
401549  | C7 44 24 20 44 04 00 00 | mov dword ptr ss:[rsp+20], 444     | 5th arg
xxxxxx  | F2 0F 10 25 F7 2A 00 00 | movsd xmm4, qword ptr ds:[404048]  | 555.555
xxxxxx  | F2 0F 11 64 24 28       | movsd qword ptr ss:[rsp+28], xmm4  | 6th arg
401551  | 66 0F 28 D9             | movapd xmm3, xmm1
401555  | 66 49 0F 7E C9          | movq r9, xmm1
40155A  | 66 0F 28 D0             | movapd xmm2, xmm0
40155E  | 66 49 0F 7E C0          | movq r8, xmm0
401563  | BA 11 01 00 00          | mov edx, 111
401568  | 48 8D 0D 91 2A 00 00    | lea rcx, qword ptr ds:[404000]     | 404000:"args:\n%i\t%f\t%f\t%i\n"
40156F  | E8 C4 15 00 00          | call <tmp.printf>
401574  | 41 B9 44 00 00 00       | mov r9d, 44
40157A  | 4C 8D 05 AA 2A 00 00    | lea r8, qword ptr ds:[40402B]
401581  | 48 8D 15 AE 2A 00 00    | lea rdx, qword ptr ds:[404036]
401588  | B9 00 00 00 00          | mov ecx, 0
40158D  | FF 15 2D 6E 00 00       | call qword ptr ds:[<&MessageBoxA>]
401593  | 48 83 C4 38             | add rsp, 38
401597  | C3                      | ret


402120  | 8B 05 1A 52 00 00       | mov eax, dword ptr ds:[407340]     |
402126  | 85 C0                   | test eax, eax                      |
402128  | 74 06                   | je tmp.402130                      |
40212A  | F3 C3                   | ret                                |

#endif

[sinsi]

How does this go?

Code Select Expand


    mov hWin, rcx    ;instead of mov QWORD PTR [rbp+10h], rcx

Might as well use the name.

[hutch--]

Its so you can use the same 4 lines of code in any multi-argument procedure. Names change where the address does not.