Question

I am writing an assignment in MASM32 Assembly and I almost completed it but I have 2 questions I can’t seem to answer. First, when I compile I get the message:

INVOKE requires prototype for procedure

&

invalid instruction operands

the first is due to this piece of code:

.data? Freq    DWORD ? Time1   DWORD ? Time2   DWORD ?  .code start: invoke QueryPerformanceFrequency, addr Freq invoke QueryPerformanceCounter, addr Time1  

now, I know that

The INVOKE directive must be preceded by a PROTO statement for the procedure being called.

but even though I found out the syntax for the PROTO statement:

label PROTO [distance] [langtype] [,[parameter]:tag] 

I don’t understand exactly what I should write so as to make it work and I don’t even know what is causing the second error or how to fix it…=/

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Edit

I already have those libraries and these also:

.386 .model flat, stdcall option casemap :none  include \masm32\include\windows.inc include \masm32\include\kernel32.inc include \masm32\include\masm32.inc includelib \masm32\lib\kernel32.lib includelib \masm32\lib\masm32.lib 

I’m working under Windows Vista just in case that helps as well.

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Edit 2

If I write the Freq :QWORD after the .data I get this error message:

use of register assumed to ERROR

and also where should I add the

QueryPerformanceCounter PROTO :DWORD 

Which as far as I know didn’t make an error but still I’m not sure changed anything (I placed it before .data and after the libraries).

Answer 1

In order to call an external API you need to include the appropriate *.inc file as well as the respective *.lib file.
Try to add these statements to your listing:

include \masm32\include\kernel32.inc includelib \masm32\lib\kernel32.lib 

(assuming \masm32 referes to your masm32 dir)

Update:
The prototype definition basically tells the assembler how many parameters the respective function expects on the stack. In your case the API expects one 32bit parameter to be on the stack, which is reflected by the prototype like this:

QueryPerformanceCounter PROTO :DWORD 

Update2:
In order to use the performance counter API you need a quadword. The reason is, that the API expects a pointer to a quadword (64 bit) as the parameter (therefore the DWORD in the prototype):

LOCAL Freq  :QWORD invoke QueryPerformanceFrequency, ADDR Freq 

This should do the trick.

Update3:
So here’s a complete example which works for me:

    .486     .model flat, stdcall     option casemap :none      include \masm32\include\windows.inc     include \masm32\include\kernel32.inc     include \masm32\include\masm32.inc      includelib \masm32\lib\kernel32.lib     includelib \masm32\lib\masm32.lib      doPerf     PROTO  .code  start:      invoke doPerf     invoke ExitProcess,eax      doPerf proc          LOCAL Freq  :QWORD         invoke QueryPerformanceFrequency, ADDR Freq         mov esi, dword ptr Freq         mov edi, dword ptr Freq+4          ret      doPerf endp  end start  

I guess that’s it 🙂 ESI and EDI now contain the result.