interfacing assembler with c++

Can anyone clear up the proper syntax for calling assembler code from within a c or c++ program? I am using masm 6.00 and VC ver 1 (both 16 bit and both using the medium memory model) I want to expand on this basic example, but I can't seem to get it to work. Both the c program and the assembler program compile to obj files without errors. Link builds the exe from both obj files without any reported errors; however, when run, the program goes into lala land. TIA

masm

.MODEL MEDIUM, C
.STACK
.CODE
.STARTUP

PUBLIC set_mode
set_mode PROC FAR C vmode:WORD

mov ah,0
mov al, BYTE PTR vmode
int 10h
ret
set_mode ENDP
END

c source

#include <stdio.h>
#define MODE13 0x13

extern set_mode(int);

void main()
{
blah blah
set_mode(MODE13);
blah blah
}

You compile it as a DOS app right?

You should do something like this, but I don't know have masm

and vc++.



First write the .h file. Fill in the prototypes to all the functions

your going to write in assembly. Look up some documentation

on vc++ calling order and name mangling, or you could write c++ stubs then compile into assembly. The calling convention is most likely to push the arguments from right to left. Then the return adress (eip+1) is pushed by the call instruction.



For linux on intel, I end up with code which looks similar to



f:

; linux c calling convention is that edi, esi, ebp, esp must be

; kept intact

push ebp

mov ebp, esp



sub esp, 4 ; create a local variable



; ints are four bytes

mov ebx, [ebp+8] ; first argument

mov ebx, [ebp+12] ; second argument

mov dword [ebp-4], 4h ; assign 4h to local variable



; leave does this

; mov esp, ebp

; pop ebp


leave

ret



for this function



void f(int a, int b);