Q39309: Example of C Calling a MASM Procedure

Article: Q39309
Product(s): See article
Version(s): 5.10   | 5.10
Operating System(s): MS-DOS | OS/2
Keyword(s): ENDUSER | h_masm | mspl13_c
Last Modified: 29-DEC-1988

The sample code below demonstrates a C program calling a MASM
procedure. The C code declares an integer and passes the integer to
the MASM procedure called mixed(). The mixed() function has an integer
return value. The C code is compiled in the large-memory model and the
MASM code is assembled with the /ML option.

The following is the code:

#include <stdio.h>

int retval, value, foo;
extern int mixed(int);

main() {
    value = 35;
    foo = 25;
    retval = 0;
    retval = mixed(foo);
    printf("%d\n%d\n",retval,value);
    }

      DOSSEG
      .MODEL LARGE C
      .STACK  100h
      .DATA
        Dw 0
      .FARDATA
        EXTRN _value:WORD
      .CODE
        PUBLIC _mixed
_mixed PROC
         push  bp
         mov   bp,sp
; access and change _value
         mov   ax, seg _DATA
         mov   ds,ax
         mov   ax,SEG _value
         mov   es,ax
         mov   es:_value,10h
; return the passed variable
         mov   ax,[bp+6]
         pop   bp
         ret
_mixed   ENDP
         END

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