Assembly code (written for masm) in C program (compiled with gcc)… how?

Question

I have assembly code and I want to implement it into a C program. I've been using masm to get my assembly code working, and I'm using gcc to compile C code.

I'm using NetBeans in Windows XP.

I want the command prompt to go fullscreen, then draw a line, like this does:

.model small
.stack

.code
    main proc far
    mov ax,@data
    mov DS,ax
    mov ah,00h
    mov al,12h
    int 10h 
    mov ah,02h
    mov dh,14 
    mov dl,37
    int 10h

    mov di,65
    mov ah,0ch
    mov bh,00h
    mov al,09h
    mov Cx,290
    mov dx,200

arriba: int 10h
    inc cx      
    dec di      
    Jnz arriba
    mov di,65
    mov ah,08h
    int 21h
    mov ax,4c00h
    int 21h 

    main endp
    end main

That code works if I use masm, but I don't know how to get it working inside my C program... thanks in advance!

Answer 1

You can't mix DOS interrupts with the Windows API. You probably need to use DirectX's full screen mode instead.

Answer 2

Generally mixing assembler with C can be done with GCC by defining functions written in asm in separate assembler file, which if compiled to .o and then linked together with C program, which calls the function that was in object compiled from assembler.

For that you need to know calling convention, how parameters are passed in stack or registers and write header which defines function prototype, which is implemented in assembler.

Some examples how to mix asm with C:

http://www.cs.lmu.edu/~ray/notes/nasmexamples/

Other way would be to use GCC inline assembler syntax: http://www.ibiblio.org/gferg/ldp/GCC-Inline-Assembly-HOWTO.html

Note that originally GNU Assembler syntax is quite different than masm and many other x86 assemblers. However looks like this has been fixed in v. 2.10 (http://en.wikipedia.org/wiki/GNU_Assembler)

Also @Neil's answer stands, you cannot do DOS Interrupts from windows program.