Thread: How to link and compile a .c and .asm file?

Hello,

I have the following files:

mainlinemem.c...

Code:

#include <stdio.h>

int gcdmem(int a,int b);

int main()
{
    int result;
    int a;
    int b;

    a = 46;
    b = 90;
    printf("%d and %d have a gcd of %d\n",a,b,gcdmem(a,b));

    a = 9863;
    b = 41272;
    printf("%d and %d have a gcd of %d\n",a,b,gcdmem(a,b));
}

and:

gcdmem.asm...

Code:

segment .data

segment .bss
x:    resd  1
y:    resd  1
segment .text
    global gcdmem
gcdmem:
    push ebp
    mov  ebp,esp
    mov  eax,[ebp+8]        ; x
    mov  [x],eax
    mov  eax,[ebp+12]       ; y
    mov  [y],eax
looptop:
    mov  eax,[x]
    cmp  eax,0              ; if (x == 0) we're done
    je   goback
    mov  ebx,[y]
    cmp  eax,ebx            ; make certain x is the larger number
    jge  modulo
    mov  [x],ebx
    mov  [y],eax
modulo:
    mov  ebx,[y]
    mov  eax,[x]
    cdq                    ; set up for division
    idiv ebx               ; divide edxeax by ebx
    mov  [x],edx           ; the remainder is in edx
    jmp  looptop

goback:
    mov  eax,[y]           ; return y
    mov  esp,ebp
    pop  ebp
    ret

Can anyone show me how to compile these files so I can run it?

I am on Windows XP and have mingw installed, and also NASM and alink.exe.

I've used google to find the answer, but every solution I tried was unsuccessful.

Use GCC, it makes C/ASM integration incredibly easy:

Code:

gcc mainlinemem.c gcdmem.c

You could obviously add more command-line options, but that's really all it takes.

I did this a while back (did not target XP though), you need to specify the object filetype to nasm and compile the C file to an object file (-c for gcc), then you can link them.

Code:

nasm -f <object fileformat> -o gcdmem.o gcdmem.asm
gcc -c mainlinemem.c
gcc mainlinemem.o gcdmem.o

You may need to add an entry point argument to nasm as well.

I am on Windows XP and have mingw installed, and also NASM and alink.exe.

You should pretty much always use the compiler to do linking.

Here it doesn't matter so much because both files are simple and only C and assembler are involved.

If you add C++, for example, at a later date things can extremely messy trying to use the linker directly.

Soma

Originally Posted by Subsonics

I did this a while back (did not target XP though), you need to specify the object filetype to nasm and compile the C file to an object file (-c for gcc), then you can link them.

Code:

nasm -f <object fileformat> -o gcdmem.o gcdmem.asm
gcc -c mainlinemem.c
gcc mainlinemem.o gcdmem.o

You may need to add an entry point argument to nasm as well.

Thank you, it works now.