Version française
Home     About     Download     Resources     Contact us    

This site is updated infrequently. For up-to-date information, please visit the new OCaml website at

Browse thread
Interface between Ocaml and Assembler
[ Home ] [ Index: by date | by threads ]
[ Search: ]

[ Message by date: previous | next ] [ Message in thread: previous | next ] [ Thread: previous | next ]
Date: 2008-01-04 (16:40)
From: David LONY <david.lony@p...>
Subject: Re: [Caml-list] Interface between Ocaml and Assembler
Ok ok..

But it will be easier to make a "bridge" like this one : "asm code" -> 
"C code"->"Ocaml code" ?
For instance I made 3 program :
The first one in assembly (gas.S):

.global _start

        call main

The second in C (test.c):

#include <stdio.h>
#include <caml/mlvalues.h>
#include <caml/callback.h>

int test_char(int n)
  static value * test_char_closure = NULL;
  if (test_char_closure == NULL)
        test_char_closure = caml_named_value("caml_test_char");
  return Int_val(caml_callback(*test_char_closure, Val_int(n)));

int main(int argc, char ** argv)
  int result;
  result = test_char(10);
  printf("%d\n", result);
  return 0;

and the last in Ocaml ( :

let test_char a = a+1
let _ = Callback.register "caml_test_char" test_char;;

But when I try to compile and link all object it fails...
as gas.S -o gas.o
gcc -c test.c -o test.o
ocamlopt -output-obj -o truc_main.o
ld -o test gas.o test.o truc_main.o -L/usr/lib/ocaml/3.09.2/ -lasmrun 
-lm -ldl

/usr/lib/ocaml/3.09.2//libasmrun.a(ints.o): In function 
(.text+0xb4b): undefined reference to `__udivdi3'
/usr/lib/ocaml/3.09.2//libasmrun.a(ints.o): In function `caml_int64_mod':
(.text+0xe55): undefined reference to `__moddi3'
/usr/lib/ocaml/3.09.2//libasmrun.a(ints.o): In function `caml_int64_div':
(.text+0xe9e): undefined reference to `__divdi3'

Does anyone has a solution ?

David LONY

Alain Frisch a écrit :
> David LONY wrote:
>> Is it possible to interface assembler code with an Ocaml code ? I 
>> it possible to call a Ocaml function from an assembler code 
>> by using the asm instruction "call my_function" (gas asm)?
> Yes, you can call an OCaml function from assembler using the same 
> method as from C, that is through caml_callback* functions (see 
> Section 18.7.1 in the OCaml manual). However, dealing with the GC 
> properly in assembler is tricky: you'll have to reproduce the behavior 
> of the CAMLlocal and CAMLparam macros.
> -- Alain