On Mon, Aug 29, 2005 at 07:28:07PM +0100, Jonathon McKitrick wrote:
> On Sun, Aug 28, 2005 at 09:45:26PM -0700, Matthew Dillon wrote:
> :
> : :
> : :Is there a trick to calling malloc from NASM code? It links fine and steps
> : :into malloc() fine, but returns a NULL pointer.
> :
> : Nope, should work just fine. The assembly should look something like
> : this (assuming we are talking about a userland program here):
> :
> : pushl $bytes_to_malloc
> : call malloc
> : addl $4,%esp
> : [ returns pointer in %eax ]
>
> That's exactly what I thought. And it works fine with gas. But under NASM, I
> get a NULL pointer returned. It steps into malloc, but doesn't return a mem
> pointer.
err() should tell you what was wrong(and terminates the program):
section .text
extern err
extern malloc
:
push dword 0x80000000
call malloc
add esp, 4
test eax, eax
jnz .ok
.oops:
;; err(1, "malloc")
push .oops_msg
push dword 1
call err
; UNREACHED
.oops_msg:
db "malloc", 0
.ok:
