To: djgpp AT delorie DOT com
Subject: Problems with extended asm...
Message-ID: <19961231.085638.4879.0.chambersb@juno.com>
From: chambersb AT juno DOT com (Benjamin D Chambers)
Date: Mon, 30 Dec 1996 11:51:47 EST

Sorry if this is an obvious mistake, but I misplaced my copy of Brennan's
Guide to ASM, and I won't have www access for a while...

Anyways, I'm trying to write some values to a buffer in memory. 
Eventually, I'll get around to writing real values, but for now I'm just
writing a constant.  This is the code I have:

--file test.c--
#include <malloc.h>
#include <stdio.h>

unsigned char *data;
int size;

int main(void)
{
  size=20;
  data=(unsigned char *)malloc(size);
  size=16;
  asm("0:                                       \n
        movb    $1,             (%%eax)         \n
        incl    %%eax                           \n
        decl    %%edx                           \n
        cmp     $0,             %%edx           \n
        jne     0                               \n
       "
  :     // No Output
  : "d" (size),
    "a" (data)
  : "memory", "%cc"
  );
  for (size=0;size<16;size++)
   printf("At line %d: %d\n",size,data[size]);
  return(0);
}

Now, when I run this program, I would expect it to print all 1's - but
only the first line is.  The rest is random garbage.

My question is: What am I doing wrong?

Thanx in advance,

...Chambers