Hi all,
Okay, this is the issue. I've isolated it way down to some very basic
functionality, and made a reasonable test bed. I'll post the code below.
When MYINLINE = 1, then the program executes correctly. When MYINLINE is 0,
then it stops with a single step exception. I was stepping through the code and
from my understanding there is something definitely wrong when a function call
is made instead of the inline code. Bare in mind, my understaind could be what
is wrong :)
>From my understand this is what happens.
pushf - pushes the eflags onto the stack, decrements esp
mymemcpy - simple memcpy
popf - pops the eflags from the stack into the eflgs register, increments esp
This is basically the program below. When the inlining is not used, for some
reason, the stack gets corrupted. When the variables to be passed into memcpy
are done, they overwrite the location where the eflags register was stored (from
the pushf). This then causes some things to mess up. When inlining is used.
this nicely does not happen.
I always hesitate to say bug as its probably something i'm not specifying or
some misunderstanding.
Any ideas?
Yamin
*****************************************************
main.cpp
*****************************************************
#include <io.h>
#include <stdio.h>
#if 0
#include "chead.h"
#else
#define KS_DISABLE() \
__asm__ __volatile__ ( \
"pushfl;" \
: \
: \
: "memory", "%esp");
#define KS_ENABLE() \
__asm__ __volatile__ ( \
"popfl;" \
: \
: \
: "memory", "%esp");
char * mymemcpy(void *dv, void *sv, int num)
{
char * d = (char*)dv;
char * s = (char*)sv;
int i;
for( i = 0; i < num; i++) *d++ = *s++;
}
#endif
#define MYINLINE 1
int main()
{
#if MYINLINE
char *d;
char *s;
int i;
#endif
char mysrc[] = "HELLO YAMIN\r\n";
char mydst[32];
printf ("starting popf test\r\n");
KS_DISABLE();
#if MYINLINE
d = (char*) mydst;
s = (char*) mysrc;
for( i = 0; i < sizeof(mysrc); i++) *d++ = *s++;
#else
mymemcpy( mydst, mysrc, sizeof(mysrc) );
#endif
KS_ENABLE();
printf ("ending popf test: %s\r\n", mydst);
}
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