Hello, All !
I found a significant BUG when using struct assignment.
Here is the sample:
struct x{
int a,b,c,d;
};
struct x *v[2];
void swap(void)
{
struct x tmp;
tmp=*v[0];
*v[0]=*v[1];
*v[1]=tmp;
}
And here is GCC's listing (with -O option):
/***********************
* Function `swap'
***********************/
swap:
/* prologue: frame size = 8 */
.L__FrameSize_swap=0x8
.L__FrameOffset_swap=0x8
sub #8, r1 ; 8, fpn 0
/* prologue end (size=1) */
mov &v, r15
mov @r15+, @r1
mov @r15+, 2(r1)
mov @r15+, 4(r1)
mov @r15+, 6(r1)
mov &v+2, r14
mov @r14+, 0(r15)
mov @r14+, 2(r15)
mov @r14+, 4(r15)
mov @r14+, 6(r15)
mov &v+2, r15
mov @r1+, 0(r15) ;We should not change the stack pointer here !
mov @r1+, 2(r15)
mov @r1+, 4(r15)
mov @r1+, 6(r15)
/* epilogue: frame size=8 */
add #8, r1 ;After this command the stack pointer points to
the illegal location !
ret
/* epilogue end (size=2) */
/* function swap size 33 (30) */
I use win32 version (from 10.12.2002).
Thanks, Oleg.
