45 lines
962 B
C
45 lines
962 B
C
/* NOCW */
|
|
/* dggccbug.c */
|
|
/* bug found by Eric Young (eay@cryptsoft.com) - May 1995 */
|
|
|
|
#include <stdio.h>
|
|
|
|
/*
|
|
* There is a bug in gcc version 2.5.8 (88open OCS/BCS, DG-2.5.8.3, Oct 14
|
|
* 1994) as shipped with DGUX 5.4R3.10 that can be bypassed by defining
|
|
* DG_GCC_BUG in my code. The bug manifests itself by the vaule of a pointer
|
|
* that is used only by reference, not having it's value change when it is
|
|
* used to check for exiting the loop. Probably caused by there being 2
|
|
* copies of the valiable, one in a register and one being an address that is
|
|
* passed.
|
|
*/
|
|
|
|
/*-
|
|
* compare the out put from
|
|
* gcc dggccbug.c; ./a.out
|
|
* and
|
|
* gcc -O dggccbug.c; ./a.out
|
|
* compile with -DFIXBUG to remove the bug when optimising.
|
|
*/
|
|
|
|
void inc(a)
|
|
int *a;
|
|
{
|
|
(*a)++;
|
|
}
|
|
|
|
main()
|
|
{
|
|
int p = 0;
|
|
#ifdef FIXBUG
|
|
int dummy;
|
|
#endif
|
|
|
|
while (p < 3) {
|
|
fprintf(stderr, "%08X\n", p);
|
|
inc(&p);
|
|
#ifdef FIXBUG
|
|
dummy += p;
|
|
#endif
|
|
}
|
|
}
|