Andrew Haley wrote:
That is strange. A bit of debugging would be required to understand
why that happens.
#include <stdio.h>
#include <math.h>
double length = 0.00106722283403500495;
double angle = 0.60066412215710574;
void dump(double d)
{
unsigned char *c = (unsigned char *)&d;
int i;
for (i = 0; i < 8; i++, c++) printf("%2.2x", *c);
printf("\n");
}
void calc(void)
{
double sincos1, sincos2;
asm volatile("fldl %2\n"
"fsincos\n"
"fstpl %0\n"
"fstpl %1"
: "=m" (sincos1), "=m" (sincos2) : "m" (angle));
dump(sincos1);
dump(cos(angle));
}
int main()
{
calc();
return 0;
}
I compile the above with gcc 4.1.2 (redhat) or 4.3.2 (debian)
(it gives the same result).
On an AMD (opteron as it seems):
/users/cro> ./a.out
75d882701366ea3f
75d882701366ea3f
On an intel (so do I think):
/users/cro> ./a.out
76d882701366ea3f
75d882701366ea3f
The least significant bit differs.
If that may help...
Cédric
