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/* Tune the Karatsuba parameters
*
* Tom St Denis, tomstdenis@iahu.ca
*/
#include <tommath.h>
#include <time.h>
/* how many times todo each size mult. Depends on your computer. For slow computers
* this can be low like 5 or 10. For fast [re: Athlon] should be 25 - 50 or so
*/
#define TIMES (1UL<<14UL)
/* RDTSC from Scott Duplichan */
static ulong64 TIMFUNC (void)
{
#if defined __GNUC__
#if defined(__i386__) || defined(__x86_64__)
unsigned long long a;
__asm__ __volatile__ ("rdtsc\nmovl %%eax,%0\nmovl %%edx,4+%0\n"::"m"(a):"%eax","%edx");
return a;
#else /* gcc-IA64 version */
unsigned long result;
__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
while (__builtin_expect ((int) result == -1, 0))
__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
return result;
#endif
// Microsoft and Intel Windows compilers
#elif defined _M_IX86
__asm rdtsc
#elif defined _M_AMD64
return __rdtsc ();
#elif defined _M_IA64
#if defined __INTEL_COMPILER
#include <ia64intrin.h>
#endif
return __getReg (3116);
#else
#error need rdtsc function for this build
#endif
}
#ifndef X86_TIMER
/* generic ISO C timer */
ulong64 LBL_T;
void t_start(void) { LBL_T = TIMFUNC(); }
ulong64 t_read(void) { return TIMFUNC() - LBL_T; }
#else
extern void t_start(void);
extern ulong64 t_read(void);
#endif
ulong64 time_mult(int size, int s)
{
unsigned long x;
mp_int a, b, c;
ulong64 t1;
mp_init (&a);
mp_init (&b);
mp_init (&c);
mp_rand (&a, size);
mp_rand (&b, size);
if (s == 1) {
KARATSUBA_MUL_CUTOFF = size;
} else {
KARATSUBA_MUL_CUTOFF = 100000;
}
t_start();
for (x = 0; x < TIMES; x++) {
mp_mul(&a,&b,&c);
}
t1 = t_read();
mp_clear (&a);
mp_clear (&b);
mp_clear (&c);
return t1;
}
ulong64 time_sqr(int size, int s)
{
unsigned long x;
mp_int a, b;
ulong64 t1;
mp_init (&a);
mp_init (&b);
mp_rand (&a, size);
if (s == 1) {
KARATSUBA_SQR_CUTOFF = size;
} else {
KARATSUBA_SQR_CUTOFF = 100000;
}
t_start();
for (x = 0; x < TIMES; x++) {
mp_sqr(&a,&b);
}
t1 = t_read();
mp_clear (&a);
mp_clear (&b);
return t1;
}
int
main (void)
{
ulong64 t1, t2;
int x, y;
for (x = 8; ; x += 2) {
t1 = time_mult(x, 0);
t2 = time_mult(x, 1);
printf("%d: %9llu %9llu, %9llu\n", x, t1, t2, t2 - t1);
if (t2 < t1) break;
}
y = x;
for (x = 8; ; x += 2) {
t1 = time_sqr(x, 0);
t2 = time_sqr(x, 1);
printf("%d: %9llu %9llu, %9llu\n", x, t1, t2, t2 - t1);
if (t2 < t1) break;
}
printf("KARATSUBA_MUL_CUTOFF = %d\n", y);
printf("KARATSUBA_SQR_CUTOFF = %d\n", x);
return 0;
}
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