/* $NetBSD: tune.c,v 1.1.1.2 2014/04/24 12:45:39 pettai Exp $ */ /* Tune the Karatsuba parameters * * Tom St Denis, tomstdenis@gmail.com */ #include #include /* 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 #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; } /* Source: /cvs/libtom/libtommath/etc/tune.c,v */ /* Revision: 1.3 */ /* Date: 2006/03/31 14:18:47 */