147 lines
3.1 KiB
C
147 lines
3.1 KiB
C
/* Tune the Karatsuba parameters
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*
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* Tom St Denis, tstdenis82@gmail.com
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*/
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#include <tommath.h>
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#include <stdint.h>
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/* how many times todo each size mult. Depends on your computer. For slow computers
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* this can be low like 5 or 10. For fast [re: Athlon] should be 25 - 50 or so
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*/
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#define TIMES (1UL<<14UL)
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#ifndef X86_TIMER
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/* RDTSC from Scott Duplichan */
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static uint64_t TIMFUNC(void)
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{
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# if defined __GNUC__
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# if defined(__i386__) || defined(__x86_64__)
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/* version from http://www.mcs.anl.gov/~kazutomo/rdtsc.html
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* the old code always got a warning issued by gcc, clang did not complain...
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*/
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unsigned hi, lo;
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__asm__ __volatile__("rdtsc" : "=a"(lo), "=d"(hi));
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return ((uint64_t)lo)|(((uint64_t)hi)<<32);
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# else /* gcc-IA64 version */
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unsigned long result;
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__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
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while (__builtin_expect((int) result == -1, 0))
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__asm__ __volatile__("mov %0=ar.itc" : "=r"(result) :: "memory");
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return result;
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# endif
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/* Microsoft and Intel Windows compilers */
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# elif defined _M_IX86
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__asm rdtsc
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# elif defined _M_AMD64
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return __rdtsc();
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# elif defined _M_IA64
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# if defined __INTEL_COMPILER
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# include <ia64intrin.h>
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# endif
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return __getReg(3116);
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# else
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# error need rdtsc function for this build
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# endif
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}
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/* *INDENT-OFF* */
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/* generic ISO C timer */
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static uint64_t LBL_T;
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static void t_start(void) { LBL_T = TIMFUNC(); }
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static uint64_t t_read(void) { return TIMFUNC() - LBL_T; }
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/* *INDENT-ON* */
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#else
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extern void t_start(void);
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extern uint64_t t_read(void);
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#endif
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static uint64_t time_mult(int size, int s)
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{
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unsigned long x;
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mp_int a, b, c;
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uint64_t t1;
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mp_init(&a);
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mp_init(&b);
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mp_init(&c);
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mp_rand(&a, size);
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mp_rand(&b, size);
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if (s == 1) {
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KARATSUBA_MUL_CUTOFF = size;
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} else {
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KARATSUBA_MUL_CUTOFF = 100000;
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}
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t_start();
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for (x = 0; x < TIMES; x++) {
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mp_mul(&a,&b,&c);
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}
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t1 = t_read();
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mp_clear(&a);
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mp_clear(&b);
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mp_clear(&c);
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return t1;
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}
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static uint64_t time_sqr(int size, int s)
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{
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unsigned long x;
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mp_int a, b;
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uint64_t t1;
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mp_init(&a);
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mp_init(&b);
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mp_rand(&a, size);
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if (s == 1) {
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KARATSUBA_SQR_CUTOFF = size;
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} else {
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KARATSUBA_SQR_CUTOFF = 100000;
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}
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t_start();
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for (x = 0; x < TIMES; x++) {
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mp_sqr(&a,&b);
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}
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t1 = t_read();
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mp_clear(&a);
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mp_clear(&b);
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return t1;
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}
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int main(void)
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{
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uint64_t t1, t2;
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int x, y;
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for (x = 8; ; x += 2) {
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t1 = time_mult(x, 0);
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t2 = time_mult(x, 1);
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printf("%d: %9llu %9llu, %9llu\n", x, t1, t2, t2 - t1);
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if (t2 < t1) break;
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}
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y = x;
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for (x = 8; ; x += 2) {
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t1 = time_sqr(x, 0);
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t2 = time_sqr(x, 1);
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printf("%d: %9llu %9llu, %9llu\n", x, t1, t2, t2 - t1);
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if (t2 < t1) break;
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}
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printf("KARATSUBA_MUL_CUTOFF = %d\n", y);
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printf("KARATSUBA_SQR_CUTOFF = %d\n", x);
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return 0;
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}
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/* ref: $Format:%D$ */
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/* git commit: $Format:%H$ */
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/* commit time: $Format:%ai$ */
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