Attachment 312981 Details for Bug 43354 – Speed measurement program for the testcase

Speed measurement program for the testcase

test_speed.c (text/x-csrc), 6.31 KB, created by Denys Vlasenko on 2008-07-30 10:40:57 UTC

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Creator: Denys Vlasenko

Created: 2008-07-30 10:40:57 UTC

Size: 6.31 KB

patch

obsolete

>/* Bug 43354: expm1l(x) overflows when 11356.1768 < x <= 11356.5234 */
>/* This testcase shows that approximating expm1l(x) with expl(x)
> * for x >= 128.0 makes expm1l(x) work correctly for x up to
> * 11356.5234062941435695 and even provides more precise results */
>
>/* s_expm1l.S is from glibc 2.7, s_expm1l_fixed.S is a new algorithm */
>
>/* gcc -Os -lm test_speed.c s_expm1l.S s_expm1l_fixed.S */
>
>#include <stdlib.h> /* for atof */
>#include <stdint.h>
>#include <stdio.h>
>#include <math.h>
>#include <sys/time.h>
>
>long double __glibc27_expm1l_fixed(long double x);
>long double __glibc27_expm1l(long double x);
>
>static void hack_print(long double *v)
>{
>	printf("Value: %.20Le  ", *v);
>	printf("Bit value: %04x %04x %04x %04x %04x\n",
>		((uint16_t*)v)[4],
>		((uint16_t*)v)[3],
>		((uint16_t*)v)[2],
>		((uint16_t*)v)[1],
>		((uint16_t*)v)[0]
>	);
>}
>
>static int hack_inc(long double *v)
>{
>	uint32_t *lowbits = (uint32_t *)v;
>	if (*lowbits != 0xffffffff) {
>		if (!(*lowbits & 0xfffff)) {
>			printf("%.20Le", v);
>			printf(" (0x%08x)\r", (unsigned)(*lowbits));
>			fflush(NULL);
>		}
>		(*lowbits)++;
>		return 1;
>	}
>	return 0;
>}
>
>int main(int argc, char **argv)
>{
>	long double v;
>	long double e;
>	long double e1org;
>	long double e1fix;
>	int count, i;
>	unsigned tv_usec, tv_usec_stop;
>	struct timeval tv;
>
>	v = atof(argv[1]);
>	hack_print(&v);
>
>	e = expl(v);
>	e1org = __glibc27_expm1l(v);
>	e1fix = __glibc27_expm1l_fixed(v);
>	printf("Testing at:\n");
>	printf("%.20Le: %.20Le %.20Le (%.20Le)\n", v, e1org, e1fix, e);
>
>#define REP 9
>
>	printf("Current algorithm, iterations in 0.1 sec:");
>for (i = 0; i < REP; i++) {
>	gettimeofday(&tv, NULL);
>	tv_usec_stop = tv.tv_sec * (1000*1000) + tv.tv_usec + 100*1000;
>	count = 0;
>	do {
>		/* 64 calls */
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v); e1org = __glibc27_expm1l(v);
>		count++;
>		gettimeofday(&tv, NULL);
>		tv_usec = tv.tv_sec * (1000*1000) + tv.tv_usec;
>	} while (tv_usec < tv_usec_stop);
>	printf(" %6d", count); fflush(NULL);
>}
>printf("\n");
>
>	printf("    New algorithm, iterations in 0.1 sec:");
>for (i = 0; i < REP; i++) {
>	gettimeofday(&tv, NULL);
>	tv_usec_stop = tv.tv_sec * (1000*1000) + tv.tv_usec + 100*1000;
>	count = 0;
>	do {
>		/* 64 calls */
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v); e1org = __glibc27_expm1l_fixed(v);
>		count++;
>		gettimeofday(&tv, NULL);
>		tv_usec = tv.tv_sec * (1000*1000) + tv.tv_usec;
>	} while (tv_usec < tv_usec_stop);
>	printf(" %6d", count); fflush(NULL);
>}
>printf("\n");
>
>	return 0;
>}

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Attachments on bug 43354: 312979 | 312981