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efficient sincos based on sin and cos

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This commit is contained in:
nsz 2012-03-15 08:17:28 +01:00
parent 32ca5ef3ff
commit 0144b45b71
5 changed files with 251 additions and 8 deletions
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4
include/math.h
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@ -382,6 +382,10 @@ long double ynl(int, long double);
double scalb(double, double);
float scalbf(float, float);
long double scalbl(long double, long double);
void sincos(double, double*, double*);
void sincosf(float, float*, float*);
void sincosl(long double, long double*, long double*);
#endif
#ifdef __cplusplus

8
src/linux/sincos.c
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@ -1,8 +0,0 @@
#define _GNU_SOURCE
#include <math.h>
void sincos(double t, double *y, double *x)
{
*y = sin(t);
*x = cos(t);
}

68
src/math/sincos.c Normal file
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@ -0,0 +1,68 @@
/* origin: FreeBSD /usr/src/lib/msun/src/s_sin.c */
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "libm.h"
void sincos(double x, double *sin, double *cos)
{
double y[2], s, c;
uint32_t n, ix;
GET_HIGH_WORD(ix, x);
ix &= 0x7fffffff;
/* |x| ~< pi/4 */
if (ix <= 0x3fe921fb) {
/* if |x| < 2**-27 * sqrt(2) */
if (ix < 0x3e46a09e) {
/* raise inexact if x != 0 */
if ((int)x == 0) {
*sin = x;
*cos = 1.0;
}
return;
}
*sin = __sin(x, 0.0, 0);
*cos = __cos(x, 0.0);
return;
}
/* sincos(Inf or NaN) is NaN */
if (ix >= 0x7ff00000) {
*sin = *cos = x - x;
return;
}
/* argument reduction needed */
n = __rem_pio2(x, y);
s = __sin(y[0], y[1], 1);
c = __cos(y[0], y[1]);
switch (n&3) {
case 0:
*sin = s;
*cos = c;
break;
case 1:
*sin = c;
*cos = -s;
break;
case 2:
*sin = -s;
*cos = -c;
break;
case 3:
default:
*sin = -c;
*cos = s;
break;
}
}

113
src/math/sincosf.c Normal file
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@ -0,0 +1,113 @@
/* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */
/*
* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
* Optimized by Bruce D. Evans.
*/
/*
* ====================================================
* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
*
* Developed at SunPro, a Sun Microsystems, Inc. business.
* Permission to use, copy, modify, and distribute this
* software is freely granted, provided that this notice
* is preserved.
* ====================================================
*/
#include "libm.h"
/* Small multiples of pi/2 rounded to double precision. */
static const double
s1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
s2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
s3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
void sincosf(float x, float *sin, float *cos)
{
double y, s, c;
uint32_t n, hx, ix;
GET_FLOAT_WORD(hx, x);
ix = hx & 0x7fffffff;
/* |x| ~<= pi/4 */
if (ix <= 0x3f490fda) {
/* |x| < 2**-12 */
if (ix < 0x39800000) {
/* raise inexact if x != 0 */
if((int)x == 0) {
*sin = x;
*cos = 1.0f;
}
return;
}
*sin = __sindf(x);
*cos = __cosdf(x);
return;
}
/* |x| ~<= 5*pi/4 */
if (ix <= 0x407b53d1) {
if (ix <= 0x4016cbe3) { /* |x| ~<= 3pi/4 */
if (hx < 0x80000000) {
*sin = __cosdf(x - s1pio2);
*cos = __sindf(s1pio2 - x);
} else {
*sin = -__cosdf(x + s1pio2);
*cos = __sindf(x + s1pio2);
}
return;
}
*sin = __sindf(hx < 0x80000000 ? s2pio2 - x : -s2pio2 - x);
*cos = -__cosdf(hx < 0x80000000 ? x - s2pio2 : x + s2pio2);
return;
}
/* |x| ~<= 9*pi/4 */
if (ix <= 0x40e231d5) {
if (ix <= 0x40afeddf) { /* |x| ~<= 7*pi/4 */
if (hx < 0x80000000) {
*sin = -__cosdf(x - s3pio2);
*cos = __sindf(x - s3pio2);
} else {
*sin = __cosdf(x + s3pio2);
*cos = __sindf(-s3pio2 - x);
}
return;
}
*sin = __sindf(hx < 0x80000000 ? x - s4pio2 : x + s4pio2);
*cos = __cosdf(hx < 0x80000000 ? x - s4pio2 : x + s4pio2);
return;
}
/* sin(Inf or NaN) is NaN */
if (ix >= 0x7f800000) {
*sin = *cos = x - x;
return;
}
/* general argument reduction needed */
n = __rem_pio2f(x, &y);
s = __sindf(y);
c = __cosdf(y);
switch (n&3) {
case 0:
*sin = s;
*cos = c;
break;
case 1:
*sin = c;
*cos = -s;
break;
case 2:
*sin = -s;
*cos = -c;
break;
case 3:
default:
*sin = -c;
*cos = s;
break;
}
}

66
src/math/sincosl.c Normal file
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@ -0,0 +1,66 @@
#include "libm.h"
#if LDBL_MANT_DIG == 53 && LDBL_MAX_EXP == 1024
void sincosl(long double x, long double *sin, long double *cos)
{
double s, c;
sincos(x, &s, &c);
*sin = s;
*cos = c;
}
#elif (LDBL_MANT_DIG == 64 || LDBL_MANT_DIG == 113) && LDBL_MAX_EXP == 16384
#include "__rem_pio2l.h"
void sincosl(long double x, long double *sin, long double *cos)
{
union IEEEl2bits u;
int n;
long double y[2], s, c;
u.e = x;
u.bits.sign = 0;
/* x = +-0 or subnormal */
if (!u.bits.exp) {
*sin = x;
*cos = 1.0;
return;
}
/* x = nan or inf */
if (u.bits.exp == 0x7fff) {
*sin = *cos = x - x;
return;
}
/* |x| < pi/4 */
if (u.e < M_PI_4) {
*sin = __sinl(x, 0, 0);
*cos = __cosl(x, 0);
return;
}
n = __rem_pio2l(x, y);
s = __sinl(y[0], y[1], 1);
c = __cosl(y[0], y[1]);
switch (n & 3) {
case 0:
*sin = s;
*cos = c;
break;
case 1:
*sin = c;
*cos = -s;
break;
case 2:
*sin = -s;
*cos = -c;
break;
case 3:
default:
*sin = -c;
*cos = s;
break;
}
}
#endif