118 lines
2.5 KiB
C
118 lines
2.5 KiB
C
/* origin: FreeBSD /usr/src/lib/msun/src/s_sinf.c */
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/*
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* Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
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* Optimized by Bruce D. Evans.
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*/
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/*
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* ====================================================
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* Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
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*
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* Developed at SunPro, a Sun Microsystems, Inc. business.
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* Permission to use, copy, modify, and distribute this
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* software is freely granted, provided that this notice
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* is preserved.
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* ====================================================
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*/
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#define _GNU_SOURCE
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#include "libc/math/libm.h"
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/* Small multiples of pi/2 rounded to double precision. */
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static const double
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s1pio2 = 1*M_PI_2, /* 0x3FF921FB, 0x54442D18 */
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s2pio2 = 2*M_PI_2, /* 0x400921FB, 0x54442D18 */
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s3pio2 = 3*M_PI_2, /* 0x4012D97C, 0x7F3321D2 */
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s4pio2 = 4*M_PI_2; /* 0x401921FB, 0x54442D18 */
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void sincosf(float x, float *sin, float *cos)
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{
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double y;
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float_t s, c;
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uint32_t ix;
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unsigned n, sign;
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GET_FLOAT_WORD(ix, x);
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sign = ix >> 31;
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ix &= 0x7fffffff;
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/* |x| ~<= pi/4 */
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if (ix <= 0x3f490fda) {
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/* |x| < 2**-12 */
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if (ix < 0x39800000) {
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/* raise inexact if x!=0 and underflow if subnormal */
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FORCE_EVAL(ix < 0x00100000 ? x/0x1p120f : x+0x1p120f);
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*sin = x;
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*cos = 1.0f;
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return;
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}
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*sin = __sindf(x);
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*cos = __cosdf(x);
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return;
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}
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/* |x| ~<= 5*pi/4 */
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if (ix <= 0x407b53d1) {
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if (ix <= 0x4016cbe3) { /* |x| ~<= 3pi/4 */
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if (sign) {
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*sin = -__cosdf(x + s1pio2);
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*cos = __sindf(x + s1pio2);
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} else {
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*sin = __cosdf(s1pio2 - x);
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*cos = __sindf(s1pio2 - x);
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}
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return;
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}
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/* -sin(x+c) is not correct if x+c could be 0: -0 vs +0 */
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*sin = -__sindf(sign ? x + s2pio2 : x - s2pio2);
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*cos = -__cosdf(sign ? x + s2pio2 : x - s2pio2);
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return;
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}
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/* |x| ~<= 9*pi/4 */
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if (ix <= 0x40e231d5) {
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if (ix <= 0x40afeddf) { /* |x| ~<= 7*pi/4 */
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if (sign) {
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*sin = __cosdf(x + s3pio2);
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*cos = -__sindf(x + s3pio2);
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} else {
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*sin = -__cosdf(x - s3pio2);
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*cos = __sindf(x - s3pio2);
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}
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return;
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}
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*sin = __sindf(sign ? x + s4pio2 : x - s4pio2);
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*cos = __cosdf(sign ? x + s4pio2 : x - s4pio2);
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return;
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}
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/* sin(Inf or NaN) is NaN */
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if (ix >= 0x7f800000) {
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*sin = *cos = x - x;
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return;
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}
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/* general argument reduction needed */
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n = __rem_pio2f(x, &y);
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s = __sindf(y);
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c = __cosdf(y);
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switch (n&3) {
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case 0:
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*sin = s;
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*cos = c;
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break;
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case 1:
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*sin = c;
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*cos = -s;
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break;
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case 2:
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*sin = -s;
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*cos = -c;
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break;
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case 3:
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default:
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*sin = -c;
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*cos = s;
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break;
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}
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}
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