70 lines
1.3 KiB
C
70 lines
1.3 KiB
C
/* origin: FreeBSD /usr/src/lib/msun/src/s_sin.c */
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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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void sincos(double x, double *sin, double *cos)
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{
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double y[2], s, c;
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uint32_t ix;
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unsigned n;
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GET_HIGH_WORD(ix, x);
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ix &= 0x7fffffff;
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/* |x| ~< pi/4 */
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if (ix <= 0x3fe921fb) {
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/* if |x| < 2**-27 * sqrt(2) */
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if (ix < 0x3e46a09e) {
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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 = 1.0;
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return;
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}
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*sin = __sin(x, 0.0, 0);
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*cos = __cos(x, 0.0);
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return;
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}
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/* sincos(Inf or NaN) is NaN */
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if (ix >= 0x7ff00000) {
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*sin = *cos = x - x;
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return;
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}
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/* argument reduction needed */
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n = __rem_pio2(x, y);
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s = __sin(y[0], y[1], 1);
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c = __cos(y[0], y[1]);
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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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