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path: root/src/math/sincos.c
blob: 442e285e3161cd8c7d6f2d683b2894c0ebf9f1e2 (plain) (blame)
 ```1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 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; } } ``````