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87 lines
2.1 KiB
C
87 lines
2.1 KiB
C
module std::math::nolibc @if(env::NO_LIBC);
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fn float _cosf(float x) @extern("cosf") @weak @nostrip
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{
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uint ix = bitcast(x, uint);
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uint sign = ix >> 31;
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ix &= 0x7fffffff;
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switch
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{
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case (ix <= 0x3f490fda):
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// |x| < 2**-12
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if (ix < 0x39800000)
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{
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/* raise inexact if x != 0 */
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force_eval_add(x, 0x1p120f);
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return 1.0f;
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}
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return __cosdf(x);
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// |x| ~<= 5*pi/4
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case (ix <= 0x407b53d1):
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// |x| ~> 3*pi/4
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if (ix > 0x4016cbe3) return -__cosdf(sign ? x + S2PI2 : x - S2PI2);
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return sign ? __sindf(x + S1PI2) : __sindf(S1PI2 - x);
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// |x| ~<= 9*pi/4
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case (ix <= 0x40e231d5):
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if (ix > 0x40afeddf) return __cosdf(sign ? x + S4PI2 : x - S4PI2);
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return sign ? __sindf((double)(-x) - S3PI2) : __sindf(x - S3PI2);
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}
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// general argument reduction needed
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double y @noinit;
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switch (__rem_pio2f(x, &y) & 3)
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{
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case 0: return __cosdf(y);
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case 1: return __sindf(-y);
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case 2: return -__cosdf(y);
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default: return __sindf(y);
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}
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}
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/* origin: FreeBSD /usr/src/lib/msun/src/s_cos.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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fn double _cos(double x) @weak @nostrip
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{
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// High word of x.
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uint ix = (uint)(bitcast(x, ulong) >> 32);
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ix &= 0x7fffffff;
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switch
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{
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// |x| ~< pi/4
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case ix <= 0x3fe921fb:
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if (ix < 0x3e46a09e)
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{
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// |x| < 2**-27 * sqrt(2)
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// raise inexact if x!=0
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force_eval_add(x, 0x1p120f);
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return 1.0;
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}
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return __cos(x, 0);
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case ix >= 0x7ff00000:
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// cos(Inf or NaN) is NaN
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return x - x;
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default:
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// argument reduction
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double[2] y @noinit;
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switch (__rem_pio2(x, &y) & 3)
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{
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case 0: return __cos(y[0], y[1]);
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case 1: return -__sin(y[0], y[1], 1);
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case 2: return -__cos(y[0], y[1]);
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default: return __sin(y[0], y[1], 1);
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}
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}
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}
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