56 lines
1.2 KiB
C
56 lines
1.2 KiB
C
/* @(#)s_cos.c 5.1 93/09/24 */
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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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#include <float.h>
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#include "math.h"
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#define INLINE_REM_PIO2
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#include "math_private.h"
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double cos(double x)
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{
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double y[2],z=0.0;
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int32_t n, ix;
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/* High word of x. */
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GET_HIGH_WORD(ix,x);
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/* |x| ~< pi/4 */
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ix &= 0x7fffffff;
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if(ix <= 0x3fe921fb) {
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if(ix<0x3e46a09e) /* if x < 2**-27 * sqrt(2) */
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if(((int)x)==0) return 1.0; /* generate inexact */
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return __kernel_cos(x,z);
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}
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/* cos(Inf or NaN) is NaN */
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else if (ix>=0x7ff00000) return x-x;
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/* argument reduction needed */
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else {
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n = __ieee754_rem_pio2(x,y);
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switch(n&3) {
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case 0: return __kernel_cos(y[0],y[1]);
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case 1: return -__kernel_sin(y[0],y[1],1);
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case 2: return -__kernel_cos(y[0],y[1]);
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default:
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return __kernel_sin(y[0],y[1],1);
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}
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}
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}
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/*
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#if (LDBL_MANT_DIG == 53)
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__weak_reference(cos, cosl);
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#endif
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*/
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