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glibc  2.9
k_sinf.c
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00001 /* k_sinf.c -- float version of k_sin.c
00002  * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
00003  */
00004 
00005 /*
00006  * ====================================================
00007  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
00008  *
00009  * Developed at SunPro, a Sun Microsystems, Inc. business.
00010  * Permission to use, copy, modify, and distribute this
00011  * software is freely granted, provided that this notice 
00012  * is preserved.
00013  * ====================================================
00014  */
00015 
00016 #if defined(LIBM_SCCS) && !defined(lint)
00017 static char rcsid[] = "$NetBSD: k_sinf.c,v 1.4 1995/05/10 20:46:33 jtc Exp $";
00018 #endif
00019 
00020 #include "math.h"
00021 #include "math_private.h"
00022 
00023 #ifdef __STDC__
00024 static const float 
00025 #else
00026 static float 
00027 #endif
00028 half =  5.0000000000e-01,/* 0x3f000000 */
00029 S1  = -1.6666667163e-01, /* 0xbe2aaaab */
00030 S2  =  8.3333337680e-03, /* 0x3c088889 */
00031 S3  = -1.9841270114e-04, /* 0xb9500d01 */
00032 S4  =  2.7557314297e-06, /* 0x3638ef1b */
00033 S5  = -2.5050759689e-08, /* 0xb2d72f34 */
00034 S6  =  1.5896910177e-10; /* 0x2f2ec9d3 */
00035 
00036 #ifdef __STDC__
00037        float __kernel_sinf(float x, float y, int iy)
00038 #else
00039        float __kernel_sinf(x, y, iy)
00040        float x,y; int iy;          /* iy=0 if y is zero */
00041 #endif
00042 {
00043        float z,r,v;
00044        int32_t ix;
00045        GET_FLOAT_WORD(ix,x);
00046        ix &= 0x7fffffff;                  /* high word of x */
00047        if(ix<0x32000000)                  /* |x| < 2**-27 */
00048           {if((int)x==0) return x;}              /* generate inexact */
00049        z      =  x*x;
00050        v      =  z*x;
00051        r      =  S2+z*(S3+z*(S4+z*(S5+z*S6)));
00052        if(iy==0) return x+v*(S1+z*r);
00053        else      return x-((z*(half*y-v*r)-y)-v*S1);
00054 }