diff options
Diffstat (limited to 'sysdeps/ieee754/dbl-64/k_sin.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/k_sin.c | 92 |
1 files changed, 1 insertions, 91 deletions
diff --git a/sysdeps/ieee754/dbl-64/k_sin.c b/sysdeps/ieee754/dbl-64/k_sin.c index 49c59228e0..cc5c205a5f 100644 --- a/sysdeps/ieee754/dbl-64/k_sin.c +++ b/sysdeps/ieee754/dbl-64/k_sin.c @@ -1,91 +1 @@ -/* @(#)k_sin.c 5.1 93/09/24 */ -/* - * ==================================================== - * 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. - * ==================================================== - */ -/* Modified by Naohiko Shimizu/Tokai University, Japan 1997/08/25, - for performance improvement on pipelined processors. -*/ - -#if defined(LIBM_SCCS) && !defined(lint) -static char rcsid[] = "$NetBSD: k_sin.c,v 1.8 1995/05/10 20:46:31 jtc Exp $"; -#endif - -/* __kernel_sin( x, y, iy) - * kernel sin function on [-pi/4, pi/4], pi/4 ~ 0.7854 - * Input x is assumed to be bounded by ~pi/4 in magnitude. - * Input y is the tail of x. - * Input iy indicates whether y is 0. (if iy=0, y assume to be 0). - * - * Algorithm - * 1. Since sin(-x) = -sin(x), we need only to consider positive x. - * 2. if x < 2^-27 (hx<0x3e400000 0), return x with inexact if x!=0. - * 3. sin(x) is approximated by a polynomial of degree 13 on - * [0,pi/4] - * 3 13 - * sin(x) ~ x + S1*x + ... + S6*x - * where - * - * |sin(x) 2 4 6 8 10 12 | -58 - * |----- - (1+S1*x +S2*x +S3*x +S4*x +S5*x +S6*x )| <= 2 - * | x | - * - * 4. sin(x+y) = sin(x) + sin'(x')*y - * ~ sin(x) + (1-x*x/2)*y - * For better accuracy, let - * 3 2 2 2 2 - * r = x *(S2+x *(S3+x *(S4+x *(S5+x *S6)))) - * then 3 2 - * sin(x) = x + (S1*x + (x *(r-y/2)+y)) - */ - -#include "math.h" -#include "math_private.h" - -#ifdef __STDC__ -static const double -#else -static double -#endif -S[] = { - 5.00000000000000000000e-01, /* 0x3FE00000, 0x00000000 */ - -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */ - 8.33333333332248946124e-03, /* 0x3F811111, 0x1110F8A6 */ - -1.98412698298579493134e-04, /* 0xBF2A01A0, 0x19C161D5 */ - 2.75573137070700676789e-06, /* 0x3EC71DE3, 0x57B1FE7D */ - -2.50507602534068634195e-08, /* 0xBE5AE5E6, 0x8A2B9CEB */ - 1.58969099521155010221e-10}; /* 0x3DE5D93A, 0x5ACFD57C */ - -#ifdef __STDC__ - double __kernel_sin(double x, double y, int iy) -#else - double __kernel_sin(x, y, iy) - double x,y; int iy; /* iy=0 if y is zero */ -#endif -{ - double z,r,v,z1,r1,r2; - int32_t ix; - GET_HIGH_WORD(ix,x); - ix &= 0x7fffffff; /* high word of x */ - if(ix<0x3e400000) /* |x| < 2**-27 */ - {if((int)x==0) return x;} /* generate inexact */ - z = x*x; - v = z*x; -#ifdef DO_NOT_USE_THIS - r = S2+z*(S3+z*(S4+z*(S5+z*S6))); - if(iy==0) return x+v*(S1+z*r); - else return x-((z*(half*y-v*r)-y)-v*S1); -#else - r1 = S[5]+z*S[6]; z1 = z*z*z; - r2 = S[3]+z*S[4]; - r = S[2] + z*r2 + z1*r1; - if(iy==0) return x+v*(S[1]+z*r); - else return x-((z*(S[0]*y-v*r)-y)-v*S[1]); -#endif -} +/* Not needed anymore. */ |