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-rw-r--r--src/math/k_sin.c68
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diff --git a/src/math/k_sin.c b/src/math/k_sin.c
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-
-/* @(#)k_sin.c 1.3 95/01/18 */
-/*
- * ====================================================
- * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
- *
- * Developed at SunSoft, a Sun Microsystems, Inc. business.
- * Permission to use, copy, modify, and distribute this
- * software is freely granted, provided that this notice
- * is preserved.
- * ====================================================
- */
-
-/* __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"
-
-static const double
-half = 5.00000000000000000000e-01, /* 0x3FE00000, 0x00000000 */
-S1 = -1.66666666666666324348e-01, /* 0xBFC55555, 0x55555549 */
-S2 = 8.33333333332248946124e-03, /* 0x3F811111, 0x1110F8A6 */
-S3 = -1.98412698298579493134e-04, /* 0xBF2A01A0, 0x19C161D5 */
-S4 = 2.75573137070700676789e-06, /* 0x3EC71DE3, 0x57B1FE7D */
-S5 = -2.50507602534068634195e-08, /* 0xBE5AE5E6, 0x8A2B9CEB */
-S6 = 1.58969099521155010221e-10; /* 0x3DE5D93A, 0x5ACFD57C */
-
-double
-__kernel_sin(double x, double y, int iy)
-{
- double z,r,v;
- 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;
- 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);
-}