diff options
Diffstat (limited to 'libjava/classpath/native/fdlibm/k_cos.c')
| -rw-r--r-- | libjava/classpath/native/fdlibm/k_cos.c | 33 |
1 files changed, 16 insertions, 17 deletions
diff --git a/libjava/classpath/native/fdlibm/k_cos.c b/libjava/classpath/native/fdlibm/k_cos.c index acf50a82e83..3ddc298975c 100644 --- a/libjava/classpath/native/fdlibm/k_cos.c +++ b/libjava/classpath/native/fdlibm/k_cos.c @@ -1,12 +1,12 @@ -/* @(#)k_cos.c 5.1 93/09/24 */ +/* @(#)k_cos.c 1.4 96/03/07 */ /* * ==================================================== * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. * - * Developed at SunPro, a Sun Microsystems, Inc. business. + * Developed at SunSoft, a Sun Microsystems, Inc. business. * Permission to use, copy, modify, and distribute this - * software is freely granted, provided that this notice + * software is freely granted, provided that this notice * is preserved. * ==================================================== */ @@ -15,7 +15,7 @@ * __kernel_cos( x, y ) * kernel cos function on [-pi/4, pi/4], pi/4 ~ 0.785398164 * Input x is assumed to be bounded by ~pi/4 in magnitude. - * Input y is the tail of x. + * Input y is the tail of x. * * Algorithm * 1. Since cos(-x) = cos(x), we need only to consider positive x. @@ -24,16 +24,16 @@ * [0,pi/4] * 4 14 * cos(x) ~ 1 - x*x/2 + C1*x + ... + C6*x - * where the remez error is - * + * where the Remes error is + * * | 2 4 6 8 10 12 14 | -58 * |cos(x)-(1-.5*x +C1*x +C2*x +C3*x +C4*x +C5*x +C6*x )| <= 2 - * | | - * - * 4 6 8 10 12 14 + * | | + * + * 4 6 8 10 12 14 * 4. let r = C1*x +C2*x +C3*x +C4*x +C5*x +C6*x , then * cos(x) = 1 - x*x/2 + r - * since cos(x+y) ~ cos(x) - sin(x)*y + * since cos(x+y) ~ cos(x) - sin(x)*y * ~ cos(x) - x*y, * a correction term is necessary in cos(x) and hence * cos(x+y) = 1 - (x*x/2 - (r - x*y)) @@ -51,9 +51,9 @@ #ifndef _DOUBLE_IS_32BITS #ifdef __STDC__ -static const double +static const double #else -static double +static double #endif one = 1.00000000000000000000e+00, /* 0x3FF00000, 0x00000000 */ C1 = 4.16666666666666019037e-02, /* 0x3FA55555, 0x5555554C */ @@ -72,25 +72,24 @@ C6 = -1.13596475577881948265e-11; /* 0xBDA8FAE9, 0xBE8838D4 */ { double a,hz,z,r,qx; int32_t ix; - GET_HIGH_WORD(ix,x); - ix &= 0x7fffffff; /* ix = |x|'s high word*/ + GET_HIGH_WORD(ix, x); + ix &= 0x7fffffff; /* ix = |x|'s high word*/ if(ix<0x3e400000) { /* if x < 2**27 */ if(((int)x)==0) return one; /* generate inexact */ } z = x*x; r = z*(C1+z*(C2+z*(C3+z*(C4+z*(C5+z*C6))))); - if(ix < 0x3FD33333) /* if |x| < 0.3 */ + if(ix < 0x3FD33333) /* if |x| < 0.3 */ return one - (0.5*z - (z*r - x*y)); else { if(ix > 0x3fe90000) { /* x > 0.78125 */ qx = 0.28125; } else { - INSERT_WORDS(qx,ix-0x00200000,0); /* x/4 */ + INSERT_WORDS(qx,ix-0x00200000,0); } hz = 0.5*z-qx; a = one-qx; return a - (hz - (z*r-x*y)); } } - #endif /* defined(_DOUBLE_IS_32BITS) */ |
