1 /* e_rem_pio2f.c -- float version of e_rem_pio2.c
2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com.
3 * Debugged and optimized by Bruce D. Evans.
7 * ====================================================
8 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
10 * Developed at SunPro, a Sun Microsystems, Inc. business.
11 * Permission to use, copy, modify, and distribute this
12 * software is freely granted, provided that this notice
14 * ====================================================
16 * $FreeBSD: head/lib/msun/src/e_rem_pio2f.c 239195 2012-08-11 15:47:22Z dim $
19 /* __ieee754_rem_pio2f(x,y)
21 * return the remainder of x rem pi/2 in *y
22 * use double precision for everything except passing x
23 * use __kernel_rem_pio2() for large x
29 #include "math_private.h"
32 * invpio2: 53 bits of 2/pi
33 * pio2_1: first 25 bits of pi/2
34 * pio2_1t: pi/2 - pio2_1
38 invpio2 = 6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */
39 pio2_1 = 1.57079631090164184570e+00, /* 0x3FF921FB, 0x50000000 */
40 pio2_1t = 1.58932547735281966916e-08; /* 0x3E5110b4, 0x611A6263 */
42 #ifdef INLINE_REM_PIO2F
43 static __inline __always_inline
46 __ieee754_rem_pio2f(float x, double *y)
55 /* 33+53 bit pi is good enough for medium size */
56 if(ix<0x4dc90fdb) { /* |x| ~< 2^28*(pi/2), medium size */
57 /* Use a specialized rint() to get fn. Assume round-to-nearest. */
58 STRICT_ASSIGN(double,fn,x*invpio2+0x1.8p52);
60 #ifdef HAVE_EFFICIENT_IRINT
71 * all other (large) arguments
73 if(ix>=0x7f800000) { /* x is inf or NaN */
76 /* set z = scalbn(|x|,ilogb(|x|)-23) */
77 e0 = (ix>>23)-150; /* e0 = ilogb(|x|)-23; */
78 SET_FLOAT_WORD(z, ix - ((int32_t)(e0<<23)));
80 n = __kernel_rem_pio2(tx,ty,e0,1,0);
81 if(hx<0) {*y = -ty[0]; return -n;}