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 * ====================================================
15 * FreeBSD SVN: 193368 (2009-06-03)
18 /* __libm_rem_pio2f(x,y)
20 * return the remainder of x rem pi/2 in *y
21 * use double precision for everything except passing x
22 * use __kernel_rem_pio2() for large x
26 #include "math_private.h"
29 * invpio2: 53 bits of 2/pi
30 * pio2_1: first 33 bit of pi/2
31 * pio2_1t: pi/2 - pio2_1
35 invpio2 = 6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */
36 pio2_1 = 1.57079631090164184570e+00, /* 0x3FF921FB, 0x50000000 */
37 pio2_1t = 1.58932547735281966916e-08; /* 0x3E5110b4, 0x611A6263 */
39 #ifndef INLINE_REM_PIO2F
43 __libm_rem_pio2f(float x, double *y)
52 /* 33+53 bit pi is good enough for medium size */
53 if(ix<0x4dc90fdb) { /* |x| ~< 2^28*(pi/2), medium size */
54 /* Use a specialized rint() to get fn. Assume round-to-nearest. */
55 STRICT_ASSIGN(double,fn,x*invpio2+0x1.8p52);
57 #ifdef HAVE_EFFICIENT_IRINT
68 * all other (large) arguments
70 if(ix>=0x7f800000) { /* x is inf or NaN */
73 /* set z = scalbn(|x|,ilogb(|x|)-23) */
74 e0 = (ix>>23)-150; /* e0 = ilogb(|x|)-23; */
75 SET_FLOAT_WORD(z, ix - ((int32_t)(e0<<23)));
77 n = __kernel_rem_pio2(tx,ty,e0,1,0);
78 if(hx<0) {*y = -ty[0]; return -n;}