| /* e_rem_pio2f.c -- float version of e_rem_pio2.c |
| * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. |
| * Debugged and optimized by Bruce D. Evans. |
| */ |
| |
| /* |
| * ==================================================== |
| * 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. |
| * ==================================================== |
| */ |
| |
| #include <sys/cdefs.h> |
| __FBSDID("$FreeBSD$"); |
| |
| /* __ieee754_rem_pio2f(x,y) |
| * |
| * return the remainder of x rem pi/2 in *y |
| * use double precision for everything except passing x |
| * use __kernel_rem_pio2() for large x |
| */ |
| |
| #include <float.h> |
| |
| #include "math.h" |
| #include "math_private.h" |
| |
| /* |
| * invpio2: 53 bits of 2/pi |
| * pio2_1: first 25 bits of pi/2 |
| * pio2_1t: pi/2 - pio2_1 |
| */ |
| |
| static const double |
| invpio2 = 6.36619772367581382433e-01, /* 0x3FE45F30, 0x6DC9C883 */ |
| pio2_1 = 1.57079631090164184570e+00, /* 0x3FF921FB, 0x50000000 */ |
| pio2_1t = 1.58932547735281966916e-08; /* 0x3E5110b4, 0x611A6263 */ |
| |
| #ifdef INLINE_REM_PIO2F |
| static __inline __always_inline |
| #endif |
| int |
| __ieee754_rem_pio2f(float x, double *y) |
| { |
| double w,r,fn; |
| double tx[1],ty[1]; |
| float z; |
| int32_t e0,n,ix,hx; |
| |
| GET_FLOAT_WORD(hx,x); |
| ix = hx&0x7fffffff; |
| /* 33+53 bit pi is good enough for medium size */ |
| if(ix<0x4dc90fdb) { /* |x| ~< 2^28*(pi/2), medium size */ |
| /* Use a specialized rint() to get fn. Assume round-to-nearest. */ |
| STRICT_ASSIGN(double,fn,x*invpio2+0x1.8p52); |
| fn = fn-0x1.8p52; |
| #ifdef HAVE_EFFICIENT_IRINT |
| n = irint(fn); |
| #else |
| n = (int32_t)fn; |
| #endif |
| r = x-fn*pio2_1; |
| w = fn*pio2_1t; |
| *y = r-w; |
| return n; |
| } |
| /* |
| * all other (large) arguments |
| */ |
| if(ix>=0x7f800000) { /* x is inf or NaN */ |
| *y=x-x; return 0; |
| } |
| /* set z = scalbn(|x|,ilogb(|x|)-23) */ |
| e0 = (ix>>23)-150; /* e0 = ilogb(|x|)-23; */ |
| SET_FLOAT_WORD(z, ix - ((int32_t)(e0<<23))); |
| tx[0] = z; |
| n = __kernel_rem_pio2(tx,ty,e0,1,0); |
| if(hx<0) {*y = -ty[0]; return -n;} |
| *y = ty[0]; return n; |
| } |
