11dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* @(#)s_frexp.c 5.1 93/09/24 */ 21dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* 31dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ==================================================== 41dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 51dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * 61dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Developed at SunPro, a Sun Microsystems, Inc. business. 71dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * Permission to use, copy, modify, and distribute this 81dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * software is freely granted, provided that this notice 91dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * is preserved. 101dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * ==================================================== 111dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 121dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 13a0ee07829a9ba7e99ef68e8c12551301cc797f0fElliott Hughes#include <sys/cdefs.h> 14a0ee07829a9ba7e99ef68e8c12551301cc797f0fElliott Hughes__FBSDID("$FreeBSD$"); 151dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 161dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project/* 171dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * for non-zero x 181dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * x = frexp(arg,&exp); 191dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * return a double fp quantity x such that 0.5 <= |x| <1.0 201dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * and the corresponding binary exponent "exp". That is 211dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * arg = x*2^exp. 221dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * If arg is inf, 0.0, or NaN, then frexp(arg,&exp) returns arg 231dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project * with *exp=0. 241dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project */ 251dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 261dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include <float.h> 271dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 281dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "math.h" 291dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#include "math_private.h" 301dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 311dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectstatic const double 321dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projecttwo54 = 1.80143985094819840000e+16; /* 0x43500000, 0x00000000 */ 331dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 341dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectdouble 351dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Projectfrexp(double x, int *eptr) 361dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project{ 371dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project int32_t hx, ix, lx; 381dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project EXTRACT_WORDS(hx,lx,x); 391dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ix = 0x7fffffff&hx; 401dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *eptr = 0; 411dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if(ix>=0x7ff00000||((ix|lx)==0)) return x; /* 0,inf,nan */ 421dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project if (ix<0x00100000) { /* subnormal */ 431dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project x *= two54; 441dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project GET_HIGH_WORD(hx,x); 451dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project ix = hx&0x7fffffff; 461dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *eptr = -54; 471dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project } 481dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project *eptr += (ix>>20)-1022; 491dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project hx = (hx&0x800fffff)|0x3fe00000; 501dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project SET_HIGH_WORD(x,hx); 511dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project return x; 521dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project} 531dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project 541dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#if (LDBL_MANT_DIG == 53) 551dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project__weak_reference(frexp, frexpl); 561dc9e472e19acfe6dc7f41e429236e7eef7ceda1The Android Open Source Project#endif 57