s_scalbnf.c revision 97413
12116Sjkh/* s_scalbnf.c -- float version of s_scalbn.c. 22116Sjkh * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 32116Sjkh */ 42116Sjkh 52116Sjkh/* 62116Sjkh * ==================================================== 72116Sjkh * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 82116Sjkh * 92116Sjkh * Developed at SunPro, a Sun Microsystems, Inc. business. 102116Sjkh * Permission to use, copy, modify, and distribute this 118870Srgrimes * software is freely granted, provided that this notice 122116Sjkh * is preserved. 132116Sjkh * ==================================================== 142116Sjkh */ 152116Sjkh 162116Sjkh#ifndef lint 1750476Speterstatic char rcsid[] = "$FreeBSD: head/lib/msun/src/s_scalbnf.c 97413 2002-05-28 18:15:04Z alfred $"; 182116Sjkh#endif 192116Sjkh 202116Sjkh#include "math.h" 212116Sjkh#include "math_private.h" 222116Sjkh 232116Sjkhstatic const float 242116Sjkhtwo25 = 3.355443200e+07, /* 0x4c000000 */ 252116Sjkhtwom25 = 2.9802322388e-08, /* 0x33000000 */ 262116Sjkhhuge = 1.0e+30, 272116Sjkhtiny = 1.0e-30; 282116Sjkh 2997413Salfredfloat 3097413Salfredscalbnf (float x, int n) 312116Sjkh{ 322116Sjkh int32_t k,ix; 332116Sjkh GET_FLOAT_WORD(ix,x); 342116Sjkh k = (ix&0x7f800000)>>23; /* extract exponent */ 352116Sjkh if (k==0) { /* 0 or subnormal x */ 362116Sjkh if ((ix&0x7fffffff)==0) return x; /* +-0 */ 372116Sjkh x *= two25; 382116Sjkh GET_FLOAT_WORD(ix,x); 398870Srgrimes k = ((ix&0x7f800000)>>23) - 25; 402116Sjkh if (n< -50000) return tiny*x; /*underflow*/ 412116Sjkh } 422116Sjkh if (k==0xff) return x+x; /* NaN or Inf */ 438870Srgrimes k = k+n; 442116Sjkh if (k > 0xfe) return huge*copysignf(huge,x); /* overflow */ 452116Sjkh if (k > 0) /* normal result */ 462116Sjkh {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;} 472116Sjkh if (k <= -25) 482116Sjkh if (n > 50000) /* in case integer overflow in n+k */ 492116Sjkh return huge*copysignf(huge,x); /*overflow*/ 502116Sjkh else return tiny*copysignf(tiny,x); /*underflow*/ 512116Sjkh k += 25; /* subnormal result */ 522116Sjkh SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); 532116Sjkh return x*twom25; 542116Sjkh} 55