1d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol/* sf_scalbn.c -- float version of s_scalbn.c. 2d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol */ 4d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 5d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol/* 6d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * ==================================================== 7d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * 9d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * Developed at SunPro, a Sun Microsystems, Inc. business. 10d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * Permission to use, copy, modify, and distribute this 11d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * software is freely granted, provided that this notice 12d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * is preserved. 13d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol * ==================================================== 14d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol */ 15d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 16d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#include "fdlibm.h" 17d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#include <limits.h> 18d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#include <float.h> 19d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 20d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#if INT_MAX > 50000 21d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#define OVERFLOW_INT 50000 22d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#else 23d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#define OVERFLOW_INT 30000 24d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#endif 25d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 26d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#ifdef __STDC__ 27d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignolstatic const float 28d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#else 29d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignolstatic float 30d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#endif 31d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignoltwo25 = 3.355443200e+07, /* 0x4c000000 */ 32d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignoltwom25 = 2.9802322388e-08, /* 0x33000000 */ 33d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignolhuge = 1.0e+30, 34d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignoltiny = 1.0e-30; 35d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 36d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#ifdef __STDC__ 37d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol float scalbnf (float x, int n) 38d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#else 39d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol float scalbnf (x,n) 40d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol float x; int n; 41d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#endif 42d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol{ 43d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol __int32_t k,ix; 44d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol __uint32_t hx; 45d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 46d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol GET_FLOAT_WORD(ix,x); 47d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol hx = ix&0x7fffffff; 48d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol k = hx>>23; /* extract exponent */ 49d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (FLT_UWORD_IS_ZERO(hx)) 50d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol return x; 51d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (!FLT_UWORD_IS_FINITE(hx)) 52d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol return x+x; /* NaN or Inf */ 53d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (FLT_UWORD_IS_SUBNORMAL(hx)) { 54d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol x *= two25; 55d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol GET_FLOAT_WORD(ix,x); 56d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol k = ((ix&0x7f800000)>>23) - 25; 57d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (n< -50000) return tiny*x; /*underflow*/ 58d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol } 59d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol k = k+n; 60d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (k > FLT_LARGEST_EXP) return huge*copysignf(huge,x); /* overflow */ 61d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (k > 0) /* normal result */ 62d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol {SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); return x;} 63d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (k < FLT_SMALLEST_EXP) { 64d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol if (n > OVERFLOW_INT) /* in case integer overflow in n+k */ 65d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol return huge*copysignf(huge,x); /*overflow*/ 66d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol else return tiny*copysignf(tiny,x); /*underflow*/ 67d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol } 68d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol k += 25; /* subnormal result */ 69d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol SET_FLOAT_WORD(x,(ix&0x807fffff)|(k<<23)); 70d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol return x*twom25; 71d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol} 72d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 73d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#ifdef _DOUBLE_IS_32BITS 74d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 75d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#ifdef __STDC__ 76d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol double scalbn(double x, int n) 77d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#else 78d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol double scalbn(x,n) 79d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol double x; 80d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol int n; 81d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#endif 82d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol{ 83d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol return (double) scalbnf((float) x, n); 84d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol} 85d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol 86d61f9ebd0671c1066118199537cd6057ecbf8697Andrew Rossignol#endif /* defined(_DOUBLE_IS_32BITS) */ 87