s_rintf.c revision 2117
1/* s_rintf.c -- float version of s_rint.c. 2 * Conversion to float by Ian Lance Taylor, Cygnus Support, ian@cygnus.com. 3 */ 4 5/* 6 * ==================================================== 7 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 8 * 9 * Developed at SunPro, a Sun Microsystems, Inc. business. 10 * Permission to use, copy, modify, and distribute this 11 * software is freely granted, provided that this notice 12 * is preserved. 13 * ==================================================== 14 */ 15 16#ifndef lint 17static char rcsid[] = "$Id: s_rintf.c,v 1.2 1994/08/18 23:07:17 jtc Exp $"; 18#endif 19 20#include "math.h" 21#include "math_private.h" 22 23#ifdef __STDC__ 24static const float 25#else 26static float 27#endif 28TWO23[2]={ 29 8.3886080000e+06, /* 0x4b000000 */ 30 -8.3886080000e+06, /* 0xcb000000 */ 31}; 32 33#ifdef __STDC__ 34 float rintf(float x) 35#else 36 float rintf(x) 37 float x; 38#endif 39{ 40 int32_t i0,j0,sx; 41 u_int32_t i,i1; 42 float w,t; 43 GET_FLOAT_WORD(i0,x); 44 sx = (i0>>31)&1; 45 j0 = ((i0>>23)&0xff)-0x7f; 46 if(j0<23) { 47 if(j0<0) { 48 if((i0&0x7fffffff)==0) return x; 49 i1 = (i0&0x07fffff); 50 i0 &= 0xfff00000; 51 i0 |= ((i1|-i1)>>9)&0x400000; 52 SET_FLOAT_WORD(x,i0); 53 w = TWO23[sx]+x; 54 t = w-TWO23[sx]; 55 GET_FLOAT_WORD(i0,t); 56 SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31)); 57 return t; 58 } else { 59 i = (0x007fffff)>>j0; 60 if((i0&i)==0) return x; /* x is integral */ 61 i>>=1; 62 if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>j0); 63 } 64 } else { 65 if(j0==0x80) return x+x; /* inf or NaN */ 66 else return x; /* x is integral */ 67 } 68 SET_FLOAT_WORD(x,i0); 69 w = TWO23[sx]+x; 70 return w-TWO23[sx]; 71} 72