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 #include <sys/cdefs.h> 17 #if defined(LIBM_SCCS) && !defined(lint) 18 __RCSID("$NetBSD: s_rintf.c,v 1.5 1997/10/09 11:33:13 lukem Exp $"); 19 #endif 20 21 #include "math.h" 22 #include "math_private.h" 23 24 #ifdef __STDC__ 25 static const float 26 #else 27 static float 28 #endif 29 TWO23[2]={ 30 8.3886080000e+06, /* 0x4b000000 */ 31 -8.3886080000e+06, /* 0xcb000000 */ 32 }; 33 34 #ifdef __STDC__ 35 float rintf(float x) 36 #else 37 float rintf(x) 38 float x; 39 #endif 40 { 41 int32_t i0,j0,sx; 42 u_int32_t i,i1; 43 float w,t; 44 GET_FLOAT_WORD(i0,x); 45 sx = (i0>>31)&1; 46 j0 = ((i0>>23)&0xff)-0x7f; 47 if(j0<23) { 48 if(j0<0) { 49 if((i0&0x7fffffff)==0) return x; 50 i1 = (i0&0x07fffff); 51 i0 &= 0xfff00000; 52 i0 |= ((i1|-i1)>>9)&0x400000; 53 SET_FLOAT_WORD(x,i0); 54 w = TWO23[sx]+x; 55 t = w-TWO23[sx]; 56 GET_FLOAT_WORD(i0,t); 57 SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31)); 58 return t; 59 } else { 60 i = (0x007fffff)>>j0; 61 if((i0&i)==0) return x; /* x is integral */ 62 i>>=1; 63 if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>j0); 64 } 65 } else { 66 if(j0==0x80) return x+x; /* inf or NaN */ 67 else return x; /* x is integral */ 68 } 69 SET_FLOAT_WORD(x,i0); 70 w = TWO23[sx]+x; 71 return w-TWO23[sx]; 72 } 73