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 #if defined(LIBM_SCCS) && !defined(lint) 17 static char rcsid[] = "$NetBSD: s_rintf.c,v 1.4 1995/05/10 20:48:06 jtc Exp $"; 18 #endif 19 20 #include "math.h" 21 #include "math_private.h" 22 23 static const float 24 TWO23[2]={ 25 8.3886080000e+06, /* 0x4b000000 */ 26 -8.3886080000e+06, /* 0xcb000000 */ 27 }; 28 29 float 30 rintf(float x) 31 { 32 int32_t i0,jj0,sx; 33 u_int32_t i,i1; 34 float w,t; 35 GET_FLOAT_WORD(i0,x); 36 sx = (i0>>31)&1; 37 jj0 = ((i0>>23)&0xff)-0x7f; 38 if(jj0<23) { 39 if(jj0<0) { 40 if((i0&0x7fffffff)==0) return x; 41 i1 = (i0&0x07fffff); 42 i0 &= 0xfff00000; 43 i0 |= ((i1|-i1)>>9)&0x400000; 44 SET_FLOAT_WORD(x,i0); 45 w = TWO23[sx]+x; 46 t = w-TWO23[sx]; 47 GET_FLOAT_WORD(i0,t); 48 SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31)); 49 return t; 50 } else { 51 i = (0x007fffff)>>jj0; 52 if((i0&i)==0) return x; /* x is integral */ 53 i>>=1; 54 if((i0&i)!=0) i0 = (i0&(~i))|((0x100000)>>jj0); 55 } 56 } else { 57 if(jj0==0x80) return x+x; /* inf or NaN */ 58 else return x; /* x is integral */ 59 } 60 SET_FLOAT_WORD(x,i0); 61 w = TWO23[sx]+x; 62 return w-TWO23[sx]; 63 } 64