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