s_rintf.c (1102B)
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,j0,sx; 29 volatile float w,t; /* volatile works around gcc bug */ 30 GET_FLOAT_WORD(i0,x); 31 sx = (i0>>31)&1; 32 j0 = ((i0>>23)&0xff)-0x7f; 33 if(j0<23) { 34 if(j0<0) { 35 if((i0&0x7fffffff)==0) return x; 36 w = TWO23[sx]+x; 37 t = w-TWO23[sx]; 38 return t; 39 } 40 w = TWO23[sx]+x; 41 return w-TWO23[sx]; 42 } 43 if(j0==0x80) return x+x; /* inf or NaN */ 44 else return x; /* x is integral */ 45 }