1 /* @(#)s_floor.c 5.1 93/09/24 */ 2 /* 3 * ==================================================== 4 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 5 * 6 * Developed at SunPro, a Sun Microsystems, Inc. business. 7 * Permission to use, copy, modify, and distribute this 8 * software is freely granted, provided that this notice 9 * is preserved. 10 * ==================================================== 11 */ 12 13 #include <sys/cdefs.h> 14 /* __FBSDID("$FreeBSD: src/lib/msun/src/s_truncf.c,v 1.1 2004/06/20 09:25:43 das Exp $"); */ 15 16 /* 17 * truncf(x) 18 * Return x rounded toward 0 to integral value 19 * Method: 20 * Bit twiddling. 21 * Exception: 22 * Inexact flag raised if x not equal to truncf(x). 23 */ 24 25 #include "math.h" 26 #include "math_private.h" 27 28 static const float huge = 1.0e30F; 29 30 float 31 truncf(float x) 32 { 33 int32_t i0,j0; 34 u_int32_t i; 35 GET_FLOAT_WORD(i0,x); 36 j0 = ((i0>>23)&0xff)-0x7f; 37 if(j0<23) { 38 if(j0<0) { /* raise inexact if x != 0 */ 39 if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ 40 i0 &= 0x80000000; 41 } else { 42 i = (0x007fffff)>>j0; 43 if((i0&i)==0) return x; /* x is integral */ 44 if(huge+x>0.0F) /* raise inexact flag */ 45 i0 &= (~i); 46 } 47 } else { 48 if(j0==0x80) return x+x; /* inf or NaN */ 49 else return x; /* x is integral */ 50 } 51 SET_FLOAT_WORD(x,i0); 52 return x; 53 } 54
