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 #if 0 14 #include <sys/cdefs.h> 15 __FBSDID("$FreeBSD: src/lib/msun/src/s_truncf.c,v 1.1 2004/06/20 09:25:43 das Exp $"); 16 #endif 17 #include <sys/cdefs.h> 18 #if defined(LIBM_SCCS) && !defined(lint) 19 __RCSID("$NetBSD: s_truncf.c,v 1.2 2006/03/25 16:55:53 xtraeme Exp $"); 20 #endif 21 22 /* 23 * truncf(x) 24 * Return x rounded toward 0 to integral value 25 * Method: 26 * Bit twiddling. 27 * Exception: 28 * Inexact flag raised if x not equal to truncf(x). 29 */ 30 31 #include "math.h" 32 #include "math_private.h" 33 34 static const float huge = 1.0e30F; 35 36 float 37 truncf(float x) 38 { 39 int32_t i0,j0; 40 uint32_t i; 41 GET_FLOAT_WORD(i0,x); 42 j0 = ((i0>>23)&0xff)-0x7f; 43 if(j0<23) { 44 if(j0<0) { /* raise inexact if x != 0 */ 45 if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ 46 i0 &= 0x80000000; 47 } else { 48 i = (0x007fffff)>>j0; 49 if((i0&i)==0) return x; /* x is integral */ 50 if(huge+x>0.0F) /* raise inexact flag */ 51 i0 &= (~i); 52 } 53 } else { 54 if(j0==0x80) return x+x; /* inf or NaN */ 55 else return x; /* x is integral */ 56 } 57 SET_FLOAT_WORD(x,i0); 58 return x; 59 } 60