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 #if 0 15 __FBSDID("$FreeBSD: src/lib/msun/src/s_truncf.c,v 1.1 2004/06/20 09:25:43 das Exp $"); 16 #endif 17 #if defined(LIBM_SCCS) && !defined(lint) 18 __RCSID("$NetBSD: s_truncf.c,v 1.4 2008/04/25 22:21:53 christos Exp $"); 19 #endif 20 21 /* 22 * truncf(x) 23 * Return x rounded toward 0 to integral value 24 * Method: 25 * Bit twiddling. 26 * Exception: 27 * Inexact flag raised if x not equal to truncf(x). 28 */ 29 30 #include "math.h" 31 #include "math_private.h" 32 33 static const float huge = 1.0e30F; 34 35 float 36 truncf(float x) 37 { 38 int32_t i0,jj0; 39 uint32_t i; 40 GET_FLOAT_WORD(i0,x); 41 jj0 = ((i0>>23)&0xff)-0x7f; 42 if(jj0<23) { 43 if(jj0<0) { /* raise inexact if x != 0 */ 44 if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ 45 i0 &= 0x80000000; 46 } else { 47 i = (0x007fffff)>>jj0; 48 if((i0&i)==0) return x; /* x is integral */ 49 if(huge+x>0.0F) /* raise inexact flag */ 50 i0 &= (~i); 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 return x; 58 } 59