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 18 /* 19 * truncf(x) 20 * Return x rounded toward 0 to integral value 21 * Method: 22 * Bit twiddling. 23 * Exception: 24 * Inexact flag raised if x not equal to truncf(x). 25 */ 26 27 #include "math.h" 28 #include "math_private.h" 29 30 static const float huge = 1.0e30F; 31 32 float 33 truncf(float x) 34 { 35 int32_t i0,jj0; 36 u_int32_t i; 37 GET_FLOAT_WORD(i0,x); 38 jj0 = ((i0>>23)&0xff)-0x7f; 39 if(jj0<23) { 40 if(jj0<0) { /* raise inexact if x != 0 */ 41 if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ 42 i0 &= 0x80000000; 43 } else { 44 i = (0x007fffff)>>jj0; 45 if((i0&i)==0) return x; /* x is integral */ 46 if(huge+x>0.0F) /* raise inexact flag */ 47 i0 &= (~i); 48 } 49 } else { 50 if(jj0==0x80) return x+x; /* inf or NaN */ 51 else return x; /* x is integral */ 52 } 53 SET_FLOAT_WORD(x,i0); 54 return x; 55 } 56