1 /* s_floorf.c -- float version of s_floor.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 <sys/cdefs.h> 17 #if defined(LIBM_SCCS) && !defined(lint) 18 __RCSID("$NetBSD: s_floorf.c,v 1.7 2002/05/26 22:01:56 wiz Exp $"); 19 #endif 20 21 /* 22 * floorf(x) 23 * Return x rounded toward -inf to integral value 24 * Method: 25 * Bit twiddling. 26 * Exception: 27 * Inexact flag raised if x not equal to floorf(x). 28 */ 29 30 #include "math.h" 31 #include "math_private.h" 32 33 static const float huge = 1.0e30; 34 35 float 36 floorf(float x) 37 { 38 int32_t i0,j0; 39 u_int32_t i; 40 GET_FLOAT_WORD(i0,x); 41 j0 = ((i0>>23)&0xff)-0x7f; 42 if(j0<23) { 43 if(j0<0) { /* raise inexact if x != 0 */ 44 if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */ 45 if(i0>=0) {i0=0;} 46 else if((i0&0x7fffffff)!=0) 47 { i0=0xbf800000;} 48 } 49 } else { 50 i = (0x007fffff)>>j0; 51 if((i0&i)==0) return x; /* x is integral */ 52 if(huge+x>(float)0.0) { /* raise inexact flag */ 53 if(i0<0) i0 += (0x00800000)>>j0; 54 i0 &= (~i); 55 } 56 } 57 } else { 58 if(j0==0x80) return x+x; /* inf or NaN */ 59 else return x; /* x is integral */ 60 } 61 SET_FLOAT_WORD(x,i0); 62 return x; 63 } 64