s_floorf.c (1521B)
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 #ifndef lint 17 static char rcsid[] = "$FreeBSD: src/lib/msun/src/s_floorf.c,v 1.7 2002/05/28 18:15:04 alfred Exp $"; 18 #endif 19 20 /* 21 * floorf(x) 22 * Return x rounded toward -inf to integral value 23 * Method: 24 * Bit twiddling. 25 * Exception: 26 * Inexact flag raised if x not equal to floorf(x). 27 */ 28 29 #include "math.h" 30 #include "math_private.h" 31 32 static const float huge = 1.0e30; 33 34 float 35 floorf(float x) 36 { 37 int32_t i0,j0; 38 u_int32_t i; 39 GET_FLOAT_WORD(i0,x); 40 j0 = ((i0>>23)&0xff)-0x7f; 41 if(j0<23) { 42 if(j0<0) { /* raise inexact if x != 0 */ 43 if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */ 44 if(i0>=0) {i0=0;} 45 else if((i0&0x7fffffff)!=0) 46 { i0=0xbf800000;} 47 } 48 } else { 49 i = (0x007fffff)>>j0; 50 if((i0&i)==0) return x; /* x is integral */ 51 if(huge+x>(float)0.0) { /* raise inexact flag */ 52 if(i0<0) i0 += (0x00800000)>>j0; 53 i0 &= (~i); 54 } 55 } 56 } else { 57 if(j0==0x80) return x+x; /* inf or NaN */ 58 else return x; /* x is integral */ 59 } 60 SET_FLOAT_WORD(x,i0); 61 return x; 62 }