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 /* 17 * floorf(x) 18 * Return x rounded toward -inf to integral value 19 * Method: 20 * Bit twiddling. 21 * Exception: 22 * Inexact flag raised if x not equal to floorf(x). 23 */ 24 25 #include "math.h" 26 #include "math_private.h" 27 28 static const float huge = 1.0e30; 29 30 float 31 floorf(float x) 32 { 33 int32_t i0,j0; 34 u_int32_t i; 35 GET_FLOAT_WORD(i0,x); 36 j0 = ((i0>>23)&0xff)-0x7f; 37 if(j0<23) { 38 if(j0<0) { /* raise inexact if x != 0 */ 39 if(huge+x>(float)0.0) {/* return 0*sign(x) if |x|<1 */ 40 if(i0>=0) {i0=0;} 41 else if((i0&0x7fffffff)!=0) 42 { i0=0xbf800000;} 43 } 44 } else { 45 i = (0x007fffff)>>j0; 46 if((i0&i)==0) return x; /* x is integral */ 47 if(huge+x>(float)0.0) { /* raise inexact flag */ 48 if(i0<0) i0 += (0x00800000)>>j0; 49 i0 &= (~i); 50 } 51 } 52 } else { 53 if(j0==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