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 /* 15 * truncf(x) 16 * Return x rounded toward 0 to integral value 17 * Method: 18 * Bit twiddling. 19 * Exception: 20 * Inexact flag raised if x not equal to truncf(x). 21 */ 22 23 #include "math.h" 24 #include "math_private.h" 25 26 static const float huge = 1.0e30F; 27 28 float 29 truncf(float x) 30 { 31 int32_t i0,j0; 32 u_int32_t i; 33 GET_FLOAT_WORD(i0,x); 34 j0 = ((i0>>23)&0xff)-0x7f; 35 if(j0<23) { 36 if(j0<0) { /* raise inexact if x != 0 */ 37 if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ 38 i0 &= 0x80000000; 39 } else { 40 i = (0x007fffff)>>j0; 41 if((i0&i)==0) return x; /* x is integral */ 42 if(huge+x>0.0F) /* raise inexact flag */ 43 i0 &= (~i); 44 } 45 } else { 46 if(j0==0x80) return x+x; /* inf or NaN */ 47 else return x; /* x is integral */ 48 } 49 SET_FLOAT_WORD(x,i0); 50 return x; 51 } 52