1 /* 2 * ==================================================== 3 * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved. 4 * 5 * Developed at SunPro, a Sun Microsystems, Inc. business. 6 * Permission to use, copy, modify, and distribute this 7 * software is freely granted, provided that this notice 8 * is preserved. 9 * ==================================================== 10 */ 11 12 #include <sys/cdefs.h> 13 /* 14 * truncf(x) 15 * Return x rounded toward 0 to integral value 16 * Method: 17 * Bit twiddling. 18 * Exception: 19 * Inexact flag raised if x not equal to truncf(x). 20 */ 21 22 #include "math.h" 23 #include "math_private.h" 24 25 static const float huge = 1.0e30F; 26 27 float 28 truncf(float x) 29 { 30 int32_t i0,j0; 31 u_int32_t i; 32 GET_FLOAT_WORD(i0,x); 33 j0 = ((i0>>23)&0xff)-0x7f; 34 if(j0<23) { 35 if(j0<0) { /* raise inexact if x != 0 */ 36 if(huge+x>0.0F) /* |x|<1, so return 0*sign(x) */ 37 i0 &= 0x80000000; 38 } else { 39 i = (0x007fffff)>>j0; 40 if((i0&i)==0) return x; /* x is integral */ 41 if(huge+x>0.0F) /* raise inexact flag */ 42 i0 &= (~i); 43 } 44 } else { 45 if(j0==0x80) return x+x; /* inf or NaN */ 46 else return x; /* x is integral */ 47 } 48 SET_FLOAT_WORD(x,i0); 49 return x; 50 } 51