Line data    Source code

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