Line data    Source code

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