sysdeps/ieee754/flt-32/s_rintf.c

   1 /* s_rintf.c -- float version of s_rint.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 <math.h>
  17 #include <math_private.h>
  18
  19 static const float
  20 TWO23[2]={
  21   8.3886080000e+06, /* 0x4b000000 */
  22  -8.3886080000e+06, /* 0xcb000000 */
  23 };
  24
  25 float
  26 __rintf(float x)
  27 {
  28         int32_t i0,j0,sx;
  29         float w,t;
  30         GET_FLOAT_WORD(i0,x);
  31         sx = (i0>>31)&1;
  32         j0 = ((i0>>23)&0xff)-0x7f;
  33         if(j0<23) {
  34             if(j0<0) {
  35                 w = TWO23[sx]+x;
  36                 t =  w-TWO23[sx];
  37                 GET_FLOAT_WORD(i0,t);
  38                 SET_FLOAT_WORD(t,(i0&0x7fffffff)|(sx<<31));
  39                 return t;
  40             }
  41         } else {
  42             if(j0==0x80) return x+x;    /* inf or NaN */
  43             else return x;              /* x is integral */
  44         }
  45         w = TWO23[sx]+x;
  46         return w-TWO23[sx];
  47 }
  48 #ifndef __rintf
  49 weak_alias (__rintf, rintf)
  50 #endif