sysdeps/ieee754/flt-32/s_rintf.c

   1 /* s_rintf.c -- float version of s_rint.c.
   2  */
   3
   4 /*
   5  * ====================================================
   6  * Copyright (C) 1993 by Sun Microsystems, Inc. All rights reserved.
   7  *
   8  * Developed at SunPro, a Sun Microsystems, Inc. business.
   9  * Permission to use, copy, modify, and distribute this
  10  * software is freely granted, provided that this notice
  11  * is preserved.
  12  * ====================================================
  13  */
  14
  15 #define NO_MATH_REDIRECT
  16 #include <math.h>
  17 #include <math_private.h>
  18 #include <libm-alias-float.h>
  19 #include <math-use-builtins.h>
  20
  21 float
  22 __rintf (float x)
  23 {
  24 #if USE_RINTF_BUILTIN
  25   return __builtin_rintf (x);
  26 #else
  27   /* Use generic implementation.  */
  28   static const float
  29     TWO23[2] = {
  30                 8.3886080000e+06, /* 0x4b000000 */
  31                 -8.3886080000e+06, /* 0xcb000000 */
  32   };
  33   int32_t i0, j0, sx;
  34   float w, t;
  35   GET_FLOAT_WORD (i0, x);
  36   sx = (i0 >> 31) & 1;
  37   j0 = ((i0 >> 23) & 0xff) - 0x7f;
  38   if (j0 < 23)
  39     {
  40       if(j0 < 0)
  41         {
  42           w = TWO23[sx] + x;
  43           t =  w - TWO23[sx];
  44           GET_FLOAT_WORD (i0, t);
  45           SET_FLOAT_WORD (t, (i0 & 0x7fffffff) | (sx << 31));
  46           return t;
  47         }
  48     }
  49   else
  50     {
  51       if (j0 == 0x80)
  52         return x + x;           /* inf or NaN  */
  53       else
  54         return x;               /* x is integral  */
  55     }
  56   w = TWO23[sx] + x;
  57   return w - TWO23[sx];
  58 #endif /* ! USE_RINTF_BUILTIN  */
  59 }
  60 #ifndef __rintf
  61 libm_alias_float (__rint, rint)
  62 #endif