about summary refs log tree commit diff
path: root/sysdeps/ieee754/dbl-64/s_exp2.c
diff options
context:
space:
mode:
Diffstat (limited to 'sysdeps/ieee754/dbl-64/s_exp2.c')
-rw-r--r--sysdeps/ieee754/dbl-64/s_exp2.c130
1 files changed, 0 insertions, 130 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_exp2.c b/sysdeps/ieee754/dbl-64/s_exp2.c
deleted file mode 100644
index d02af15ecc..0000000000
--- a/sysdeps/ieee754/dbl-64/s_exp2.c
+++ /dev/null
@@ -1,130 +0,0 @@
-/* Double-precision floating point 2^x.
-   Copyright (C) 1997, 1998, 2000 Free Software Foundation, Inc.
-   This file is part of the GNU C Library.
-   Contributed by Geoffrey Keating <geoffk@ozemail.com.au>
-
-   The GNU C Library is free software; you can redistribute it and/or
-   modify it under the terms of the GNU Library General Public License as
-   published by the Free Software Foundation; either version 2 of the
-   License, or (at your option) any later version.
-
-   The GNU C Library is distributed in the hope that it will be useful,
-   but WITHOUT ANY WARRANTY; without even the implied warranty of
-   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
-   Library General Public License for more details.
-
-   You should have received a copy of the GNU Library General Public
-   License along with the GNU C Library; see the file COPYING.LIB.  If not,
-   write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
-
-/* The basic design here is from
-   Shmuel Gal and Boris Bachelis, "An Accurate Elementary Mathematical
-   Library for the IEEE Floating Point Standard", ACM Trans. Math. Soft.,
-   17 (1), March 1991, pp. 26-45.
-   It has been slightly modified to compute 2^x instead of e^x.
-   */
-#ifndef _GNU_SOURCE
-#define _GNU_SOURCE
-#endif
-#include <stdlib.h>
-#include <float.h>
-#include <ieee754.h>
-#include <math.h>
-#include <fenv.h>
-#include <inttypes.h>
-#include <math_private.h>
-
-#include "t_exp2.h"
-
-static const volatile double TWO1023 = 8.988465674311579539e+307;
-static const volatile double TWOM1000 = 9.3326361850321887899e-302;
-
-double
-__ieee754_exp2 (double x)
-{
-  static const double himark = (double) DBL_MAX_EXP;
-  static const double lomark = (double) (DBL_MIN_EXP - DBL_MANT_DIG - 1) - 1.0;
-
-  /* Check for usual case.  */
-  if (isless (x, himark) && isgreater (x, lomark))
-    {
-      static const double THREEp42 = 13194139533312.0;
-      int tval, unsafe;
-      double rx, x22, result;
-      union ieee754_double ex2_u, scale_u;
-      fenv_t oldenv;
-
-      feholdexcept (&oldenv);
-#ifdef FE_TONEAREST
-      /* If we don't have this, it's too bad.  */
-      fesetround (FE_TONEAREST);
-#endif
-
-      /* 1. Argument reduction.
-	 Choose integers ex, -256 <= t < 256, and some real
-	 -1/1024 <= x1 <= 1024 so that
-	 x = ex + t/512 + x1.
-
-	 First, calculate rx = ex + t/512.  */
-      rx = x + THREEp42;
-      rx -= THREEp42;
-      x -= rx;  /* Compute x=x1. */
-      /* Compute tval = (ex*512 + t)+256.
-	 Now, t = (tval mod 512)-256 and ex=tval/512  [that's mod, NOT %; and
-	 /-round-to-nearest not the usual c integer /].  */
-      tval = (int) (rx * 512.0 + 256.0);
-
-      /* 2. Adjust for accurate table entry.
-	 Find e so that
-	 x = ex + t/512 + e + x2
-	 where -1e6 < e < 1e6, and
-	 (double)(2^(t/512+e))
-	 is accurate to one part in 2^-64.  */
-
-      /* 'tval & 511' is the same as 'tval%512' except that it's always
-	 positive.
-	 Compute x = x2.  */
-      x -= exp2_deltatable[tval & 511];
-
-      /* 3. Compute ex2 = 2^(t/512+e+ex).  */
-      ex2_u.d = exp2_accuratetable[tval & 511];
-      tval >>= 9;
-      unsafe = abs(tval) >= -DBL_MIN_EXP - 1;
-      ex2_u.ieee.exponent += tval >> unsafe;
-      scale_u.d = 1.0;
-      scale_u.ieee.exponent += tval - (tval >> unsafe);
-
-      /* 4. Approximate 2^x2 - 1, using a fourth-degree polynomial,
-	 with maximum error in [-2^-10-2^-30,2^-10+2^-30]
-	 less than 10^-19.  */
-
-      x22 = (((.0096181293647031180
-	       * x + .055504110254308625)
-	      * x + .240226506959100583)
-	     * x + .69314718055994495) * ex2_u.d;
-
-      /* 5. Return (2^x2-1) * 2^(t/512+e+ex) + 2^(t/512+e+ex).  */
-      fesetenv (&oldenv);
-
-      result = x22 * x + ex2_u.d;
-
-      if (!unsafe)
-	return result;
-      else
-	return result * scale_u.d;
-    }
-  /* Exceptional cases:  */
-  else if (isless (x, himark))
-    {
-      if (__isinf (x))
-	/* e^-inf == 0, with no error.  */
-	return 0;
-      else
-	/* Underflow */
-	return TWOM1000 * TWOM1000;
-    }
-  else
-    /* Return x, if x is a NaN or Inf; or overflow, otherwise.  */
-    return TWO1023*x;
-}