[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: new module 'frexp'
From: |
Bruno Haible |
Subject: |
Re: new module 'frexp' |
Date: |
Thu, 22 Mar 2007 13:23:24 +0100 |
User-agent: |
KMail/1.5.4 |
Paolo Bonzini wrote:
> I don't mind your stuff being used in the frexpl module (which would then
> be turned into LGPL).
There is no frexpl module so far. This does the first part of the change.
2007-03-22 Bruno Haible <address@hidden>
* lib/frexpl.c: Share code with lib/frexp.c.
* modules/mathl (Files): Add lib/frexp.c.
(Depends-on): Add isnanl-nolibm.
*** lib/frexpl.c 24 Feb 2007 16:31:38 -0000 1.6
--- lib/frexpl.c 22 Mar 2007 12:20:32 -0000
***************
*** 1,9 ****
! /* Emulation for frexpl.
! Contributed by Paolo Bonzini
!
! Copyright 2002, 2003, 2007 Free Software Foundation, Inc.
!
! This file is part of gnulib.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
--- 1,5 ----
! /* Split a 'long double' into fraction and mantissa.
! Copyright (C) 2007 Free Software Foundation, Inc.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
***************
*** 19,107 ****
with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
! #include <config.h>
!
! /* Specification. */
! #include <math.h>
!
! #include <float.h>
!
! /* Binary search. Quite inefficient but portable. */
! long double
! frexpl(long double x, int *exp)
! {
! /* Since the exponent is an 'int', it fits in 64 bits. Therefore the
! loops are executed no more than 64 times. */
! long double exponents[64];
! long double *next;
! int exponent, bit;
!
! /* Check for zero, nan and infinity. */
! if (x != x || x + x == x)
! {
! *exp = 0;
! return x;
! }
!
! if (x < 0)
! return -frexpl(-x, exp);
!
! exponent = 0;
! if (x >= 1.0)
! {
! for (next = exponents, exponents[0] = 2.0L, bit = 1;
! *next <= x + x;
! bit <<= 1, next[1] = next[0] * next[0], next++);
!
! for (; next >= exponents; bit >>= 1, next--)
! if (x + x >= *next)
! {
! x /= *next;
! exponent |= bit;
! }
!
! }
!
! else if (x < 0.5)
! {
! for (next = exponents, exponents[0] = 0.5L, bit = 1;
! *next > x;
! bit <<= 1, next[1] = next[0] * next[0], next++);
!
! for (; next >= exponents; bit >>= 1, next--)
! if (x < *next)
! {
! x /= *next;
! exponent |= bit;
! }
!
! exponent = -exponent;
! }
!
! *exp = exponent;
! return x;
! }
!
! #if 0
! int
! main (void)
! {
! long double x;
! int y;
! x = frexpl(0.0L / 0.0L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(1.0L / 0.0L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(-1.0L / 0.0L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(0.5L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(0.75L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(1.0L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(3.6L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(17.8L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(8.0L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(0.3L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(0.49L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(0.049L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(0.0245L, &y); printf ("%.6Lg %d\n", x, y);
! x = frexpl(0.0625L, &y); printf ("%.6Lg %d\n", x, y);
! }
! #endif
!
--- 15,19 ----
with this program; if not, write to the Free Software Foundation,
Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
! #define USE_LONG_DOUBLE
! #include "frexp.c"
*** modules/mathl 18 Feb 2007 15:10:28 -0000 1.5
--- modules/mathl 22 Mar 2007 12:20:32 -0000
***************
*** 10,15 ****
--- 10,16 ----
lib/expl.c
lib/floorl.c
lib/frexpl.c
+ lib/frexp.c
lib/ldexpl.c
lib/logl.c
lib/sincosl.c
***************
*** 22,27 ****
--- 23,29 ----
Depends-on:
math
+ isnanl-nolibm
configure.ac:
gl_FUNC_LONG_DOUBLE_MATH