--- /dev/null
+/* Split a double into fraction and mantissa, for hexadecimal printf.
+ 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
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ 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>
+
+#if !(defined USE_LONG_DOUBLE && !HAVE_LONG_DOUBLE)
+
+/* Specification. */
+# ifdef USE_LONG_DOUBLE
+# include "printf-frexpl.h"
+# else
+# include "printf-frexp.h"
+# endif
+
+# include <float.h>
+# include <math.h>
+# include "verify.h"
+
+/* This file assumes FLT_RADIX is 2. */
+verify (FLT_RADIX == 2);
+
+# ifdef USE_LONG_DOUBLE
+# define FUNC printf_frexpl
+# define DOUBLE long double
+# define MIN_EXP LDBL_MIN_EXP
+# if HAVE_FREXPL_IN_LIBC && HAVE_LDEXPL_IN_LIBC
+# define USE_FREXP_LDEXP
+# define FREXP frexpl
+# define LDEXP ldexpl
+# endif
+# define L_(literal) literal##L
+# else
+# define FUNC printf_frexp
+# define DOUBLE double
+# define MIN_EXP DBL_MIN_EXP
+# if HAVE_FREXP_IN_LIBC && HAVE_LDEXP_IN_LIBC
+# define USE_FREXP_LDEXP
+# define FREXP frexp
+# define LDEXP ldexp
+# endif
+# define L_(literal) literal
+# endif
+
+DOUBLE
+FUNC (DOUBLE x, int *exp)
+{
+ int exponent;
+
+# ifdef USE_FREXP_LDEXP
+ /* frexp and ldexp are usually faster than the loop below. */
+ x = FREXP (x, &exponent);
+
+ x = x + x;
+ exponent -= 1;
+
+ if (exponent < MIN_EXP - 1)
+ {
+ x = LDEXP (x, exponent - (MIN_EXP - 1));
+ exponent = MIN_EXP - 1;
+ }
+# else
+ /* Since the exponent is an 'int', it fits in 64 bits. Therefore the
+ loops are executed no more than 64 times. */
+ DOUBLE pow2[64]; /* pow2[i] = 2^2^i */
+ DOUBLE powh[64]; /* powh[i] = 2^-2^i */
+ int i;
+
+ exponent = 0;
+ if (x >= L_(1.0))
+ {
+ /* A nonnegative exponent. */
+ {
+ DOUBLE pow2_i; /* = pow2[i] */
+ DOUBLE powh_i; /* = powh[i] */
+
+ /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i,
+ x * 2^exponent = argument, x >= 1.0. */
+ for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5);
+ ;
+ i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i)
+ {
+ if (x >= pow2_i)
+ {
+ exponent += (1 << i);
+ x *= powh_i;
+ }
+ else
+ break;
+
+ pow2[i] = pow2_i;
+ powh[i] = powh_i;
+ }
+ }
+ /* Here 1.0 <= x < 2^2^i. */
+ }
+ else
+ {
+ /* A negative exponent. */
+ {
+ DOUBLE pow2_i; /* = pow2[i] */
+ DOUBLE powh_i; /* = powh[i] */
+
+ /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i,
+ x * 2^exponent = argument, x < 1.0, exponent >= MIN_EXP - 1. */
+ for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5);
+ ;
+ i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i)
+ {
+ if (exponent - (1 << i) < MIN_EXP - 1)
+ break;
+
+ exponent -= (1 << i);
+ x *= pow2_i;
+ if (x >= L_(1.0))
+ break;
+
+ pow2[i] = pow2_i;
+ powh[i] = powh_i;
+ }
+ }
+ /* Here either x < 1.0 and exponent - 2^i < MIN_EXP - 1 <= exponent,
+ or 1.0 <= x < 2^2^i and exponent >= MIN_EXP - 1. */
+
+ if (x < L_(1.0))
+ /* Invariants: x * 2^exponent = argument, x < 1.0 and
+ exponent - 2^i < MIN_EXP - 1 <= exponent. */
+ while (i > 0)
+ {
+ i--;
+ if (exponent - (1 << i) >= MIN_EXP - 1)
+ {
+ exponent -= (1 << i);
+ x *= pow2[i];
+ if (x >= L_(1.0))
+ break;
+ }
+ }
+
+ /* Here either x < 1.0 and exponent = MIN_EXP - 1,
+ or 1.0 <= x < 2^2^i and exponent >= MIN_EXP - 1. */
+ }
+
+ /* Invariants: x * 2^exponent = argument, and
+ either x < 1.0 and exponent = MIN_EXP - 1,
+ or 1.0 <= x < 2^2^i and exponent >= MIN_EXP - 1. */
+ while (i > 0)
+ {
+ i--;
+ if (x >= pow2[i])
+ {
+ exponent += (1 << i);
+ x *= powh[i];
+ }
+ }
+ /* Here either x < 1.0 and exponent = MIN_EXP - 1,
+ or 1.0 <= x < 2.0 and exponent >= MIN_EXP - 1. */
+# endif
+
+ *exp = exponent;
+ return x;
+}
+
+#else
+
+/* This declaration is solely to ensure that after preprocessing
+ this file is never empty. */
+typedef int dummy;
+
+#endif
--- /dev/null
+/* Split a double into fraction and mantissa, for hexadecimal printf.
+ 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
+ the Free Software Foundation; either version 2, or (at your option)
+ any later version.
+
+ This program 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+/* Write a finite, positive number x as
+ x = mantissa * 2^exp
+ where exp >= DBL_MIN_EXP - 1,
+ mantissa < 2.0,
+ if x is not a denormalized number then mantissa >= 1.0.
+ Store exp and return mantissa. */
+extern double printf_frexp (double x, int *exp);
--- /dev/null
+# printf-frexp.m4 serial 1
+dnl Copyright (C) 2007 Free Software Foundation, Inc.
+dnl This file is free software; the Free Software Foundation
+dnl gives unlimited permission to copy and/or distribute it,
+dnl with or without modifications, as long as this notice is preserved.
+
+dnl Check how to define printf_frexp() without linking with libm.
+
+AC_DEFUN([gl_FUNC_PRINTF_FREXP],
+[
+ AC_CACHE_CHECK([whether frexp can be used without linking with libm],
+ [gl_cv_func_frexp_no_libm],
+ [
+ AC_TRY_LINK([#include <math.h>
+ double x;
+ int y;],
+ [return frexp (x, &y) < 1;],
+ [gl_cv_func_frexp_no_libm=yes],
+ [gl_cv_func_frexp_no_libm=no])
+ ])
+ if test $gl_cv_func_frexp_no_libm = yes; then
+ AC_DEFINE([HAVE_FREXP_IN_LIBC], 1,
+ [Define if the frexp function is available in libc.])
+ fi
+
+ AC_CACHE_CHECK([whether ldexp can be used without linking with libm],
+ [gl_cv_func_ldexp_no_libm],
+ [
+ AC_TRY_LINK([#include <math.h>
+ double x;
+ int y;],
+ [return ldexp (x, y) < 1;],
+ [gl_cv_func_ldexp_no_libm=yes],
+ [gl_cv_func_ldexp_no_libm=no])
+ ])
+ if test $gl_cv_func_ldexp_no_libm = yes; then
+ AC_DEFINE([HAVE_LDEXP_IN_LIBC], 1,
+ [Define if the ldexp function is available in libc.])
+ fi
+])
projects / gnulib.git / commitdiff