X-Git-Url: http://erislabs.net/gitweb/?a=blobdiff_plain;f=lib%2Fprintf-frexp.c;h=7f7e0ecde40efb6e5da1119def493c8b8b8e8a8c;hb=4470580881a7b821b52fb5635102ef3e27aa5af4;hp=427ee9485a860fbe7d9b539a42a93f07702b6e89;hpb=e5de8bf80c52f872c5ca944db9bf3fd28993bd2e;p=gnulib.git
diff --git a/lib/printf-frexp.c b/lib/printf-frexp.c
index 427ee9485..7f7e0ecde 100644
--- a/lib/printf-frexp.c
+++ b/lib/printf-frexp.c
@@ -1,66 +1,75 @@
/* Split a double into fraction and mantissa, for hexadecimal printf.
- Copyright (C) 2007 Free Software Foundation, Inc.
+ Copyright (C) 2007, 2009-2011 Free Software Foundation, Inc.
- This program is free software; you can redistribute it and/or modify
+ 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.
+ the Free Software Foundation; either version 3 of the License, 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. */
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see . */
#include
-#if !(defined USE_LONG_DOUBLE && !HAVE_LONG_DOUBLE)
-
/* Specification. */
-# ifdef USE_LONG_DOUBLE
-# include "printf-frexpl.h"
-# else
-# include "printf-frexp.h"
-# endif
+#ifdef USE_LONG_DOUBLE
+# include "printf-frexpl.h"
+#else
+# include "printf-frexp.h"
+#endif
-# include
-# include
-# 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
+#include
+#include
+#ifdef USE_LONG_DOUBLE
+# include "fpucw.h"
+#endif
+
+/* This file assumes FLT_RADIX = 2. If FLT_RADIX is a power of 2 greater
+ than 2, or not even a power of 2, some rounding errors can occur, so that
+ then the returned mantissa is only guaranteed to be <= 2.0, not < 2.0. */
+
+#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 DECL_ROUNDING DECL_LONG_DOUBLE_ROUNDING
+# define BEGIN_ROUNDING() BEGIN_LONG_DOUBLE_ROUNDING ()
+# define END_ROUNDING() END_LONG_DOUBLE_ROUNDING ()
+# 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 DECL_ROUNDING
+# define BEGIN_ROUNDING()
+# define END_ROUNDING()
+# define L_(literal) literal
+#endif
DOUBLE
-FUNC (DOUBLE x, int *exp)
+FUNC (DOUBLE x, int *expptr)
{
int exponent;
+ DECL_ROUNDING
-# ifdef USE_FREXP_LDEXP
+ BEGIN_ROUNDING ();
+
+#ifdef USE_FREXP_LDEXP
/* frexp and ldexp are usually faster than the loop below. */
x = FREXP (x, &exponent);
@@ -72,112 +81,108 @@ FUNC (DOUBLE x, int *exp)
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. */
+#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))
{
- 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;
- }
+ /* 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. */
}
- /* Here 1.0 <= x < 2^2^i. */
- }
- else
- {
- /* A negative exponent. */
+ else
{
- 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;
- }
+ /* 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. */
}
- /* 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
+ /* 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;
+ END_ROUNDING ();
+
+ *expptr = exponent;
return x;
}
-
-#else
-
-/* This declaration is solely to ensure that after preprocessing
- this file is never empty. */
-typedef int dummy;
-
-#endif