octave-kai/gnulib-hg: lib/printf-frexp.c annotate

annotate lib/printf-frexp.c @ 9309:bbbbbf4cd1c5

Change copyright notice from GPLv2+ to GPLv3+.

author	Bruno Haible <bruno@clisp.org>
date	Sun, 07 Oct 2007 19:14:58 +0200
parents	359d135f748c
children	bec01fc15c2f

rev	line source
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	1 /* Split a double into fraction and mantissa, for hexadecimal printf.
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	2 Copyright (C) 2007 Free Software Foundation, Inc.
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	3
9309 bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 8648 diff changeset	4 This program is free software: you can redistribute it and/or modify
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	5 it under the terms of the GNU General Public License as published by
9309 bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 8648 diff changeset	6 the Free Software Foundation; either version 3 of the License, or
bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 8648 diff changeset	7 (at your option) any later version.
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	8
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	9 This program is distributed in the hope that it will be useful,
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	10 but WITHOUT ANY WARRANTY; without even the implied warranty of
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	12 GNU General Public License for more details.
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	13
9309 bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 8648 diff changeset	14 You should have received a copy of the GNU General Public License
bbbbbf4cd1c5 Change copyright notice from GPLv2+ to GPLv3+. Bruno Haible <bruno@clisp.org> parents: 8648 diff changeset	15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	16
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	17 #include <config.h>
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	18
8648 359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	19 /* Specification. */
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	20 #ifdef USE_LONG_DOUBLE
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	21 # include "printf-frexpl.h"
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	22 #else
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	23 # include "printf-frexp.h"
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	24 #endif
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	25
8648 359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	26 #include <float.h>
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	27 #include <math.h>
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	28 #ifdef USE_LONG_DOUBLE
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	29 # include "fpucw.h"
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	30 #endif
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	31
8253 c59696ff6dbc Add comment about FLT_RADIX. Bruno Haible <bruno@clisp.org> parents: 8252 diff changeset	32 /* This file assumes FLT_RADIX = 2. If FLT_RADIX is a power of 2 greater
c59696ff6dbc Add comment about FLT_RADIX. Bruno Haible <bruno@clisp.org> parents: 8252 diff changeset	33 than 2, or not even a power of 2, some rounding errors can occur, so that
c59696ff6dbc Add comment about FLT_RADIX. Bruno Haible <bruno@clisp.org> parents: 8252 diff changeset	34 then the returned mantissa is only guaranteed to be <= 2.0, not < 2.0. */
c59696ff6dbc Add comment about FLT_RADIX. Bruno Haible <bruno@clisp.org> parents: 8252 diff changeset	35
8648 359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	36 #ifdef USE_LONG_DOUBLE
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	37 # define FUNC printf_frexpl
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	38 # define DOUBLE long double
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	39 # define MIN_EXP LDBL_MIN_EXP
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	40 # if HAVE_FREXPL_IN_LIBC && HAVE_LDEXPL_IN_LIBC
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	41 # define USE_FREXP_LDEXP
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	42 # define FREXP frexpl
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	43 # define LDEXP ldexpl
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	44 # endif
8648 359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	45 # define DECL_ROUNDING DECL_LONG_DOUBLE_ROUNDING
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	46 # define BEGIN_ROUNDING() BEGIN_LONG_DOUBLE_ROUNDING ()
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	47 # define END_ROUNDING() END_LONG_DOUBLE_ROUNDING ()
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	48 # define L_(literal) literal##L
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	49 #else
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	50 # define FUNC printf_frexp
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	51 # define DOUBLE double
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	52 # define MIN_EXP DBL_MIN_EXP
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	53 # if HAVE_FREXP_IN_LIBC && HAVE_LDEXP_IN_LIBC
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	54 # define USE_FREXP_LDEXP
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	55 # define FREXP frexp
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	56 # define LDEXP ldexp
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	57 # endif
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	58 # define DECL_ROUNDING
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	59 # define BEGIN_ROUNDING()
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	60 # define END_ROUNDING()
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	61 # define L_(literal) literal
359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	62 #endif
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	63
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	64 DOUBLE
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	65 FUNC (DOUBLE x, int *exp)
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	66 {
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	67 int exponent;
8531 52719799a90e New module 'fpucw'. Bruno Haible <bruno@clisp.org> parents: 8362 diff changeset	68 DECL_ROUNDING
52719799a90e New module 'fpucw'. Bruno Haible <bruno@clisp.org> parents: 8362 diff changeset	69
52719799a90e New module 'fpucw'. Bruno Haible <bruno@clisp.org> parents: 8362 diff changeset	70 BEGIN_ROUNDING ();
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	71
8648 359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	72 #ifdef USE_FREXP_LDEXP
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	73 /* frexp and ldexp are usually faster than the loop below. */
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	74 x = FREXP (x, &exponent);
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	75
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	76 x = x + x;
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	77 exponent -= 1;
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	78
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	79 if (exponent < MIN_EXP - 1)
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	80 {
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	81 x = LDEXP (x, exponent - (MIN_EXP - 1));
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	82 exponent = MIN_EXP - 1;
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	83 }
8648 359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	84 #else
8535 530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	85 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	86 /* Since the exponent is an 'int', it fits in 64 bits. Therefore the
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	87 loops are executed no more than 64 times. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	88 DOUBLE pow2[64]; /* pow2[i] = 2^2^i */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	89 DOUBLE powh[64]; /* powh[i] = 2^-2^i */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	90 int i;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	91
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	92 exponent = 0;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	93 if (x >= L_(1.0))
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	94 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	95 /* A nonnegative exponent. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	96 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	97 DOUBLE pow2_i; /* = pow2[i] */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	98 DOUBLE powh_i; /* = powh[i] */
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	99
8535 530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	100 /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i,
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	101 x * 2^exponent = argument, x >= 1.0. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	102 for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5);
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	103 ;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	104 i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i)
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	105 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	106 if (x >= pow2_i)
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	107 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	108 exponent += (1 << i);
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	109 x *= powh_i;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	110 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	111 else
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	112 break;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	113
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	114 pow2[i] = pow2_i;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	115 powh[i] = powh_i;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	116 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	117 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	118 /* Here 1.0 <= x < 2^2^i. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	119 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	120 else
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	121 {
8535 530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	122 /* A negative exponent. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	123 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	124 DOUBLE pow2_i; /* = pow2[i] */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	125 DOUBLE powh_i; /* = powh[i] */
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	126
8535 530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	127 /* Invariants: pow2_i = 2^2^i, powh_i = 2^-2^i,
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	128 x * 2^exponent = argument, x < 1.0, exponent >= MIN_EXP - 1. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	129 for (i = 0, pow2_i = L_(2.0), powh_i = L_(0.5);
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	130 ;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	131 i++, pow2_i = pow2_i * pow2_i, powh_i = powh_i * powh_i)
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	132 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	133 if (exponent - (1 << i) < MIN_EXP - 1)
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	134 break;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	135
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	136 exponent -= (1 << i);
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	137 x *= pow2_i;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	138 if (x >= L_(1.0))
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	139 break;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	140
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	141 pow2[i] = pow2_i;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	142 powh[i] = powh_i;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	143 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	144 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	145 /* Here either x < 1.0 and exponent - 2^i < MIN_EXP - 1 <= exponent,
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	146 or 1.0 <= x < 2^2^i and exponent >= MIN_EXP - 1. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	147
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	148 if (x < L_(1.0))
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	149 /* Invariants: x * 2^exponent = argument, x < 1.0 and
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	150 exponent - 2^i < MIN_EXP - 1 <= exponent. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	151 while (i > 0)
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	152 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	153 i--;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	154 if (exponent - (1 << i) >= MIN_EXP - 1)
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	155 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	156 exponent -= (1 << i);
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	157 x *= pow2[i];
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	158 if (x >= L_(1.0))
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	159 break;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	160 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	161 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	162
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	163 /* Here either x < 1.0 and exponent = MIN_EXP - 1,
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	164 or 1.0 <= x < 2^2^i and exponent >= MIN_EXP - 1. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	165 }
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	166
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	167 /* Invariants: x * 2^exponent = argument, and
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	168 either x < 1.0 and exponent = MIN_EXP - 1,
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	169 or 1.0 <= x < 2^2^i and exponent >= MIN_EXP - 1. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	170 while (i > 0)
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	171 {
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	172 i--;
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	173 if (x >= pow2[i])
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	174 {
8535 530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	175 exponent += (1 << i);
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	176 x *= powh[i];
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	177 }
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	178 }
8535 530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	179 /* Here either x < 1.0 and exponent = MIN_EXP - 1,
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	180 or 1.0 <= x < 2.0 and exponent >= MIN_EXP - 1. */
530583a3b054 Oops, fix ANSI C syntax error introduced in last patch. Bruno Haible <bruno@clisp.org> parents: 8531 diff changeset	181 }
8648 359d135f748c Assume 'long double' exists. Bruno Haible <bruno@clisp.org> parents: 8535 diff changeset	182 #endif
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	183
8531 52719799a90e New module 'fpucw'. Bruno Haible <bruno@clisp.org> parents: 8362 diff changeset	184 END_ROUNDING ();
52719799a90e New module 'fpucw'. Bruno Haible <bruno@clisp.org> parents: 8362 diff changeset	185
8240 536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	186 *exp = exponent;
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	187 return x;
536315dcb204 New module 'printf-frexp'. Bruno Haible <bruno@clisp.org> parents: diff changeset	188 }

Mercurial > hg > octave-kai > gnulib-hg

annotate lib/printf-frexp.c @ 9309:bbbbbf4cd1c5