Mercurial > hg > octave-lojdl > gnulib-hg
changeset 8492:1dcdd2ec146b
Tests for module 'frexp'.
author | Bruno Haible <bruno@clisp.org> |
---|---|
date | Thu, 22 Mar 2007 04:02:05 +0000 |
parents | af98e0b44387 |
children | c62e99bf6912 |
files | ChangeLog modules/frexp-tests tests/test-frexp.c |
diffstat | 3 files changed, 203 insertions(+), 0 deletions(-) [+] |
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--- a/ChangeLog +++ b/ChangeLog @@ -1,5 +1,8 @@ 2007-03-21 Bruno Haible <bruno@clisp.org> + * modules/frexp-tests: New file. + * tests/test-frexp.c: New file. + * modules/frexp: New file. * lib/frexp.c: New file. * m4/frexp.m4: New file.
new file mode 100644 --- /dev/null +++ b/modules/frexp-tests @@ -0,0 +1,15 @@ +Files: +tests/test-frexp.c + +Depends-on: + +configure.ac: +AC_SUBST([FREXP_LIBM]) + +Makefile.am: +TESTS += test-frexp +check_PROGRAMS += test-frexp +test_frexp_LDADD = @FREXP_LIBM@ $(LDADD) + +License: +LGPL
new file mode 100644 --- /dev/null +++ b/tests/test-frexp.c @@ -0,0 +1,185 @@ +/* Test of splitting a 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 + 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. */ + +/* Written by Bruno Haible <bruno@clisp.org>, 2007. */ + +#include <config.h> + +#include <math.h> + +#include <float.h> +#include <stdlib.h> + +#define ASSERT(expr) if (!(expr)) abort (); + +static double +my_ldexp (double x, int d) +{ + for (; d > 0; d--) + x *= 2.0; + for (; d < 0; d++) + x *= 0.5; + return x; +} + +int +main () +{ + int i; + /* The use of 'volatile' guarantees that excess precision bits are dropped + when dealing with denormalized numbers. It is necessary on x86 systems + where double-floats are not IEEE compliant by default, to avoid that the + results become platform and compiler option dependent. 'volatile' is a + portable alternative to gcc's -ffloat-store option. */ + volatile double x; + + { /* NaN. */ + int exp = -9999; + double mantissa; + x = 0.0 / 0.0; + mantissa = frexp (x, &exp); + ASSERT (mantissa != mantissa); + } + + { /* Positive infinity. */ + int exp = -9999; + double mantissa; + x = 1.0 / 0.0; + mantissa = frexp (x, &exp); + ASSERT (mantissa == x); + } + + { /* Negative infinity. */ + int exp = -9999; + double mantissa; + x = -1.0 / 0.0; + mantissa = frexp (x, &exp); + ASSERT (mantissa == x); + } + + { /* Positive zero. */ + int exp = -9999; + double mantissa; + x = 0.0; + mantissa = frexp (x, &exp); + ASSERT (exp == 0); + ASSERT (mantissa == x); + } + + { /* Negative zero. */ + int exp = -9999; + double mantissa; + x = -0.0; + mantissa = frexp (x, &exp); + ASSERT (exp == 0); + ASSERT (mantissa == x); + } + + for (i = 1, x = 1.0; i <= DBL_MAX_EXP; i++, x *= 2.0) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == 0.5); + } + for (i = 1, x = 1.0; i >= DBL_MIN_EXP; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == 0.5); + } + for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == 0.5); + } + + for (i = 1, x = -1.0; i <= DBL_MAX_EXP; i++, x *= 2.0) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == -0.5); + } + for (i = 1, x = -1.0; i >= DBL_MIN_EXP; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == -0.5); + } + for (; i >= DBL_MIN_EXP - 100 && x < 0.0; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == -0.5); + } + + for (i = 1, x = 1.01; i <= DBL_MAX_EXP; i++, x *= 2.0) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == 0.505); + } + for (i = 1, x = 1.01; i >= DBL_MIN_EXP; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == 0.505); + } + for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa >= 0.5); + ASSERT (mantissa < 1.0); + ASSERT (mantissa == my_ldexp (x, - exp)); + } + + for (i = 1, x = 1.73205; i <= DBL_MAX_EXP; i++, x *= 2.0) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == 0.866025); + } + for (i = 1, x = 1.73205; i >= DBL_MIN_EXP; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == 0.866025); + } + for (; i >= DBL_MIN_EXP - 100 && x > 0.0; i--, x *= 0.5) + { + int exp = -9999; + double mantissa = frexp (x, &exp); + ASSERT (exp == i || exp == i + 1); + ASSERT (mantissa >= 0.5); + ASSERT (mantissa < 1.0); + ASSERT (mantissa == my_ldexp (x, - exp)); + } + + return 0; +}