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Diffstat (limited to 'gnulib-tests/test-frexp.h')
| -rw-r--r-- | gnulib-tests/test-frexp.h | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/gnulib-tests/test-frexp.h b/gnulib-tests/test-frexp.h new file mode 100644 index 0000000..cdc6ea3 --- /dev/null +++ b/gnulib-tests/test-frexp.h @@ -0,0 +1,179 @@ +/* Test of splitting a double into fraction and mantissa. + Copyright (C) 2012-2022 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 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, see <https://www.gnu.org/licenses/>. */ + +static DOUBLE +my_ldexp (DOUBLE x, int d) +{ + for (; d > 0; d--) + x *= L_(2.0); + for (; d < 0; d++) + x *= L_(0.5); + return x; +} + +static void +test_function (void) +{ + int i; + VOLATILE DOUBLE x; + + { /* NaN. */ + int exp = -9999; + DOUBLE mantissa; + x = NAN; + mantissa = FREXP (x, &exp); + ASSERT (ISNAN (mantissa)); + } + + { /* Positive infinity. */ + int exp = -9999; + DOUBLE mantissa; + x = INFINITY; + mantissa = FREXP (x, &exp); + ASSERT (mantissa == x); + } + + { /* Negative infinity. */ + int exp = -9999; + DOUBLE mantissa; + x = - INFINITY; + mantissa = FREXP (x, &exp); + ASSERT (mantissa == x); + } + + { /* Positive zero. */ + int exp = -9999; + DOUBLE mantissa; + x = L_(0.0); + mantissa = FREXP (x, &exp); + ASSERT (exp == 0); + ASSERT (mantissa == x); + ASSERT (!signbit (mantissa)); + } + + { /* Negative zero. */ + int exp = -9999; + DOUBLE mantissa; + x = MINUS_ZERO; + mantissa = FREXP (x, &exp); + ASSERT (exp == 0); + ASSERT (mantissa == x); + ASSERT (signbit (mantissa)); + } + + for (i = 1, x = L_(1.0); i <= MAX_EXP; i++, x *= L_(2.0)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == L_(0.5)); + } + for (i = 1, x = L_(1.0); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == L_(0.5)); + } + for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == L_(0.5)); + } + + for (i = 1, x = - L_(1.0); i <= MAX_EXP; i++, x *= L_(2.0)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == - L_(0.5)); + } + for (i = 1, x = - L_(1.0); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == - L_(0.5)); + } + for (; i >= MIN_EXP - 100 && x < L_(0.0); i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == - L_(0.5)); + } + + for (i = 1, x = L_(1.01); i <= MAX_EXP; i++, x *= L_(2.0)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == L_(0.505)); + } + for (i = 1, x = L_(1.01); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == L_(0.505)); + } + for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa >= L_(0.5)); + ASSERT (mantissa < L_(1.0)); + ASSERT (mantissa == my_ldexp (x, - exp)); + } + + for (i = 1, x = L_(1.73205); i <= MAX_EXP; i++, x *= L_(2.0)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == L_(0.866025)); + } + for (i = 1, x = L_(1.73205); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i); + ASSERT (mantissa == L_(0.866025)); + } + for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5)) + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (exp == i || exp == i + 1); + ASSERT (mantissa >= L_(0.5)); + ASSERT (mantissa < L_(1.0)); + ASSERT (mantissa == my_ldexp (x, - exp)); + } + + /* Randomized tests. */ + for (i = 0; i < SIZEOF (RANDOM); i++) + { + x = L_(20.0) * RANDOM[i] - L_(10.0); /* -10.0 <= x <= 10.0 */ + { + int exp = -9999; + DOUBLE mantissa = FREXP (x, &exp); + ASSERT (x == my_ldexp (mantissa, exp)); + } + } +} |