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/* Test of logb*() function family.
Copyright (C) 2012-2023 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;
DOUBLE y;
/* Some particular values. */
x = L_(0.6);
y = LOGB (x);
ASSERT (y == - L_(1.0));
x = L_(1.2);
y = LOGB (x);
ASSERT (y == L_(0.0));
x = L_(2.1);
y = LOGB (x);
ASSERT (y == L_(1.0));
x = L_(3.9);
y = LOGB (x);
ASSERT (y == L_(1.0));
x = L_(4.0);
y = LOGB (x);
ASSERT (y == (FLT_RADIX == 2 ? L_(2.0) : L_(1.0)));
x = L_(0.25);
y = LOGB (x);
ASSERT (y == (FLT_RADIX == 2 ? - L_(2.0) : - L_(1.0)));
/* Zero. */
ASSERT (LOGB (L_(0.0)) == - HUGEVAL);
ASSERT (LOGB (MINUS_ZERO) == - HUGEVAL);
/* From here on, this test assumes FLT_RADIX == 2. */
for (i = 1, x = L_(1.0); i <= MAX_EXP; i++, x *= L_(2.0))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (i = 1, x = L_(1.0); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (i = 1, x = - L_(1.0); i <= MAX_EXP; i++, x *= L_(2.0))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (i = 1, x = - L_(1.0); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (; i >= MIN_EXP - 100 && x < L_(0.0); i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (i = 1, x = L_(1.01); i <= MAX_EXP; i++, x *= L_(2.0))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (i = 1, x = L_(1.01); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (i = 1, x = L_(1.73205); i <= MAX_EXP; i++, x *= L_(2.0))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (i = 1, x = L_(1.73205); i >= MIN_NORMAL_EXP; i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1));
}
for (; i >= MIN_EXP - 100 && x > L_(0.0); i--, x *= L_(0.5))
{
y = LOGB (x);
ASSERT (y == (DOUBLE)(i - 1) || y == (DOUBLE)i);
}
/* Randomized tests. */
for (i = 0; i < SIZEOF (RANDOM); i++)
{
x = L_(20.0) * RANDOM[i] - L_(10.0); /* -10.0 <= x <= 10.0 */
if (x != L_(0.0))
{
DOUBLE abs_x = (x < L_(0.0) ? - x : x);
y = LOGB (x);
ASSERT (y == (DOUBLE) (int) y);
ASSERT (abs_x >= my_ldexp (L_(1.0), (int) y));
ASSERT (abs_x < my_ldexp (L_(1.0), (int) y + 1));
}
}
}
volatile DOUBLE x;
DOUBLE y;
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