- 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 = NaN ();
- mantissa = frexp (x, &exp);
- ASSERT (isnan (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);
- ASSERT (!signbit (mantissa));
- }
-
- { /* Negative zero. */
- int exp = -9999;
- double mantissa;
- x = -0.0;
- mantissa = frexp (x, &exp);
- ASSERT (exp == 0);
- ASSERT (mantissa == x);
- ASSERT (signbit (mantissa));
- }
-
- 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));
- }