Fixing Math.pow

The Math.pow implementation relies on libm's pow. However, the ISO C
and ES5.1 standards differ on pow:
  * `x ** NAN` is NAN in ES but `+1 ** y` is 1 in C
  * `+-1 ** +-INF` is NAN in ES but 1 in C

This patch:
  * Modifies the Math.pow implementation to handle the special cases
    instead calling pow.
  * Adds a test case to jerry-test-suite as it did not test
    `Math.pow(1,NaN)`.
  * Fixes jerry-libm's pow, as it was not standard conforming, which
    helped hiding the error in Math.pow.
  * Updates the unit test for libm.

JerryScript-DCO-1.0-Signed-off-by: Akos Kiss akiss@inf.u-szeged.hu
This commit is contained in:
Akos Kiss
2016-08-10 16:24:12 +02:00
parent 8f76bab92e
commit 9d4f7c917f
5 changed files with 41 additions and 6 deletions
@@ -477,7 +477,16 @@ ecma_builtin_math_object_pow (ecma_value_t this_arg, /**< 'this' argument */
ECMA_OP_TO_NUMBER_TRY_CATCH (x, arg1, ret_value);
ECMA_OP_TO_NUMBER_TRY_CATCH (y, arg2, ret_value);
ret_value = ecma_make_number_value (DOUBLE_TO_ECMA_NUMBER_T (pow (x, y)));
if (ecma_number_is_nan (y) ||
(ecma_number_is_infinity (y) && (x == 1.0 || x == -1.0)))
{
/* Handle differences between ES5.1 and ISO C standards for pow. */
ret_value = ecma_make_number_value (ecma_number_make_nan ());
}
else
{
ret_value = ecma_make_number_value (DOUBLE_TO_ECMA_NUMBER_T (pow (x, y)));
}
ECMA_OP_TO_NUMBER_FINALIZE (y);
ECMA_OP_TO_NUMBER_FINALIZE (x);