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Improve multiplication in vm

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This patch improves the ecma_integers_values multiplication by checking if the multiplier or multiplicand is power of 2.
If it is it uses right shift instead of multiplication.

JerryScript-DCO-1.0-Signed-off-by: Robert Fancsik frobert@inf.u-szeged.hu
This commit is contained in:
Robert Fancsik
2017-11-27 12:56:50 +01:00
committed by yichoi
parent 90f2473f08
commit 458dc58b59
3 changed files with 27 additions and 1 deletions
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jerry-core/ecma/base/ecma-helpers-number.c
+25
View File
@@ -653,6 +653,31 @@ ecma_number_calc_remainder (ecma_number_t left_num, /**< left operand */
return r;
} /* ecma_number_calc_remainder */
/**
* ECMA-integer number multiplication.
*
* @return number - result of multiplication.
*/
inline ecma_value_t __attr_always_inline___
ecma_integer_multiply (ecma_integer_value_t left_integer, /**< left operand */
ecma_integer_value_t right_integer) /**< right operand */
{
#if defined (__GNUC__) || defined (__clang__)
/* Check if left_integer is power of 2 */
if (unlikely ((left_integer & (left_integer - 1)) == 0))
{
/* Right shift right_integer with log2 (left_integer) */
return ecma_make_integer_value (right_integer << (__builtin_ctz ((unsigned int) left_integer)));
}
else if (unlikely ((right_integer & (right_integer - 1)) == 0))
{
/* Right shift left_integer with log2 (right_integer) */
return ecma_make_integer_value (left_integer << (__builtin_ctz ((unsigned int) right_integer)));
}
#endif /* defined (__GNUC__) || defined (__clang__) */
return ecma_make_integer_value (left_integer * right_integer);
} /* ecma_integer_multiply */
/**
* @}
* @}
jerry-core/ecma/base/ecma-helpers.h
+1
View File
@@ -243,6 +243,7 @@ ecma_number_t ecma_number_get_prev (ecma_number_t num);
ecma_number_t ecma_number_get_next (ecma_number_t num);
ecma_number_t ecma_number_trunc (ecma_number_t num);
ecma_number_t ecma_number_calc_remainder (ecma_number_t left_num, ecma_number_t right_num);
ecma_value_t ecma_integer_multiply (ecma_integer_value_t left_integer, ecma_integer_value_t right_integer);
lit_utf8_size_t ecma_number_to_decimal (ecma_number_t num, lit_utf8_byte_t *out_digits_p, int32_t *out_decimal_exp_p);
lit_utf8_size_t ecma_number_to_binary_floating_point_number (ecma_number_t num,
lit_utf8_byte_t *out_digits_p,
jerry-core/vm/vm.c
+1 -1
View File
@@ -1793,7 +1793,7 @@ vm_loop (vm_frame_ctx_t *frame_ctx_p) /**< frame context */
&& left_value != 0
&& right_value != 0)
{
result = ecma_make_integer_value (left_integer * right_integer);
result = ecma_integer_multiply (left_integer, right_integer);
break;
}