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Improve ECMA_PROPERTY_VALUE_PTR computation. (#1364)

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JerryScript-DCO-1.0-Signed-off-by: Zoltan Herczeg zherczeg.u-szeged@partner.samsung.com
This commit is contained in:
zherczeg
2016-09-20 12:50:53 +02:00
committed by GitHub
parent 971dcae669
commit 9ab72d24b7
1 changed files with 12 additions and 18 deletions
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jerry-core/ecma/base/ecma-globals.h
+12 -18
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@@ -332,17 +332,10 @@ typedef enum
* a packed struct would only consume sizeof(ecma_value_t)+1 memory * a packed struct would only consume sizeof(ecma_value_t)+1 memory
* bytes, accessing such structure is inefficient from the CPU viewpoint * bytes, accessing such structure is inefficient from the CPU viewpoint
* because the value is not naturally aligned. To improve performance, * because the value is not naturally aligned. To improve performance,
* multiple type bytes and values are packed together. The maximum * two type bytes and values are packed together. The memory layout is
* number of packed items is sizeof(ecma_value_t). The memory layout is * the following:
* the following when the maximum number of items is present:
* *
* [type 1, type 2, type 3, type 4][value 1][value 2][value 3][value 4] * [type 1, type 2, unused byte 1, unused byte 2][value 1][value 2]
*
* This way no memory is wasted and values are naturally aligned.
*
* For property pairs, only two values are used:
*
* [type 1, type 2, unused 1, unused 2][value 1][value 2]
* *
* The unused two bytes are used to store a compressed pointer for the * The unused two bytes are used to store a compressed pointer for the
* next property pair. * next property pair.
@@ -426,22 +419,23 @@ typedef struct
((ecma_internal_property_id_t) (*(property_p) >> ECMA_PROPERTY_FLAG_SHIFT)) ((ecma_internal_property_id_t) (*(property_p) >> ECMA_PROPERTY_FLAG_SHIFT))
/** /**
* Computing the data offset of a property. * Add the offset part to a property for computing its property data pointer.
*/ */
#define ECMA_PROPERTY_VALUE_OFFSET(property_p) \ #define ECMA_PROPERTY_VALUE_ADD_OFFSET(property_p) \
((((uintptr_t) (property_p)) & (sizeof (ecma_property_value_t) - 1)) + 1) ((uintptr_t) ((((uint8_t *) (property_p)) + (sizeof (ecma_property_value_t) * 2 - 1))))
/** /**
* Computing the base address of property data list. * Align the property for computing its property data pointer.
*/ */
#define ECMA_PROPERTY_VALUE_BASE_PTR(property_p) \ #define ECMA_PROPERTY_VALUE_DATA_PTR(property_p) \
((ecma_property_value_t *) (((uintptr_t) (property_p)) & ~(sizeof (ecma_property_value_t) - 1))) (ECMA_PROPERTY_VALUE_ADD_OFFSET (property_p) & ~(sizeof (ecma_property_value_t) - 1))
/** /**
* Pointer to property data. * Compute the property data pointer of a property.
* The property must be part of a property pair.
*/ */
#define ECMA_PROPERTY_VALUE_PTR(property_p) \ #define ECMA_PROPERTY_VALUE_PTR(property_p) \
(ECMA_PROPERTY_VALUE_BASE_PTR (property_p) + ECMA_PROPERTY_VALUE_OFFSET (property_p)) ((ecma_property_value_t *) ECMA_PROPERTY_VALUE_DATA_PTR (property_p))
/** /**
* Property reference. * Property reference.