mirror of
https://github.com/jerryscript-project/jerryscript.git
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63 lines
2.4 KiB
C++
63 lines
2.4 KiB
C++
/* Copyright 2014-2015 Samsung Electronics Co., Ltd.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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#include "jrt.h"
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#include "jrt-bit-fields.h"
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/**
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* Extract a bit-field from the integer.
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*
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* @return bit-field's value
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*/
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uint64_t __attr_const___
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jrt_extract_bit_field (uint64_t container, /**< container to extract bit-field from */
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uint32_t lsb, /**< least significant bit of the value
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* to be extracted */
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uint32_t width) /**< width of the bit-field to be extracted */
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{
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JERRY_ASSERT (lsb < JERRY_BITSINBYTE * sizeof (uint64_t));
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JERRY_ASSERT (width < JERRY_BITSINBYTE * sizeof (uint64_t));
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JERRY_ASSERT ((lsb + width) <= JERRY_BITSINBYTE * sizeof (uint64_t));
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uint64_t shifted_value = container >> lsb;
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uint64_t bit_field_mask = (1ull << width) - 1;
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return (shifted_value & bit_field_mask);
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} /* jrt_extract_bit_field */
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/**
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* Extract a bit-field from the integer.
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*
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* @return bit-field's value
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*/
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uint64_t __attr_const___
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jrt_set_bit_field_value (uint64_t container, /**< container to insert bit-field to */
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uint64_t new_bit_field_value, /**< value of bit-field to insert */
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uint32_t lsb, /**< least significant bit of the value
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* to be extracted */
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uint32_t width) /**< width of the bit-field to be extracted */
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{
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JERRY_ASSERT (lsb < JERRY_BITSINBYTE * sizeof (uint64_t));
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JERRY_ASSERT (width < JERRY_BITSINBYTE * sizeof (uint64_t));
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JERRY_ASSERT ((lsb + width) <= JERRY_BITSINBYTE * sizeof (uint64_t));
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JERRY_ASSERT (new_bit_field_value < (1ull << width));
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uint64_t bit_field_mask = (1ull << width) - 1;
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uint64_t shifted_bit_field_mask = bit_field_mask << lsb;
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uint64_t shifted_new_bit_field_value = new_bit_field_value << lsb;
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return (container & ~shifted_bit_field_mask) | shifted_new_bit_field_value;
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} /* jrt_set_bit_field_value */
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