mirror of
https://github.com/encounter/dawn-cmake.git
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80 lines
2.4 KiB
C++
80 lines
2.4 KiB
C++
// Copyright 2017 The NXT Authors
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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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#include "common/Math.h"
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#include "common/Assert.h"
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#if defined(NXT_COMPILER_MSVC)
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# include <intrin.h>
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#endif
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uint32_t ScanForward(uint32_t bits) {
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ASSERT(bits != 0);
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#if defined(NXT_COMPILER_MSVC)
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unsigned long firstBitIndex = 0ul;
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unsigned char ret = _BitScanForward(&firstBitIndex, bits);
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ASSERT(ret != 0);
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return firstBitIndex;
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#else
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return static_cast<uint32_t>(__builtin_ctz(bits));
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#endif
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}
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uint32_t Log2(uint32_t value) {
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ASSERT(value != 0);
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#if defined(NXT_COMPILER_MSVC)
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unsigned long firstBitIndex = 0ul;
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unsigned char ret = _BitScanReverse(&firstBitIndex, value);
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ASSERT(ret != 0);
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return firstBitIndex;
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#else
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return 31 - static_cast<uint32_t>(__builtin_clz(value));
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#endif
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}
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bool IsPowerOfTwo(size_t n) {
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ASSERT(n != 0);
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return (n & (n - 1)) == 0;
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}
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bool IsPtrAligned(const void* ptr, size_t alignment) {
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ASSERT(IsPowerOfTwo(alignment));
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ASSERT(alignment != 0);
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return (reinterpret_cast<size_t>(ptr) & (alignment - 1)) == 0;
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}
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void* AlignVoidPtr(void* ptr, size_t alignment) {
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ASSERT(IsPowerOfTwo(alignment));
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ASSERT(alignment != 0);
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return reinterpret_cast<void*>((reinterpret_cast<size_t>(ptr) + (alignment - 1)) &
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~(alignment - 1));
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}
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bool IsAligned(uint32_t value, size_t alignment) {
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ASSERT(alignment <= UINT32_MAX);
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ASSERT(IsPowerOfTwo(alignment));
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ASSERT(alignment != 0);
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uint32_t alignment32 = static_cast<uint32_t>(alignment);
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return (value & (alignment32 - 1)) == 0;
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}
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uint32_t Align(uint32_t value, size_t alignment) {
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ASSERT(alignment <= UINT32_MAX);
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ASSERT(IsPowerOfTwo(alignment));
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ASSERT(alignment != 0);
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uint32_t alignment32 = static_cast<uint32_t>(alignment);
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return (value + (alignment32 - 1)) & ~(alignment32 - 1);
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}
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