| // Copyright 2017 The Dawn Authors |
| // |
| // Licensed under the Apache License, Version 2.0 (the "License"); |
| // you may not use this file except in compliance with the License. |
| // You may obtain a copy of the License at |
| // |
| // http://www.apache.org/licenses/LICENSE-2.0 |
| // |
| // Unless required by applicable law or agreed to in writing, software |
| // distributed under the License is distributed on an "AS IS" BASIS, |
| // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| // See the License for the specific language governing permissions and |
| // limitations under the License. |
| |
| #include "common/Math.h" |
| |
| #include "common/Assert.h" |
| #include "common/Platform.h" |
| |
| #include <algorithm> |
| #include <cmath> |
| #include <limits> |
| |
| #if defined(DAWN_COMPILER_MSVC) |
| # include <intrin.h> |
| #endif |
| |
| uint32_t ScanForward(uint32_t bits) { |
| ASSERT(bits != 0); |
| #if defined(DAWN_COMPILER_MSVC) |
| unsigned long firstBitIndex = 0ul; |
| unsigned char ret = _BitScanForward(&firstBitIndex, bits); |
| ASSERT(ret != 0); |
| return firstBitIndex; |
| #else |
| return static_cast<uint32_t>(__builtin_ctz(bits)); |
| #endif |
| } |
| |
| uint32_t Log2(uint32_t value) { |
| ASSERT(value != 0); |
| #if defined(DAWN_COMPILER_MSVC) |
| unsigned long firstBitIndex = 0ul; |
| unsigned char ret = _BitScanReverse(&firstBitIndex, value); |
| ASSERT(ret != 0); |
| return firstBitIndex; |
| #else |
| return 31 - static_cast<uint32_t>(__builtin_clz(value)); |
| #endif |
| } |
| |
| uint32_t Log2(uint64_t value) { |
| ASSERT(value != 0); |
| #if defined(DAWN_COMPILER_MSVC) |
| # if defined(DAWN_PLATFORM_64_BIT) |
| unsigned long firstBitIndex = 0ul; |
| unsigned char ret = _BitScanReverse64(&firstBitIndex, value); |
| ASSERT(ret != 0); |
| return firstBitIndex; |
| # else // defined(DAWN_PLATFORM_64_BIT) |
| unsigned long firstBitIndex = 0ul; |
| if (_BitScanReverse(&firstBitIndex, value >> 32)) { |
| return firstBitIndex + 32; |
| } |
| unsigned char ret = _BitScanReverse(&firstBitIndex, value & 0xFFFFFFFF); |
| ASSERT(ret != 0); |
| return firstBitIndex; |
| # endif // defined(DAWN_PLATFORM_64_BIT) |
| #else // defined(DAWN_COMPILER_MSVC) |
| return 63 - static_cast<uint32_t>(__builtin_clzll(value)); |
| #endif // defined(DAWN_COMPILER_MSVC) |
| } |
| |
| uint64_t NextPowerOfTwo(uint64_t n) { |
| if (n <= 1) { |
| return 1; |
| } |
| |
| return 1ull << (Log2(n - 1) + 1); |
| } |
| |
| bool IsPowerOfTwo(uint64_t n) { |
| ASSERT(n != 0); |
| return (n & (n - 1)) == 0; |
| } |
| |
| bool IsPtrAligned(const void* ptr, size_t alignment) { |
| ASSERT(IsPowerOfTwo(alignment)); |
| ASSERT(alignment != 0); |
| return (reinterpret_cast<size_t>(ptr) & (alignment - 1)) == 0; |
| } |
| |
| bool IsAligned(uint32_t value, size_t alignment) { |
| ASSERT(alignment <= UINT32_MAX); |
| ASSERT(IsPowerOfTwo(alignment)); |
| ASSERT(alignment != 0); |
| uint32_t alignment32 = static_cast<uint32_t>(alignment); |
| return (value & (alignment32 - 1)) == 0; |
| } |
| |
| uint16_t Float32ToFloat16(float fp32) { |
| uint32_t fp32i = BitCast<uint32_t>(fp32); |
| uint32_t sign16 = (fp32i & 0x80000000) >> 16; |
| uint32_t mantissaAndExponent = fp32i & 0x7FFFFFFF; |
| |
| if (mantissaAndExponent > 0x7F800000) { // NaN |
| return 0x7FFF; |
| } else if (mantissaAndExponent > 0x47FFEFFF) { // Infinity |
| return static_cast<uint16_t>(sign16 | 0x7C00); |
| } else if (mantissaAndExponent < 0x38800000) { // Denormal |
| uint32_t mantissa = (mantissaAndExponent & 0x007FFFFF) | 0x00800000; |
| int32_t exponent = 113 - (mantissaAndExponent >> 23); |
| |
| if (exponent < 24) { |
| mantissaAndExponent = mantissa >> exponent; |
| } else { |
| mantissaAndExponent = 0; |
| } |
| |
| return static_cast<uint16_t>( |
| sign16 | (mantissaAndExponent + 0x00000FFF + ((mantissaAndExponent >> 13) & 1)) >> 13); |
| } else { |
| return static_cast<uint16_t>(sign16 | (mantissaAndExponent + 0xC8000000 + 0x00000FFF + |
| ((mantissaAndExponent >> 13) & 1)) >> |
| 13); |
| } |
| } |
| |
| bool IsFloat16NaN(uint16_t fp16) { |
| return (fp16 & 0x7FFF) > 0x7C00; |
| } |
| |
| // Based on the Khronos Data Format Specification 1.2 Section 13.3 sRGB transfer functions |
| float SRGBToLinear(float srgb) { |
| // sRGB is always used in unsigned normalized formats so clamp to [0.0, 1.0] |
| if (srgb <= 0.0f) { |
| return 0.0f; |
| } else if (srgb > 1.0f) { |
| return 1.0f; |
| } |
| |
| if (srgb < 0.04045f) { |
| return srgb / 12.92f; |
| } else { |
| return std::pow((srgb + 0.055f) / 1.055f, 2.4f); |
| } |
| } |
| |
| uint64_t RoundUp(uint64_t n, uint64_t m) { |
| ASSERT(m > 0); |
| ASSERT(n > 0); |
| ASSERT(m <= std::numeric_limits<uint64_t>::max() - n); |
| return ((n + m - 1) / m) * m; |
| } |