| // Copyright 2020 The Tint 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 <cstring> |
| |
| #include "src/tint/writer/wgsl/test_helper.h" |
| |
| using namespace tint::number_suffixes; // NOLINT |
| |
| namespace tint::writer::wgsl { |
| namespace { |
| |
| // Makes an IEEE 754 binary32 floating point number with |
| // - 0 sign if sign is 0, 1 otherwise |
| // - 'exponent_bits' is placed in the exponent space. |
| // So, the exponent bias must already be included. |
| f32 MakeF32(uint32_t sign, uint32_t biased_exponent, uint32_t mantissa) { |
| const uint32_t sign_bit = sign ? 0x80000000u : 0u; |
| // The binary32 exponent is 8 bits, just below the sign. |
| const uint32_t exponent_bits = (biased_exponent & 0xffu) << 23; |
| // The mantissa is the bottom 23 bits. |
| const uint32_t mantissa_bits = (mantissa & 0x7fffffu); |
| |
| uint32_t bits = sign_bit | exponent_bits | mantissa_bits; |
| float result = 0.0f; |
| static_assert(sizeof(result) == sizeof(bits), |
| "expected float and uint32_t to be the same size"); |
| std::memcpy(&result, &bits, sizeof(bits)); |
| return f32(result); |
| } |
| |
| // Get the representation of an IEEE 754 binary16 floating point number with |
| // - 0 sign if sign is 0, 1 otherwise |
| // - 'exponent_bits' is placed in the exponent space. |
| // - the exponent bias (15) already be included. |
| f16 MakeF16(uint32_t sign, uint32_t f16_biased_exponent, uint16_t f16_mantissa) { |
| assert((f16_biased_exponent & 0xffffffe0u) == 0); |
| assert((f16_mantissa & 0xfc00u) == 0); |
| |
| const uint32_t sign_bit = sign ? 0x80000000u : 0u; |
| |
| // F16 has a exponent bias of 15, and f32 bias 127. Adding 127-15=112 to the f16-biased exponent |
| // to get f32-biased exponent. |
| uint32_t f32_biased_exponent = (f16_biased_exponent & 0x1fu) + 112; |
| assert((f32_biased_exponent & 0xffffff00u) == 0); |
| |
| if (f16_biased_exponent == 0) { |
| // +/- zero, or subnormal |
| if (f16_mantissa == 0) { |
| // +/- zero |
| return sign ? f16(-0.0f) : f16(0.0f); |
| } |
| // Subnormal f16, calc the corresponding exponent and mantissa of normal f32. |
| f32_biased_exponent += 1; |
| // There must be at least one of the 10 mantissa bits being 1, left-shift the mantissa bits |
| // until the most significant 1 bit is left-shifted to 10th bit (count from zero), which |
| // will be omitted in the resulting f32 mantissa part. |
| assert(f16_mantissa & 0x03ffu); |
| while ((f16_mantissa & 0x0400u) == 0) { |
| f16_mantissa = static_cast<uint16_t>(f16_mantissa << 1); |
| f32_biased_exponent--; |
| } |
| } |
| |
| // The binary32 exponent is 8 bits, just below the sign. |
| const uint32_t f32_exponent_bits = (f32_biased_exponent & 0xffu) << 23; |
| // The mantissa is the bottom 23 bits. |
| const uint32_t f32_mantissa_bits = (f16_mantissa & 0x03ffu) << 13; |
| |
| uint32_t bits = sign_bit | f32_exponent_bits | f32_mantissa_bits; |
| float result = 0.0f; |
| static_assert(sizeof(result) == sizeof(bits), |
| "expected float and uint32_t to be the same size"); |
| std::memcpy(&result, &bits, sizeof(bits)); |
| return f16(result); |
| } |
| |
| struct F32Data { |
| f32 value; |
| std::string expected; |
| }; |
| |
| struct F16Data { |
| f16 value; |
| std::string expected; |
| }; |
| |
| inline std::ostream& operator<<(std::ostream& out, F32Data data) { |
| out << "{" << data.value << "," << data.expected << "}"; |
| return out; |
| } |
| |
| inline std::ostream& operator<<(std::ostream& out, F16Data data) { |
| out << "{" << data.value << "," << data.expected << "}"; |
| return out; |
| } |
| |
| using WgslGenerator_F32LiteralTest = TestParamHelper<F32Data>; |
| |
| TEST_P(WgslGenerator_F32LiteralTest, Emit) { |
| auto* v = Expr(GetParam().value); |
| |
| SetResolveOnBuild(false); |
| GeneratorImpl& gen = Build(); |
| |
| std::stringstream out; |
| ASSERT_TRUE(gen.EmitLiteral(out, v)) << gen.error(); |
| EXPECT_EQ(out.str(), GetParam().expected); |
| } |
| |
| INSTANTIATE_TEST_SUITE_P(Zero, |
| WgslGenerator_F32LiteralTest, |
| ::testing::ValuesIn(std::vector<F32Data>{{0_f, "0.0f"}, |
| {MakeF32(0, 0, 0), "0.0f"}, |
| {MakeF32(1, 0, 0), "-0.0f"}})); |
| |
| INSTANTIATE_TEST_SUITE_P(Normal, |
| WgslGenerator_F32LiteralTest, |
| ::testing::ValuesIn(std::vector<F32Data>{{1_f, "1.0f"}, |
| {-1_f, "-1.0f"}, |
| {101.375_f, "101.375f"}})); |
| |
| INSTANTIATE_TEST_SUITE_P(Subnormal, |
| WgslGenerator_F32LiteralTest, |
| ::testing::ValuesIn(std::vector<F32Data>{ |
| {MakeF32(0, 0, 1), "0x1p-149f"}, // Smallest |
| {MakeF32(1, 0, 1), "-0x1p-149f"}, |
| {MakeF32(0, 0, 2), "0x1p-148f"}, |
| {MakeF32(1, 0, 2), "-0x1p-148f"}, |
| {MakeF32(0, 0, 0x7fffff), "0x1.fffffcp-127f"}, // Largest |
| {MakeF32(1, 0, 0x7fffff), "-0x1.fffffcp-127f"}, // Largest |
| {MakeF32(0, 0, 0xcafebe), "0x1.2bfaf8p-127f"}, // Scattered bits |
| {MakeF32(1, 0, 0xcafebe), "-0x1.2bfaf8p-127f"}, // Scattered bits |
| {MakeF32(0, 0, 0xaaaaa), "0x1.55554p-130f"}, // Scattered bits |
| {MakeF32(1, 0, 0xaaaaa), "-0x1.55554p-130f"}, // Scattered bits |
| })); |
| |
| INSTANTIATE_TEST_SUITE_P(Infinity, |
| WgslGenerator_F32LiteralTest, |
| ::testing::ValuesIn(std::vector<F32Data>{ |
| {MakeF32(0, 255, 0), "0x1p+128f"}, |
| {MakeF32(1, 255, 0), "-0x1p+128f"}})); |
| |
| using WgslGenerator_F16LiteralTest = TestParamHelper<F16Data>; |
| |
| TEST_P(WgslGenerator_F16LiteralTest, Emit) { |
| Enable(builtin::Extension::kF16); |
| |
| auto* v = Expr(GetParam().value); |
| |
| SetResolveOnBuild(false); |
| GeneratorImpl& gen = Build(); |
| |
| std::stringstream out; |
| ASSERT_TRUE(gen.EmitLiteral(out, v)) << gen.error(); |
| EXPECT_EQ(out.str(), GetParam().expected); |
| } |
| |
| INSTANTIATE_TEST_SUITE_P(Zero, |
| WgslGenerator_F16LiteralTest, |
| ::testing::ValuesIn(std::vector<F16Data>{{0_h, "0.0h"}, |
| {MakeF16(0, 0, 0), "0.0h"}, |
| {MakeF16(1, 0, 0), "-0.0h"}})); |
| |
| INSTANTIATE_TEST_SUITE_P(Normal, |
| WgslGenerator_F16LiteralTest, |
| ::testing::ValuesIn(std::vector<F16Data>{{1_h, "1.0h"}, |
| {-1_h, "-1.0h"}, |
| {101.375_h, "101.375h"}})); |
| |
| INSTANTIATE_TEST_SUITE_P(Subnormal, |
| WgslGenerator_F16LiteralTest, |
| ::testing::ValuesIn(std::vector<F16Data>{ |
| {MakeF16(0, 0, 1), "5.96046448e-08h"}, // Smallest |
| {MakeF16(1, 0, 1), "-5.96046448e-08h"}, |
| {MakeF16(0, 0, 2), "1.1920929e-07h"}, |
| {MakeF16(1, 0, 2), "-1.1920929e-07h"}, |
| {MakeF16(0, 0, 0x3ffu), "6.09755516e-05h"}, // Largest |
| {MakeF16(1, 0, 0x3ffu), "-6.09755516e-05h"}, // Largest |
| {MakeF16(0, 0, 0x3afu), "5.620718e-05h"}, // Scattered bits |
| {MakeF16(1, 0, 0x3afu), "-5.620718e-05h"}, // Scattered bits |
| {MakeF16(0, 0, 0x2c7u), "4.23789024e-05h"}, // Scattered bits |
| {MakeF16(1, 0, 0x2c7u), "-4.23789024e-05h"}, // Scattered bits |
| })); |
| |
| } // namespace |
| } // namespace tint::writer::wgsl |
