| // 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/ast/override_decoration.h" |
| #include "src/writer/wgsl/test_helper.h" |
| |
| namespace tint { |
| namespace writer { |
| namespace 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. |
| float MakeFloat(int sign, int biased_exponent, int 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 result; |
| } |
| |
| struct FloatData { |
| float value; |
| std::string expected; |
| }; |
| inline std::ostream& operator<<(std::ostream& out, FloatData data) { |
| out << "{" << data.value << "," << data.expected << "}"; |
| return out; |
| } |
| |
| using WgslGenerator_FloatLiteralTest = TestParamHelper<FloatData>; |
| |
| TEST_P(WgslGenerator_FloatLiteralTest, 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_FloatLiteralTest, |
| ::testing::ValuesIn(std::vector<FloatData>{ |
| {0.0f, "0.0"}, |
| {MakeFloat(0, 0, 0), "0.0"}, |
| {MakeFloat(1, 0, 0), "-0.0"}})); |
| |
| INSTANTIATE_TEST_SUITE_P(Normal, |
| WgslGenerator_FloatLiteralTest, |
| ::testing::ValuesIn(std::vector<FloatData>{ |
| {1.0f, "1.0"}, |
| {-1.0f, "-1.0"}, |
| {101.375, "101.375"}})); |
| |
| INSTANTIATE_TEST_SUITE_P( |
| Subnormal, |
| WgslGenerator_FloatLiteralTest, |
| ::testing::ValuesIn(std::vector<FloatData>{ |
| {MakeFloat(0, 0, 1), "0x1p-149"}, // Smallest |
| {MakeFloat(1, 0, 1), "-0x1p-149"}, |
| {MakeFloat(0, 0, 2), "0x1p-148"}, |
| {MakeFloat(1, 0, 2), "-0x1p-148"}, |
| {MakeFloat(0, 0, 0x7fffff), "0x1.fffffcp-127"}, // Largest |
| {MakeFloat(1, 0, 0x7fffff), "-0x1.fffffcp-127"}, // Largest |
| {MakeFloat(0, 0, 0xcafebe), "0x1.2bfaf8p-127"}, // Scattered bits |
| {MakeFloat(1, 0, 0xcafebe), "-0x1.2bfaf8p-127"}, // Scattered bits |
| {MakeFloat(0, 0, 0xaaaaa), "0x1.55554p-130"}, // Scattered bits |
| {MakeFloat(1, 0, 0xaaaaa), "-0x1.55554p-130"}, // Scattered bits |
| })); |
| |
| INSTANTIATE_TEST_SUITE_P(Infinity, |
| WgslGenerator_FloatLiteralTest, |
| ::testing::ValuesIn(std::vector<FloatData>{ |
| {MakeFloat(0, 255, 0), "0x1p+128"}, |
| {MakeFloat(1, 255, 0), "-0x1p+128"}})); |
| |
| INSTANTIATE_TEST_SUITE_P( |
| // TODO(dneto): It's unclear how Infinity and NaN should be handled. |
| // https://github.com/gpuweb/gpuweb/issues/1769 |
| // This test fails on Windows x86-64 because the machine sets the high |
| // mantissa bit on NaNs. |
| DISABLED_NaN, |
| // In the NaN case, the top bit in the mantissa is often used to encode |
| // whether the NaN is signalling or quiet, but no agreement between |
| // different machine architectures on whether 1 means signalling or |
| // if 1 means quiet. |
| WgslGenerator_FloatLiteralTest, |
| ::testing::ValuesIn(std::vector<FloatData>{ |
| // LSB only. Smallest mantissa. |
| {MakeFloat(0, 255, 1), "0x1.000002p+128"}, // Smallest mantissa |
| {MakeFloat(1, 255, 1), "-0x1.000002p+128"}, |
| // MSB only. |
| {MakeFloat(0, 255, 0x400000), "0x1.8p+128"}, |
| {MakeFloat(1, 255, 0x400000), "-0x1.8p+128"}, |
| // All 1s in the mantissa. |
| {MakeFloat(0, 255, 0x7fffff), "0x1.fffffep+128"}, |
| {MakeFloat(1, 255, 0x7fffff), "-0x1.fffffep+128"}, |
| // Scattered bits, with 0 in top mantissa bit. |
| {MakeFloat(0, 255, 0x20101f), "0x1.40203ep+128"}, |
| {MakeFloat(1, 255, 0x20101f), "-0x1.40203ep+128"}, |
| // Scattered bits, with 1 in top mantissa bit. |
| {MakeFloat(0, 255, 0x40101f), "0x1.80203ep+128"}, |
| {MakeFloat(1, 255, 0x40101f), "-0x1.80203ep+128"}})); |
| |
| } // namespace |
| } // namespace wgsl |
| } // namespace writer |
| } // namespace tint |