| /* |
| * Copyright 2016 Google Inc. |
| * |
| * Use of this source code is governed by a BSD-style license that can be |
| * found in the LICENSE file. |
| */ |
| |
| #include "src/base/SkHalf.h" |
| #include "src/base/SkRandom.h" |
| #include "src/base/SkVx.h" |
| #include "tests/Test.h" |
| |
| #include <cmath> |
| #include <cstdint> |
| #include <cstring> |
| |
| static bool is_denorm(uint16_t h) { |
| return (h & 0x7fff) < 0x0400; |
| } |
| |
| static bool is_finite(uint16_t h) { |
| return (h & 0x7c00) != 0x7c00; |
| } |
| |
| DEF_TEST(SkHalfToFloat_finite_ftz, r) { |
| for (uint32_t h = 0; h <= 0xffff; h++) { |
| if (!is_finite(h)) { |
| // _finite_ftz() only works for values that can be represented as a finite half float. |
| continue; |
| } |
| |
| // _finite_ftz() may flush denorms to zero. 0.0f will compare == with both +0.0f and -0.0f. |
| float expected = SkHalfToFloat(h), |
| alternate = is_denorm(h) ? 0.0f : expected; |
| |
| float actual = SkHalfToFloat_finite_ftz(h)[0]; |
| |
| REPORTER_ASSERT(r, actual == expected || actual == alternate); |
| } |
| } |
| |
| DEF_TEST(SkFloatToHalf_finite_ftz, r) { |
| #if 0 |
| for (uint64_t bits = 0; bits <= 0xffffffff; bits++) { |
| #else |
| SkRandom rand; |
| for (int i = 0; i < 1000000; i++) { |
| uint32_t bits = rand.nextU(); |
| #endif |
| float f; |
| memcpy(&f, &bits, 4); |
| |
| uint16_t expected = SkFloatToHalf(f); |
| if (!is_finite(expected)) { |
| // _finite_ftz() only works for values that can be represented as a finite half float. |
| continue; |
| } |
| |
| uint16_t alternate = expected; |
| if (is_denorm(expected)) { |
| // _finite_ftz() may flush denorms to zero, and happens to keep the sign bit. |
| alternate = std::signbit(f) ? 0x8000 : 0x0000; |
| } |
| |
| uint16_t actual = SkFloatToHalf_finite_ftz(skvx::float4{f})[0]; |
| // _finite_ftz() may truncate instead of rounding, so it may be one too small. |
| REPORTER_ASSERT(r, actual == expected || actual == expected - 1 || |
| actual == alternate || actual == alternate - 1); |
| } |
| } |