1 /* 2 * Copyright 2016 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #include "SkAutoPixmapStorage.h" 9 #include "SkColor.h" 10 #include "SkHalf.h" 11 #include "SkOpts.h" 12 #include "SkPixmap.h" 13 #include "SkRandom.h" 14 #include "SkTo.h" 15 #include "Test.h" 16 17 #include <cmath> 18 19 static bool is_denorm(uint16_t h) { 20 return (h & 0x7fff) < 0x0400; 21 } 22 23 static bool is_finite(uint16_t h) { 24 return (h & 0x7c00) != 0x7c00; 25 } 26 27 DEF_TEST(SkHalfToFloat_finite_ftz, r) { 28 for (uint32_t h = 0; h <= 0xffff; h++) { 29 if (!is_finite(h)) { 30 // _finite_ftz() only works for values that can be represented as a finite half float. 31 continue; 32 } 33 34 // _finite_ftz() may flush denorms to zero. 0.0f will compare == with both +0.0f and -0.0f. 35 float expected = SkHalfToFloat(h), 36 alternate = is_denorm(h) ? 0.0f : expected; 37 38 float actual = SkHalfToFloat_finite_ftz(h)[0]; 39 40 REPORTER_ASSERT(r, actual == expected || actual == alternate); 41 } 42 } 43 44 DEF_TEST(SkFloatToHalf_finite_ftz, r) { 45 #if 0 46 for (uint64_t bits = 0; bits <= 0xffffffff; bits++) { 47 #else 48 SkRandom rand; 49 for (int i = 0; i < 1000000; i++) { 50 uint32_t bits = rand.nextU(); 51 #endif 52 float f; 53 memcpy(&f, &bits, 4); 54 55 uint16_t expected = SkFloatToHalf(f); 56 if (!is_finite(expected)) { 57 // _finite_ftz() only works for values that can be represented as a finite half float. 58 continue; 59 } 60 61 uint16_t alternate = expected; 62 if (is_denorm(expected)) { 63 // _finite_ftz() may flush denorms to zero, and happens to keep the sign bit. 64 alternate = std::signbit(f) ? 0x8000 : 0x0000; 65 } 66 67 uint16_t actual = SkFloatToHalf_finite_ftz(Sk4f{f})[0]; 68 // _finite_ftz() may truncate instead of rounding, so it may be one too small. 69 REPORTER_ASSERT(r, actual == expected || actual == expected - 1 || 70 actual == alternate || actual == alternate - 1); 71 } 72 } 73
