From fff055cc5f9ca5015678f4f13a4f842084bd62d5 Mon Sep 17 00:00:00 2001 From: mtklein Date: Thu, 11 Feb 2016 06:30:03 -0800 Subject: SkHalfToFloat_01 / SkFloatToHalf_01 These are basically inlined, 4-at-a-time versions of our existing functions, but cut down to avoid any work that's only necessary outside [0,1]. Both f16 and f32 denorms should work fine modulo the usual ARMv7 NEON denorm==zero caveat. In exchange for a little speed, f32->f16 does not round properly. Instead it truncates, so it's never off by more than 1 bit. Support for finite values >1 or <0 is straightforward to add back. >1 might already work as-is. Getting close to _u16 performance: micros bench 261.13 xferu64_bw_1_opaque_u16 1833.51 xferu64_bw_1_alpha_u16 2762.32 ? xferu64_aa_1_opaque_u16 3334.29 xferu64_aa_1_alpha_u16 249.78 xferu64_bw_1_opaque_f16 3383.18 xferu64_bw_1_alpha_f16 4214.72 xferu64_aa_1_opaque_f16 4701.19 xferu64_aa_1_alpha_f16 BUG=skia: GOLD_TRYBOT_URL= https://gold.skia.org/search2?unt=true&query=source_type%3Dgm&master=false&issue=1685133005 Committed: https://skia.googlesource.com/skia/+/9ea11a4235b3e3521cc8bf914a27c2d0dc062db9 CQ_EXTRA_TRYBOTS=client.skia:Test-Ubuntu-GCC-GCE-CPU-AVX2-x86_64-Release-SKNX_NO_SIMD-Trybot Review URL: https://codereview.chromium.org/1685133005 --- tests/Float16Test.cpp | 35 +++++++++++++++++++++++++++++++++++ 1 file changed, 35 insertions(+) (limited to 'tests/Float16Test.cpp') diff --git a/tests/Float16Test.cpp b/tests/Float16Test.cpp index f437268c79..f96d904567 100644 --- a/tests/Float16Test.cpp +++ b/tests/Float16Test.cpp @@ -10,6 +10,7 @@ #include "SkHalf.h" #include "SkOpts.h" #include "SkPixmap.h" +#include "SkRandom.h" static bool eq_within_half_float(float a, float b) { const float kTolerance = 1.0f / (1 << (8 + 10)); @@ -64,3 +65,37 @@ DEF_TEST(float_to_half, reporter) { SkOpts::half_to_float(fscratch, hs, 7); REPORTER_ASSERT(reporter, 0 == memcmp(fscratch, fs, sizeof(fs))); } + +DEF_TEST(HalfToFloat_01, r) { + for (uint16_t h = 0; h < 0x8000; h++) { + float f = SkHalfToFloat(h); + if (f >= 0 && f <= 1) { + REPORTER_ASSERT(r, SkHalfToFloat_01(h)[0] == f); + REPORTER_ASSERT(r, SkFloatToHalf_01(SkHalfToFloat_01(h)) == h); + } + } +} + +DEF_TEST(FloatToHalf_01, r) { +#if 0 + for (uint32_t bits = 0; bits < 0x80000000; bits++) { +#else + SkRandom rand; + for (int i = 0; i < 1000000; i++) { + uint32_t bits = rand.nextU(); +#endif + float f; + memcpy(&f, &bits, 4); + if (f >= 0 && f <= 1) { + uint16_t h1 = (uint16_t)SkFloatToHalf_01(Sk4f(f,0,0,0)), + h2 = SkFloatToHalf(f); + bool ok = (h1 == h2 || h1 == h2-1); + REPORTER_ASSERT(r, ok); + if (!ok) { + SkDebugf("%08x (%d) -> %04x (%d), want %04x (%d)\n", + bits, bits>>23, h1, h1>>10, h2, h2>>10); + break; + } + } + } +} -- cgit v1.2.3