static bool eq_within_half_float(float a, float b) {
const float kTolerance = 1.0f / (1 << (8 + 10));
SkHalf ha = SkFloatToHalf(a);
SkHalf hb = SkFloatToHalf(b);
float a2 = SkHalfToFloat(ha);
float b2 = SkHalfToFloat(hb);
return fabsf(a2 - b2) <= kTolerance;
}
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 = signbit(f) ? 0x8000 : 0x0000;
}
uint16_t actual = SkFloatToHalf_finite_ftz(Sk4f{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);
}
}
DEF_TEST(FloatToHalf_finite, 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);
if (isfinite(f) && isfinite(SkHalfToFloat(SkFloatToHalf(f)))) {
uint16_t h1 = SkFloatToHalf_finite(Sk4f(f,0,0,0))[0],
h2 = SkFloatToHalf(f);
bool ok = (h1 == h2 || h1 == h2-1);
REPORTER_ASSERT(r, ok);
if (!ok) {
SkDebugf("%08x (%g) -> %04x, want %04x (%g)\n",
bits, f, h1, h2, SkHalfToFloat(h2));
break;
}
}
}
}
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;
}
}
}
void SkPM4f::toF16(uint16_t half[4]) const {
for (int i = 0; i < 4; ++i) {
half[i] = SkFloatToHalf(fVec[i]);
}
}
static void float_to_half(uint16_t dst[], const float src[], int n) {
while (n-->0) {
*dst++ = SkFloatToHalf(*src++);
}
}
