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lossless_neon: enable subtract green for aarch64

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similar to:
1ba61b0 enable NEON intrinsics in aarch64 builds

vtbl1_u8 is available everywhere but Xcode-based iOS arm64 builds, use
vtbl1q_u8 there.

performance varies based on the input, 1-3% on encode was observed

(cherry picked from commit 416e1cea9b)

Change-Id: Ifec35b37eb856acfcf69ed7f16fa078cd40b7034
This commit is contained in:
James Zern 2015-01-31 09:47:15 -08:00
parent 5a0c2207f4
commit 0339fa26eb
1 changed files with 36 additions and 12 deletions
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48
src/dsp/lossless_neon.c
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@ -259,20 +259,44 @@ static uint32_t Predictor13(uint32_t left, const uint32_t* const top) {
//------------------------------------------------------------------------------
// Subtract-Green Transform
// vtbl? are unavailable in iOS/arm64 builds.
#if !defined(__aarch64__)
// vtbl?_u8 are marked unavailable for iOS arm64, use wider versions there.
#if defined(__APPLE__) && defined(__aarch64__) && \
defined(__apple_build_version__)
#define USE_VTBLQ
#endif
// 255 = byte will be zero'd
#ifdef USE_VTBLQ
// 255 = byte will be zeroed
static const uint8_t kGreenShuffle[16] = {
1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13, 255
};
static WEBP_INLINE uint8x16_t DoGreenShuffle(const uint8x16_t argb,
const uint8x16_t shuffle) {
return vcombine_u8(vtbl1q_u8(argb, vget_low_u8(shuffle)),
vtbl1q_u8(argb, vget_high_u8(shuffle)));
}
#else // !USE_VTBLQ
// 255 = byte will be zeroed
static const uint8_t kGreenShuffle[8] = { 1, 255, 1, 255, 5, 255, 5, 255 };
static WEBP_INLINE uint8x16_t DoGreenShuffle(const uint8x16_t argb,
const uint8x8_t shuffle) {
return vcombine_u8(vtbl1_u8(vget_low_u8(argb), shuffle),
vtbl1_u8(vget_high_u8(argb), shuffle));
}
#endif // USE_VTBLQ
static void SubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixels) {
const uint32_t* const end = argb_data + (num_pixels & ~3);
#ifdef USE_VTBLQ
const uint8x16_t shuffle = vld1q_u8(kGreenShuffle);
#else
const uint8x8_t shuffle = vld1_u8(kGreenShuffle);
#endif
for (; argb_data < end; argb_data += 4) {
const uint8x16_t argb = vld1q_u8((uint8_t*)argb_data);
const uint8x16_t greens =
vcombine_u8(vtbl1_u8(vget_low_u8(argb), shuffle),
vtbl1_u8(vget_high_u8(argb), shuffle));
const uint8x16_t greens = DoGreenShuffle(argb, shuffle);
vst1q_u8((uint8_t*)argb_data, vsubq_u8(argb, greens));
}
// fallthrough and finish off with plain-C
@ -281,19 +305,21 @@ static void SubtractGreenFromBlueAndRed(uint32_t* argb_data, int num_pixels) {
static void AddGreenToBlueAndRed(uint32_t* argb_data, int num_pixels) {
const uint32_t* const end = argb_data + (num_pixels & ~3);
#ifdef USE_VTBLQ
const uint8x16_t shuffle = vld1q_u8(kGreenShuffle);
#else
const uint8x8_t shuffle = vld1_u8(kGreenShuffle);
#endif
for (; argb_data < end; argb_data += 4) {
const uint8x16_t argb = vld1q_u8((uint8_t*)argb_data);
const uint8x16_t greens =
vcombine_u8(vtbl1_u8(vget_low_u8(argb), shuffle),
vtbl1_u8(vget_high_u8(argb), shuffle));
const uint8x16_t greens = DoGreenShuffle(argb, shuffle);
vst1q_u8((uint8_t*)argb_data, vaddq_u8(argb, greens));
}
// fallthrough and finish off with plain-C
VP8LAddGreenToBlueAndRed_C(argb_data, num_pixels & 3);
}
#endif // !__aarch64__
#undef USE_VTBLQ
#endif // USE_INTRINSICS
@ -320,11 +346,9 @@ void VP8LDspInitNEON(void) {
VP8LPredictors[12] = Predictor12;
VP8LPredictors[13] = Predictor13;
#if !defined(__aarch64__)
VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed;
VP8LAddGreenToBlueAndRed = AddGreenToBlueAndRed;
#endif
#endif
#endif // WEBP_USE_NEON
}