godot/thirdparty/libwebp/dsp/lossless_enc_neon.c
Rémi Verschelde ee3cf211c6 webp: Make it a module and unbundle libwebp thirdparty files
Note that there are two Godot-specific changes made to libwebp
for the javascript/HTML5 platform. They are documented in the
README.md.
2016-10-15 11:50:39 +02:00

144 lines
5.0 KiB
C

// Copyright 2015 Google Inc. All Rights Reserved.
//
// Use of this source code is governed by a BSD-style license
// that can be found in the COPYING file in the root of the source
// tree. An additional intellectual property rights grant can be found
// in the file PATENTS. All contributing project authors may
// be found in the AUTHORS file in the root of the source tree.
// -----------------------------------------------------------------------------
//
// NEON variant of methods for lossless encoder
//
// Author: Skal (pascal.massimino@gmail.com)
#include "./dsp.h"
#if defined(WEBP_USE_NEON)
#include <arm_neon.h>
#include "./lossless.h"
#include "./neon.h"
//------------------------------------------------------------------------------
// Subtract-Green Transform
// vtbl?_u8 are marked unavailable for iOS arm64 with Xcode < 6.3, use
// non-standard versions there.
#if defined(__APPLE__) && defined(__aarch64__) && \
defined(__apple_build_version__) && (__apple_build_version__< 6020037)
#define USE_VTBLQ
#endif
#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 = DoGreenShuffle(argb, shuffle);
vst1q_u8((uint8_t*)argb_data, vsubq_u8(argb, greens));
}
// fallthrough and finish off with plain-C
VP8LSubtractGreenFromBlueAndRed_C(argb_data, num_pixels & 3);
}
//------------------------------------------------------------------------------
// Color Transform
static void TransformColor(const VP8LMultipliers* const m,
uint32_t* argb_data, int num_pixels) {
// sign-extended multiplying constants, pre-shifted by 6.
#define CST(X) (((int16_t)(m->X << 8)) >> 6)
const int16_t rb[8] = {
CST(green_to_blue_), CST(green_to_red_),
CST(green_to_blue_), CST(green_to_red_),
CST(green_to_blue_), CST(green_to_red_),
CST(green_to_blue_), CST(green_to_red_)
};
const int16x8_t mults_rb = vld1q_s16(rb);
const int16_t b2[8] = {
0, CST(red_to_blue_), 0, CST(red_to_blue_),
0, CST(red_to_blue_), 0, CST(red_to_blue_),
};
const int16x8_t mults_b2 = vld1q_s16(b2);
#undef CST
#ifdef USE_VTBLQ
static const uint8_t kg0g0[16] = {
255, 1, 255, 1, 255, 5, 255, 5, 255, 9, 255, 9, 255, 13, 255, 13
};
const uint8x16_t shuffle = vld1q_u8(kg0g0);
#else
static const uint8_t k0g0g[8] = { 255, 1, 255, 1, 255, 5, 255, 5 };
const uint8x8_t shuffle = vld1_u8(k0g0g);
#endif
const uint32x4_t mask_rb = vdupq_n_u32(0x00ff00ffu); // red-blue masks
int i;
for (i = 0; i + 4 <= num_pixels; i += 4) {
const uint8x16_t in = vld1q_u8((uint8_t*)(argb_data + i));
// 0 g 0 g
const uint8x16_t greens = DoGreenShuffle(in, shuffle);
// x dr x db1
const int16x8_t A = vqdmulhq_s16(vreinterpretq_s16_u8(greens), mults_rb);
// r 0 b 0
const int16x8_t B = vshlq_n_s16(vreinterpretq_s16_u8(in), 8);
// x db2 0 0
const int16x8_t C = vqdmulhq_s16(B, mults_b2);
// 0 0 x db2
const uint32x4_t D = vshrq_n_u32(vreinterpretq_u32_s16(C), 16);
// x dr x db
const int8x16_t E = vaddq_s8(vreinterpretq_s8_u32(D),
vreinterpretq_s8_s16(A));
// 0 dr 0 db
const uint32x4_t F = vandq_u32(vreinterpretq_u32_s8(E), mask_rb);
const int8x16_t out = vsubq_s8(vreinterpretq_s8_u8(in),
vreinterpretq_s8_u32(F));
vst1q_s8((int8_t*)(argb_data + i), out);
}
// fallthrough and finish off with plain-C
VP8LTransformColor_C(m, argb_data + i, num_pixels - i);
}
#undef USE_VTBLQ
//------------------------------------------------------------------------------
// Entry point
extern void VP8LEncDspInitNEON(void);
WEBP_TSAN_IGNORE_FUNCTION void VP8LEncDspInitNEON(void) {
VP8LSubtractGreenFromBlueAndRed = SubtractGreenFromBlueAndRed;
VP8LTransformColor = TransformColor;
}
#else // !WEBP_USE_NEON
WEBP_DSP_INIT_STUB(VP8LEncDspInitNEON)
#endif // WEBP_USE_NEON