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rescaler: add some SSE2 code

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The rounding and arithmetic is not the same as previously, to prevent overflow cases for large upscale factors.

We still rely on 32b x 32b -> 64b multiplies. Raised the fixed-point precision to 32b
so that we have some nice shifts from epi64 to epi32.
Changed rescaler_t type to 'uint32_t' in order to squeeze in all the precision required.

The MIPS code has been disabled because it's now out-of-sync. Will be fixed in
a subsequent CL when the dust settles.
~30-35% faster

Change-Id: I32e4ddc00933f1b1aa3463403086199fd5dad07b
This commit is contained in:
Pascal Massimino 2015-09-25 14:34:02 +02:00
parent 1df1d0eedb
commit 76a7dc39e5
10 changed files with 320 additions and 44 deletions
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1
Android.mk
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@ -62,6 +62,7 @@ dsp_dec_srcs := \
src/dsp/rescaler.c \
src/dsp/rescaler_mips32.c \
src/dsp/rescaler_mips_dsp_r2.c \
src/dsp/rescaler_sse2.c \
src/dsp/upsampling.c \
src/dsp/upsampling_mips_dsp_r2.c \
src/dsp/upsampling_neon.$(NEON) \

1
Makefile.vc
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@ -207,6 +207,7 @@ DSP_DEC_OBJS = \
$(DIROBJ)\dsp\rescaler.obj \
$(DIROBJ)\dsp\rescaler_mips32.obj \
$(DIROBJ)\dsp\rescaler_mips_dsp_r2.obj \
$(DIROBJ)\dsp\rescaler_sse2.obj \
$(DIROBJ)\dsp\upsampling.obj \
$(DIROBJ)\dsp\upsampling_mips_dsp_r2.obj \
$(DIROBJ)\dsp\upsampling_neon.obj \

1
makefile.unix
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@ -149,6 +149,7 @@ DSP_DEC_OBJS = \
src/dsp/rescaler.o \
src/dsp/rescaler_mips32.o \
src/dsp/rescaler_mips_dsp_r2.o \
src/dsp/rescaler_sse2.o \
src/dsp/upsampling.o \
src/dsp/upsampling_mips_dsp_r2.o \
src/dsp/upsampling_neon.o \

1
src/dsp/Makefile.am
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@ -69,6 +69,7 @@ libwebpdspdecode_sse2_la_SOURCES += alpha_processing_sse2.c
libwebpdspdecode_sse2_la_SOURCES += dec_sse2.c
libwebpdspdecode_sse2_la_SOURCES += filters_sse2.c
libwebpdspdecode_sse2_la_SOURCES += lossless_sse2.c
libwebpdspdecode_sse2_la_SOURCES += rescaler_sse2.c
libwebpdspdecode_sse2_la_SOURCES += upsampling_sse2.c
libwebpdspdecode_sse2_la_SOURCES += yuv_sse2.c
libwebpdspdecode_sse2_la_SOURCES += yuv_tables_sse2.h

43
src/dsp/rescaler.c
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@ -100,18 +100,24 @@ void WebPRescalerExportRowExpandC(WebPRescaler* const wrk) {
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(wrk->y_expand);
assert(wrk->y_sub != 0);
if (wrk->y_accum == 0) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int v = (int)MULT_FIX(frow[x_out], wrk->fy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
const uint32_t J = frow[x_out];
const int v = (int)MULT_FIX(J, wrk->fy_scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
}
} else {
const int64_t A = wrk->y_sub + wrk->y_accum;
const int64_t B = -wrk->y_accum;
const uint32_t B = WEBP_RESCALER_FRAC(-wrk->y_accum, wrk->y_sub);
const uint32_t A = WEBP_RESCALER_ONE - B;
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int64_t I = A * frow[x_out] + B * irow[x_out];
const int v = (int)MULT_FIX(I, wrk->fxy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
const uint64_t I = (uint64_t)A * frow[x_out]
+ (uint64_t)B * irow[x_out];
const uint32_t J = (uint32_t)((I + ROUNDER) >> WEBP_RESCALER_RFIX);
const int v = (int)MULT_FIX(J, wrk->fy_scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
}
}
}
@ -122,21 +128,28 @@ void WebPRescalerExportRowShrinkC(WebPRescaler* const wrk) {
rescaler_t* const irow = wrk->irow;
const int x_out_max = wrk->dst_width * wrk->num_channels;
const rescaler_t* const frow = wrk->frow;
const int yscale = wrk->fy_scale * (-wrk->y_accum);
const uint32_t yscale = wrk->fy_scale * (-wrk->y_accum);
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(!wrk->y_expand);
if (yscale) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int frac = (int)MULT_FIX(frow[x_out], yscale);
const uint32_t frac = (uint32_t)MULT_FIX(frow[x_out], yscale);
const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
assert(v >= 0 && v <= 255);
dst[x_out] = v;
irow[x_out] = frac; // new fractional start
}
} else {
} else if (wrk->fxy_scale) {
for (x_out = 0; x_out < x_out_max; ++x_out) {
const int v = (int)MULT_FIX(irow[x_out], wrk->fxy_scale);
dst[x_out] = (!(v & ~0xff)) ? v : (v < 0) ? 0 : 255;
assert(v >= 0 && v <= 255);
dst[x_out] = v;
irow[x_out] = 0;
}
} else { // very special case for src = dst = 1x1
for (x_out = 0; x_out < x_out_max; ++x_out) {
dst[x_out] = irow[x_out];
irow[x_out] = 0;
}
}
@ -179,6 +192,7 @@ WebPRescalerImportRowFunc WebPRescalerImportRowShrink;
WebPRescalerExportRowFunc WebPRescalerExportRowExpand;
WebPRescalerExportRowFunc WebPRescalerExportRowShrink;
extern void WebPRescalerDspInitSSE2(void);
extern void WebPRescalerDspInitMIPS32(void);
extern void WebPRescalerDspInitMIPSdspR2(void);
@ -194,6 +208,11 @@ WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInit(void) {
WebPRescalerExportRowShrink = WebPRescalerExportRowShrinkC;
if (VP8GetCPUInfo != NULL) {
#if defined(WEBP_USE_SSE2)
if (VP8GetCPUInfo(kSSE2)) {
WebPRescalerDspInitSSE2();
}
#endif
#if defined(WEBP_USE_MIPS32)
if (VP8GetCPUInfo(kMIPS32)) {
WebPRescalerDspInitMIPS32();

31
src/dsp/rescaler_mips32.c
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@ -31,7 +31,7 @@ static void ImportRowShrink(WebPRescaler* const wrk, const uint8_t* src) {
for (channel = 0; channel < x_stride; ++channel) {
const uint8_t* src1 = src + channel;
int* frow = wrk->frow + channel;
rescaler_t* frow = wrk->frow + channel;
int temp1, temp2, temp3;
int base, frac, sum;
int accum, accum1;
@ -90,7 +90,7 @@ static void ImportRowExpand(WebPRescaler* const wrk, const uint8_t* src) {
for (channel = 0; channel < x_stride; ++channel) {
const uint8_t* src1 = src + channel;
int* frow = wrk->frow + channel;
rescaler_t* frow = wrk->frow + channel;
int temp1, temp2, temp3, temp4;
int frac;
int accum;
@ -138,18 +138,15 @@ static void ImportRowExpand(WebPRescaler* const wrk, const uint8_t* src) {
}
static void ExportRowShrink(WebPRescaler* const wrk) {
const int x_out_max = wrk->dst_width * wrk->num_channels;
uint8_t* dst = wrk->dst;
rescaler_t* irow = wrk->irow;
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(!wrk->y_expand);
// if wrk->fxy_scale can fit into 32 bits use optimized code,
// otherwise use C code
if ((wrk->fxy_scale >> 32) == 0) {
uint8_t* dst = wrk->dst;
rescaler_t* irow = wrk->irow;
if (wrk->fxy_scale != 0) {
const rescaler_t* frow = wrk->frow;
const int yscale = wrk->fy_scale * (-wrk->y_accum);
const int x_out_max = wrk->dst_width * wrk->num_channels;
int temp0, temp1, temp3, temp4, temp5, temp6, temp7, loop_end;
const int temp2 = (int)(wrk->fxy_scale);
const int temp8 = x_out_max << 2;
@ -192,8 +189,12 @@ static void ExportRowShrink(WebPRescaler* const wrk) {
: [temp2]"r"(temp2), [yscale]"r"(yscale), [temp8]"r"(temp8)
: "memory", "hi", "lo"
);
} else {
WebPRescalerExportRowShrinkC(wrk);
} else { // very special case for src = dst = 1x1
int x_out;
for (x_out = 0; x_out < x_out_max; ++x_out) {
dst[x_out] = irow[x_out];
irow[x_out] = 0;
}
}
}
@ -205,9 +206,17 @@ static void ExportRowShrink(WebPRescaler* const wrk) {
extern void WebPRescalerDspInitMIPS32(void);
WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInitMIPS32(void) {
#if 0
// The assembly code is currently out-of-sync wrt the C-implementation.
// Disabled for now.
WebPRescalerImportRowExpand = ImportRowExpand;
WebPRescalerImportRowShrink = ImportRowShrink;
WebPRescalerExportRowShrink = ExportRowShrink;
#else
(void)ImportRowExpand;
(void)ImportRowShrink;
(void)ExportRowShrink;
#endif
}
#else // !WEBP_USE_MIPS32

30
src/dsp/rescaler_mips_dsp_r2.c
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@ -30,7 +30,7 @@ static void ImportRowShrink(WebPRescaler* const wrk, const uint8_t* src) {
assert(!WebPRescalerInputDone(wrk));
for (channel = 0; channel < x_stride; ++channel) {
int* frow = wrk->frow + channel;
rescaler_t* frow = wrk->frow + channel;
const uint8_t* src1 = src + channel;
int temp3;
int base, frac, sum;
@ -84,7 +84,7 @@ static void ImportRowExpand(WebPRescaler* const wrk, const uint8_t* src) {
assert(!WebPRescalerInputDone(wrk));
for (channel = 0; channel < x_stride; ++channel) {
int* frow = wrk->frow + channel;
rescaler_t* frow = wrk->frow + channel;
const uint8_t* src1 = src + channel;
int temp1, temp2, temp3, temp4;
int frac;
@ -133,17 +133,15 @@ static void ImportRowExpand(WebPRescaler* const wrk, const uint8_t* src) {
}
static void ExportRowShrink(WebPRescaler* const wrk) {
uint8_t* dst = wrk->dst;
rescaler_t* irow = wrk->irow;
const int x_out_max = wrk->dst_width * wrk->num_channels;
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(!wrk->y_expand);
// if wrk->fxy_scale can fit into 32 bits use optimized code,
// otherwise use C code
if ((wrk->fxy_scale >> 32) == 0) {
uint8_t* dst = wrk->dst;
rescaler_t* irow = wrk->irow;
if (wrk->fxy_scale) {
const rescaler_t* frow = wrk->frow;
const int yscale = wrk->fy_scale * (-wrk->y_accum);
const int x_out_max = wrk->dst_width * wrk->num_channels;
int temp0, temp1, temp3, temp4, temp5, temp6, temp7;
const int temp2 = (int)wrk->fxy_scale;
@ -212,8 +210,12 @@ static void ExportRowShrink(WebPRescaler* const wrk) {
[rest]"r"(rest)
: "memory", "hi", "lo"
);
} else {
WebPRescalerExportRowShrinkC(wrk);
} else { // very special case for src = dst = 1x1
int x_out;
for (x_out = 0; x_out < x_out_max; ++x_out) {
dst[x_out] = irow[x_out];
irow[x_out] = 0;
}
}
}
@ -225,9 +227,17 @@ static void ExportRowShrink(WebPRescaler* const wrk) {
extern void WebPRescalerDspInitMIPSdspR2(void);
WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInitMIPSdspR2(void) {
#if 0
// The assembly code is currently out-of-sync wrt the C-implementation.
// Disabled for now.
WebPRescalerImportRowExpand = ImportRowExpand;
WebPRescalerImportRowShrink = ImportRowShrink;
WebPRescalerExportRowShrink = ExportRowShrink;
#else
(void)ImportRowExpand;
(void)ImportRowShrink;
(void)ExportRowShrink;
#endif
}
#else // !WEBP_USE_MIPS_DSP_R2

232
src/dsp/rescaler_sse2.c Normal file
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@ -0,0 +1,232 @@
// 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.
// -----------------------------------------------------------------------------
//
// SSE2 Rescaling functions
//
// Author: Skal (pascal.massimino@gmail.com)
#include "./dsp.h"
#if defined(WEBP_USE_SSE2)
#include <emmintrin.h>
#include <assert.h>
#include "../utils/rescaler.h"
//------------------------------------------------------------------------------
// Implementations of critical functions ImportRow / ExportRow
#define ROUNDER (WEBP_RESCALER_ONE >> 1)
#define MULT_FIX(x, y) (((uint64_t)(x) * (y) + ROUNDER) >> WEBP_RESCALER_RFIX)
//------------------------------------------------------------------------------
// Row export
// load *src as epi64, multiply by mult and store result in [out0 ... out3]
static WEBP_INLINE void LoadDispatchAndMult(const rescaler_t* const src,
const __m128i* const mult,
__m128i* const out0,
__m128i* const out1,
__m128i* const out2,
__m128i* const out3) {
const __m128i A0 = _mm_loadu_si128((const __m128i*)(src + 0));
const __m128i A1 = _mm_loadu_si128((const __m128i*)(src + 4));
const __m128i A2 = _mm_srli_epi64(A0, 32);
const __m128i A3 = _mm_srli_epi64(A1, 32);
if (mult != NULL) {
*out0 = _mm_mul_epu32(A0, *mult);
*out1 = _mm_mul_epu32(A1, *mult);
*out2 = _mm_mul_epu32(A2, *mult);
*out3 = _mm_mul_epu32(A3, *mult);
} else {
*out0 = A0;
*out1 = A1;
*out2 = A2;
*out3 = A3;
}
}
static WEBP_INLINE void ProcessRow(const __m128i* const A0,
const __m128i* const A1,
const __m128i* const A2,
const __m128i* const A3,
const __m128i* const mult,
uint8_t* const dst) {
const __m128i rounder = _mm_set_epi64x(ROUNDER, ROUNDER);
const __m128i mask = _mm_set_epi64x(0xffffffff00000000ull,
0xffffffff00000000ull);
const __m128i B0 = _mm_mul_epu32(*A0, *mult);
const __m128i B1 = _mm_mul_epu32(*A1, *mult);
const __m128i B2 = _mm_mul_epu32(*A2, *mult);
const __m128i B3 = _mm_mul_epu32(*A3, *mult);
const __m128i C0 = _mm_add_epi64(B0, rounder);
const __m128i C1 = _mm_add_epi64(B1, rounder);
const __m128i C2 = _mm_add_epi64(B2, rounder);
const __m128i C3 = _mm_add_epi64(B3, rounder);
const __m128i D0 = _mm_srli_epi64(C0, WEBP_RESCALER_RFIX);
const __m128i D1 = _mm_srli_epi64(C1, WEBP_RESCALER_RFIX);
const __m128i D2 = _mm_and_si128(C2, mask);
const __m128i D3 = _mm_and_si128(C3, mask);
const __m128i E0 = _mm_or_si128(D0, D2);
const __m128i E1 = _mm_or_si128(D1, D3);
const __m128i F = _mm_packs_epi32(E0, E1);
const __m128i G = _mm_packus_epi16(F, F);
_mm_storel_epi64((__m128i*)dst, G);
}
static void RescalerExportRowExpandSSE2(WebPRescaler* const wrk) {
int x_out;
uint8_t* const dst = wrk->dst;
rescaler_t* const irow = wrk->irow;
const int x_out_max = wrk->dst_width * wrk->num_channels;
const rescaler_t* const frow = wrk->frow;
const __m128i mult = _mm_set_epi64x(wrk->fy_scale, wrk->fy_scale);
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0 && wrk->y_sub + wrk->y_accum >= 0);
assert(wrk->y_expand);
if (wrk->y_accum == 0) {
for (x_out = 0; x_out + 8 <= x_out_max; x_out += 8) {
__m128i A0, A1, A2, A3;
LoadDispatchAndMult(frow + x_out, NULL, &A0, &A1, &A2, &A3);
ProcessRow(&A0, &A1, &A2, &A3, &mult, dst + x_out);
}
for (; x_out < x_out_max; ++x_out) {
const uint32_t J = frow[x_out];
const int v = (int)MULT_FIX(J, wrk->fy_scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
}
} else {
const uint32_t B = WEBP_RESCALER_FRAC(-wrk->y_accum, wrk->y_sub);
const uint32_t A = WEBP_RESCALER_ONE - B;
const __m128i mA = _mm_set_epi64x(A, A);
const __m128i mB = _mm_set_epi64x(B, B);
const __m128i rounder = _mm_set_epi64x(ROUNDER, ROUNDER);
for (x_out = 0; x_out + 8 <= x_out_max; x_out += 8) {
__m128i A0, A1, A2, A3, B0, B1, B2, B3;
LoadDispatchAndMult(frow + x_out, &mA, &A0, &A1, &A2, &A3);
LoadDispatchAndMult(irow + x_out, &mB, &B0, &B1, &B2, &B3);
{
const __m128i C0 = _mm_add_epi64(A0, B0);
const __m128i C1 = _mm_add_epi64(A1, B1);
const __m128i C2 = _mm_add_epi64(A2, B2);
const __m128i C3 = _mm_add_epi64(A3, B3);
const __m128i D0 = _mm_add_epi64(C0, rounder);
const __m128i D1 = _mm_add_epi64(C1, rounder);
const __m128i D2 = _mm_add_epi64(C2, rounder);
const __m128i D3 = _mm_add_epi64(C3, rounder);
const __m128i E0 = _mm_srli_epi64(D0, WEBP_RESCALER_RFIX);
const __m128i E1 = _mm_srli_epi64(D1, WEBP_RESCALER_RFIX);
const __m128i E2 = _mm_srli_epi64(D2, WEBP_RESCALER_RFIX);
const __m128i E3 = _mm_srli_epi64(D3, WEBP_RESCALER_RFIX);
ProcessRow(&E0, &E1, &E2, &E3, &mult, dst + x_out);
}
}
for (; x_out < x_out_max; ++x_out) {
const uint64_t I = (uint64_t)A * frow[x_out]
+ (uint64_t)B * irow[x_out];
const uint32_t J = (uint32_t)((I + ROUNDER) >> WEBP_RESCALER_RFIX);
const int v = (int)MULT_FIX(J, wrk->fy_scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
}
}
}
static void RescalerExportRowShrinkSSE2(WebPRescaler* const wrk) {
int x_out;
uint8_t* const dst = wrk->dst;
rescaler_t* const irow = wrk->irow;
const int x_out_max = wrk->dst_width * wrk->num_channels;
const rescaler_t* const frow = wrk->frow;
const uint32_t yscale = wrk->fy_scale * (-wrk->y_accum);
assert(!WebPRescalerOutputDone(wrk));
assert(wrk->y_accum <= 0);
assert(!wrk->y_expand);
if (yscale) {
const int scale_xy = wrk->fxy_scale;
const __m128i mult_xy = _mm_set_epi64x(scale_xy, scale_xy);
const __m128i mult_y = _mm_set_epi64x(yscale, yscale);
const __m128i rounder = _mm_set_epi64x(ROUNDER, ROUNDER);
for (x_out = 0; x_out + 8 <= x_out_max; x_out += 8) {
__m128i A0, A1, A2, A3, B0, B1, B2, B3;
LoadDispatchAndMult(irow + x_out, NULL, &A0, &A1, &A2, &A3);
LoadDispatchAndMult(frow + x_out, &mult_y, &B0, &B1, &B2, &B3);
{
const __m128i C0 = _mm_add_epi64(B0, rounder);
const __m128i C1 = _mm_add_epi64(B1, rounder);
const __m128i C2 = _mm_add_epi64(B2, rounder);
const __m128i C3 = _mm_add_epi64(B3, rounder);
const __m128i D0 = _mm_srli_epi64(C0, WEBP_RESCALER_RFIX); // = frac
const __m128i D1 = _mm_srli_epi64(C1, WEBP_RESCALER_RFIX);
const __m128i D2 = _mm_srli_epi64(C2, WEBP_RESCALER_RFIX);
const __m128i D3 = _mm_srli_epi64(C3, WEBP_RESCALER_RFIX);
const __m128i E0 = _mm_sub_epi64(A0, D0); // irow[x] - frac
const __m128i E1 = _mm_sub_epi64(A1, D1);
const __m128i E2 = _mm_sub_epi64(A2, D2);
const __m128i E3 = _mm_sub_epi64(A3, D3);
const __m128i F2 = _mm_slli_epi64(D2, 32);
const __m128i F3 = _mm_slli_epi64(D3, 32);
const __m128i G0 = _mm_or_si128(D0, F2);
const __m128i G1 = _mm_or_si128(D1, F3);
_mm_storeu_si128((__m128i*)(irow + x_out + 0), G0);
_mm_storeu_si128((__m128i*)(irow + x_out + 4), G1);
ProcessRow(&E0, &E1, &E2, &E3, &mult_xy, dst + x_out);
}
}
for (; x_out < x_out_max; ++x_out) {
const uint32_t frac = (int)MULT_FIX(frow[x_out], yscale);
const int v = (int)MULT_FIX(irow[x_out] - frac, wrk->fxy_scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
irow[x_out] = frac; // new fractional start
}
} else if (wrk->fxy_scale) {
const uint32_t scale = wrk->fxy_scale;
const __m128i mult = _mm_set_epi64x(scale, scale);
const __m128i zero = _mm_setzero_si128();
for (x_out = 0; x_out + 8 <= x_out_max; x_out += 8) {
__m128i A0, A1, A2, A3;
LoadDispatchAndMult(irow + x_out, NULL, &A0, &A1, &A2, &A3);
_mm_storeu_si128((__m128i*)(irow + x_out + 0), zero);
_mm_storeu_si128((__m128i*)(irow + x_out + 4), zero);
ProcessRow(&A0, &A1, &A2, &A3, &mult, dst + x_out);
}
for (; x_out < x_out_max; ++x_out) {
const int v = (int)MULT_FIX(irow[x_out], scale);
assert(v >= 0 && v <= 255);
dst[x_out] = v;
irow[x_out] = 0;
}
} else { // very special case for src = 1x1
for (x_out = 0; x_out < x_out_max; ++x_out) {
dst[x_out] = irow[x_out];
irow[x_out] = 0;
}
}
}
#undef MULT_FIX
#undef ROUNDER
//------------------------------------------------------------------------------
extern void WebPRescalerDspInitSSE2(void);
WEBP_TSAN_IGNORE_FUNCTION void WebPRescalerDspInitSSE2(void) {
WebPRescalerExportRowExpand = RescalerExportRowExpandSSE2;
WebPRescalerExportRowShrink = RescalerExportRowShrinkSSE2;
}
#else // !WEBP_USE_SSE2
WEBP_DSP_INIT_STUB(WebPRescalerDspInitSSE2)
#endif // WEBP_USE_SSE2

13
src/utils/rescaler.c
View File

@ -41,19 +41,20 @@ void WebPRescalerInit(WebPRescaler* const wrk, int src_width, int src_height,
wrk->x_add = wrk->x_expand ? (x_sub - 1) : x_add;
wrk->x_sub = wrk->x_expand ? (x_add - 1) : x_sub;
if (!wrk->x_expand) { // fx_scale is not used otherwise
wrk->fx_scale = WEBP_RESCALER_ONE / wrk->x_sub;
wrk->fx_scale = WEBP_RESCALER_FRAC(1, wrk->x_sub);
}
// vertical scaling parameters
wrk->y_add = wrk->y_expand ? y_add - 1 : y_add;
wrk->y_sub = wrk->y_expand ? y_sub - 1 : y_sub;
wrk->y_accum = wrk->y_expand ? wrk->y_sub : wrk->y_add;
if (!wrk->y_expand) {
wrk->fy_scale = WEBP_RESCALER_ONE / wrk->y_sub;
wrk->fxy_scale = ((uint64_t)dst_height << WEBP_RESCALER_RFIX)
/ (wrk->x_add * wrk->y_add);
// note the very special case where x_add = y_add = 1 cannot be represented.
// We special-case fxy_scale = 0 in this case, in ExportRowShrink
wrk->fxy_scale = WEBP_RESCALER_FRAC(dst_height, wrk->x_add * wrk->y_add);
wrk->fy_scale = WEBP_RESCALER_FRAC(1, wrk->y_sub);
} else {
wrk->fy_scale = WEBP_RESCALER_ONE / wrk->x_add;
wrk->fxy_scale = WEBP_RESCALER_ONE / (wrk->x_add * wrk->y_sub);
wrk->fy_scale = WEBP_RESCALER_FRAC(1, wrk->x_add);
// wrk->fxy_scale is unused here.
}
wrk->irow = work;
wrk->frow = work + num_channels * dst_width;

9
src/utils/rescaler.h
View File

@ -20,11 +20,12 @@ extern "C" {
#include "../webp/types.h"
#define WEBP_RESCALER_RFIX 30 // fixed-point precision for multiplies
#define WEBP_RESCALER_ONE (1u << WEBP_RESCALER_RFIX)
#define WEBP_RESCALER_RFIX 32 // fixed-point precision for multiplies
#define WEBP_RESCALER_ONE (1ull << WEBP_RESCALER_RFIX)
#define WEBP_RESCALER_FRAC(x, y) (((uint64_t)(x) << WEBP_RESCALER_RFIX) / (y))
// Structure used for on-the-fly rescaling
typedef int32_t rescaler_t; // type for side-buffer
typedef uint32_t rescaler_t; // type for side-buffer
typedef struct WebPRescaler WebPRescaler;
struct WebPRescaler {
int x_expand; // true if we're expanding in the x direction
@ -32,7 +33,7 @@ struct WebPRescaler {
int num_channels; // bytes to jump between pixels
uint32_t fx_scale; // fixed-point scaling factors
uint32_t fy_scale; // ''
uint64_t fxy_scale; // ''
uint32_t fxy_scale; // ''
int y_accum; // vertical accumulator
int y_add, y_sub; // vertical increments
int x_add, x_sub; // horizontal increments