390 lines
14 KiB
C++
390 lines
14 KiB
C++
// Copyright 2015 Google Inc. All Rights Reserved.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
// pack_neon.h: optimized NEON specializations of the templates in pack.h.
|
|
|
|
#ifndef GEMMLOWP_INTERNAL_PACK_NEON_H_
|
|
#define GEMMLOWP_INTERNAL_PACK_NEON_H_
|
|
|
|
#include "pack.h"
|
|
|
|
#include <arm_neon.h>
|
|
|
|
namespace gemmlowp {
|
|
|
|
template <RoundingMode tRoundingMode>
|
|
class NEONRoundingOffsetGenerator {
|
|
public:
|
|
uint8x16_t get() {
|
|
assert(false); // This generic path should never be called.
|
|
return vdupq_n_u8(0);
|
|
}
|
|
};
|
|
|
|
// A RoundingOffsetGenerator for rounding-to-nearest, always returning
|
|
// the midpoint value 127.
|
|
template <>
|
|
class NEONRoundingOffsetGenerator<RoundingMode::Nearest> {
|
|
public:
|
|
uint8x16_t get() { return vdupq_n_u8(127); }
|
|
};
|
|
|
|
// Variant of NEONRoundingOffsetGenerator that produces
|
|
// random NEON 128-bit vectors using a 8-bit Xorshift.
|
|
template <>
|
|
class NEONRoundingOffsetGenerator<RoundingMode::ProbabilisticXorshift> {
|
|
public:
|
|
NEONRoundingOffsetGenerator() {
|
|
uint8_t s = 128;
|
|
std::uint8_t a[16];
|
|
for (int i = 0; i < 16; i++) {
|
|
a[i] = s;
|
|
// Xorshift8(7,7,1). Very important to choose a different
|
|
// xorshift than we do in get(), otherwise lanes would contain
|
|
// the same values!
|
|
s ^= s << 7;
|
|
s ^= s >> 7;
|
|
s ^= s << 1;
|
|
}
|
|
x_ = vld1q_u8(a);
|
|
}
|
|
|
|
uint8x16_t get() {
|
|
// Xorshift produces values in [1..255], we want [0..254].
|
|
uint8x16_t result = vsubq_u8(x_, vdupq_n_u8(1));
|
|
// Xorshift8(7,5,3)
|
|
x_ = veorq_u8(x_, vshlq_n_u8(x_, 7));
|
|
x_ = veorq_u8(x_, vshrq_n_u8(x_, 5));
|
|
x_ = veorq_u8(x_, vshlq_n_u8(x_, 3));
|
|
return result;
|
|
}
|
|
|
|
private:
|
|
// State
|
|
uint8x16_t x_;
|
|
};
|
|
|
|
// Variant of NEONRoundingOffsetGenerator that produces
|
|
// rounding vectors using an 8-bit add/mod low-discrepancy sequence.
|
|
template <>
|
|
class NEONRoundingOffsetGenerator<RoundingMode::ProbabilisticAddmod> {
|
|
public:
|
|
NEONRoundingOffsetGenerator() {
|
|
uint8_t s = 128;
|
|
std::uint8_t a[16];
|
|
// The initial offset is set by offsetting each lane to one
|
|
// more iteration of the sequence (s0...s15) Then, upon iteration,
|
|
// each lane moves ahead by 16.
|
|
for (int i = 0; i < 16; i++) {
|
|
a[i] = s;
|
|
s += (97 + (s >= 158));
|
|
}
|
|
x_ = vld1q_u8(a);
|
|
}
|
|
|
|
uint8x16_t get() {
|
|
// Get moves the lane ahead by 16 iterations of the sequence
|
|
// x_ = (x + (16*97)) % 255. (16*97)%255 = 22. 255-22=233,
|
|
// so x_ += (22 + (x >= 233)).
|
|
// There's an excessively opaque bit hack here:
|
|
// A "true" compare on NEON produces an all-1s result (0xff).
|
|
// So instead of adding in the comparison result, we subtract it
|
|
// to get the same effect as adding 1.
|
|
uint8x16_t extra_one = vcgeq_u8(x_, vdupq_n_u8(233));
|
|
x_ = vaddq_u8(x_, vdupq_n_u8(22));
|
|
x_ = vsubq_u8(x_, extra_one);
|
|
return x_;
|
|
}
|
|
|
|
private:
|
|
// State
|
|
uint8x16_t x_;
|
|
};
|
|
|
|
// Requantizes source uint8 values in [0..255] range
|
|
// to the range specified by BitDepth, [0..((2^bits)-1)].
|
|
// Bias must be avoided. Currently this is achieved
|
|
// by probabilistic rounding.
|
|
template <typename QuantizationParams>
|
|
uint8x16_t Requantize(
|
|
uint8x16_t raw_src_data,
|
|
NEONRoundingOffsetGenerator<QuantizationParams::kRoundingMode>*
|
|
rounding_offset_generator) {
|
|
static const int kBits = QuantizationParams::BitDepth::kBits;
|
|
static const std::uint8_t kMaxVal = (1 << kBits) - 1;
|
|
|
|
if (kBits == 8) {
|
|
return raw_src_data;
|
|
}
|
|
|
|
uint8x16_t rounding_offset = rounding_offset_generator->get();
|
|
|
|
// Compute:
|
|
// x = maxval * src + rounding_offset
|
|
uint16x8_t x[2];
|
|
const uint8x8_t maxval_dup = vdup_n_u8(kMaxVal);
|
|
x[0] = vmlal_u8(vmovl_u8(vget_low_u8(rounding_offset)), maxval_dup,
|
|
vget_low_u8(raw_src_data));
|
|
x[1] = vmlal_u8(vmovl_u8(vget_high_u8(rounding_offset)), maxval_dup,
|
|
vget_high_u8(raw_src_data));
|
|
|
|
// Divide by 255 (truncating).
|
|
//
|
|
// Here we use the following formula, valid for all integers y in 0..65534
|
|
// (which is more than we need since we've already early-returned
|
|
// if kBits==8).
|
|
//
|
|
// y/255 = (y + 1 + (y >> 8)) >> 8.
|
|
uint8x8_t result[2];
|
|
for (int i = 0; i < 2; i++) {
|
|
result[i] = vshrn_n_u16(
|
|
vaddq_u16(vaddq_u16(x[i], vdupq_n_u16(1)), vshrq_n_u16(x[i], 8)), 8);
|
|
}
|
|
|
|
return vcombine_u8(result[0], result[1]);
|
|
}
|
|
|
|
typedef SideMap<const std::uint8_t, SideMapOrder::WidthMajor>
|
|
WidthMajorUint8SideMap;
|
|
|
|
template <int Cells>
|
|
using DepthMajorSideFormatNCells4x2 = KernelSideFormat<CellFormat<4, 2>, Cells>;
|
|
|
|
template <typename QuantizationParams, int Cells>
|
|
class PackingRegisterBlock<
|
|
QuantizationParams, WidthMajorUint8SideMap,
|
|
PackedSideBlock<DepthMajorSideFormatNCells4x2<Cells> > >
|
|
: public PackingRegisterBlockBase<
|
|
QuantizationParams, WidthMajorUint8SideMap,
|
|
PackedSideBlock<DepthMajorSideFormatNCells4x2<Cells> > > {
|
|
public:
|
|
typedef DepthMajorSideFormatNCells4x2<Cells> KernelSideFormat;
|
|
typedef typename KernelSideFormat::Cell CellFormat;
|
|
static const int kCells = KernelSideFormat::kCells;
|
|
static const int kCellWidth = CellFormat::kWidth;
|
|
static const int kKernelWidth = CellFormat::kWidth * kCells;
|
|
static const int kCellDepth = CellFormat::kDepth;
|
|
static const int kCellSize = CellFormat::kSize;
|
|
|
|
typedef NEONRoundingOffsetGenerator<QuantizationParams::kRoundingMode>
|
|
RoundingOffsetGenerator;
|
|
|
|
void Pack(PackedSideBlock<KernelSideFormat>* dst, int start_width,
|
|
RoundingOffsetGenerator* rounding_offset_generator) {
|
|
std::uint8_t* dst_ptr = dst->current_data();
|
|
const std::uint8_t* const src_ptr = this->complete_src_.data();
|
|
const int stride = this->complete_src_.stride();
|
|
// Load and requantize source WidthMajor data
|
|
uint8x16_t src_lines[4 * kCells];
|
|
for (int i = 0; i < 4 * kCells; i++) {
|
|
src_lines[i] = Requantize<QuantizationParams>(
|
|
vld1q_u8(src_ptr + i * stride), rounding_offset_generator);
|
|
}
|
|
// Reorder the data within registers to make DepthMajor 4x2 cells
|
|
uint8x16x2_t src_lines_intertwined_2x[2 * kCells];
|
|
for (int i = 0; i < kCells; i++) {
|
|
src_lines_intertwined_2x[2 * i] =
|
|
vzipq_u8(src_lines[4 * i], src_lines[4 * i + 2]);
|
|
src_lines_intertwined_2x[2 * i + 1] =
|
|
vzipq_u8(src_lines[4 * i + 1], src_lines[4 * i + 3]);
|
|
}
|
|
uint8x16x2_t src_lines_intertwined_4x[2 * kCells];
|
|
for (int i = 0; i < kCells; i++) {
|
|
src_lines_intertwined_4x[2 * i] =
|
|
vzipq_u8(src_lines_intertwined_2x[2 * i].val[0],
|
|
src_lines_intertwined_2x[2 * i + 1].val[0]);
|
|
src_lines_intertwined_4x[2 * i + 1] =
|
|
vzipq_u8(src_lines_intertwined_2x[2 * i].val[1],
|
|
src_lines_intertwined_2x[2 * i + 1].val[1]);
|
|
}
|
|
// Store the resulting DepthMajor 4x2 cells in the destination packed block
|
|
for (int outer = 0; outer < 2; outer++) {
|
|
for (int inner = 0; inner < 2; inner++) {
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
uint8x8_t value = vget_low_u8(
|
|
src_lines_intertwined_4x[2 * cell + outer].val[inner]);
|
|
vst1_u8(dst_ptr, value);
|
|
dst_ptr += 8;
|
|
}
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
uint8x8_t value = vget_high_u8(
|
|
src_lines_intertwined_4x[2 * cell + outer].val[inner]);
|
|
vst1_u8(dst_ptr, value);
|
|
dst_ptr += 8;
|
|
}
|
|
}
|
|
}
|
|
// Compute sums across the depth dimension
|
|
uint16x8_t sums_of_2_cells[kCells][4];
|
|
for (int outer = 0; outer < 2; outer++) {
|
|
for (int inner = 0; inner < 2; inner++) {
|
|
int i = 2 * outer + inner;
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
sums_of_2_cells[cell][i] = vaddl_u8(
|
|
vget_low_u8(
|
|
src_lines_intertwined_4x[2 * cell + outer].val[inner]),
|
|
vget_high_u8(
|
|
src_lines_intertwined_4x[2 * cell + outer].val[inner]));
|
|
}
|
|
}
|
|
}
|
|
int32x4_t sums_of_4_cells[kCells][4];
|
|
for (int i = 0; i < 4; i++) {
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
sums_of_4_cells[cell][i] = vreinterpretq_s32_u32(
|
|
vaddl_u16(vget_low_u16(sums_of_2_cells[cell][i]),
|
|
vget_high_u16(sums_of_2_cells[cell][i])));
|
|
}
|
|
}
|
|
// Update the sums_of_each_slice vector
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
int32x4_t s01 =
|
|
vaddq_s32(sums_of_4_cells[cell][0], sums_of_4_cells[cell][1]);
|
|
int32x4_t s23 =
|
|
vaddq_s32(sums_of_4_cells[cell][2], sums_of_4_cells[cell][3]);
|
|
int32x4_t s = vaddq_s32(s01, s23);
|
|
std::int32_t* sums_of_each_slice_ptr =
|
|
dst->sums_of_each_slice() + start_width + 4 * cell;
|
|
vst1q_s32(sums_of_each_slice_ptr,
|
|
vaddq_s32(s, vld1q_s32(sums_of_each_slice_ptr)));
|
|
}
|
|
dst->seek_forward_n_cells(kCells * kRegisterSize / kCellDepth);
|
|
}
|
|
};
|
|
|
|
template <int Cells>
|
|
using WidthMajorSideFormatNCells4x2 =
|
|
KernelSideFormat<CellFormat<4, 2, CellOrder::WidthMajor>, Cells>;
|
|
|
|
template <typename QuantizationParams, int Cells>
|
|
class PackingRegisterBlock<
|
|
QuantizationParams, WidthMajorUint8SideMap,
|
|
PackedSideBlock<WidthMajorSideFormatNCells4x2<Cells> > >
|
|
: public PackingRegisterBlockBase<
|
|
QuantizationParams, WidthMajorUint8SideMap,
|
|
PackedSideBlock<WidthMajorSideFormatNCells4x2<Cells> > > {
|
|
public:
|
|
typedef WidthMajorSideFormatNCells4x2<Cells> KernelSideFormat;
|
|
typedef typename KernelSideFormat::Cell CellFormat;
|
|
static const int kCells = KernelSideFormat::kCells;
|
|
static const int kCellWidth = CellFormat::kWidth;
|
|
static const int kKernelWidth = CellFormat::kWidth * kCells;
|
|
static const int kCellDepth = CellFormat::kDepth;
|
|
static const int kCellSize = CellFormat::kSize;
|
|
|
|
typedef NEONRoundingOffsetGenerator<QuantizationParams::kRoundingMode>
|
|
RoundingOffsetGenerator;
|
|
|
|
void Pack(PackedSideBlock<KernelSideFormat>* dst, int start_width,
|
|
RoundingOffsetGenerator* rounding_offset_generator) {
|
|
std::uint8_t* dst_ptr = dst->current_data();
|
|
const std::uint8_t* src_ptr = this->complete_src_.data();
|
|
const int stride = this->complete_src_.stride();
|
|
// Load and requantize source WidthMajor data
|
|
uint16x8_t src_lines[kCells * 4];
|
|
for (int i = 0; i < kCells; i++) {
|
|
// This packing path is used with our current
|
|
// less-than-8-bit kernel, and the partial unrolling of this loop
|
|
// results in substantially faster code (thanks to better
|
|
// register allocation) on Nexus 5.
|
|
|
|
#define GEMMLOWP_UNROLLED_LOOP_ITER(k) \
|
|
src_lines[4 * i + k] = vreinterpretq_u16_u8(Requantize<QuantizationParams>( \
|
|
vld1q_u8(src_ptr), rounding_offset_generator)); \
|
|
src_ptr += stride;
|
|
|
|
GEMMLOWP_UNROLLED_LOOP_ITER(0)
|
|
GEMMLOWP_UNROLLED_LOOP_ITER(1)
|
|
GEMMLOWP_UNROLLED_LOOP_ITER(2)
|
|
GEMMLOWP_UNROLLED_LOOP_ITER(3)
|
|
|
|
#undef GEMMLOWP_UNROLLED_LOOP_ITER
|
|
}
|
|
// Reorder the data within registers to make WidthMajor 4x2 cells
|
|
uint16x8x2_t src_lines_intertwined_2x[2 * kCells];
|
|
for (int i = 0; i < kCells; i++) {
|
|
src_lines_intertwined_2x[2 * i] =
|
|
vzipq_u16(src_lines[4 * i], src_lines[4 * i + 2]);
|
|
src_lines_intertwined_2x[2 * i + 1] =
|
|
vzipq_u16(src_lines[4 * i + 1], src_lines[4 * i + 3]);
|
|
}
|
|
uint16x8x2_t src_lines_intertwined_4x[2 * kCells];
|
|
for (int i = 0; i < kCells; i++) {
|
|
src_lines_intertwined_4x[2 * i] =
|
|
vzipq_u16(src_lines_intertwined_2x[2 * i].val[0],
|
|
src_lines_intertwined_2x[2 * i + 1].val[0]);
|
|
src_lines_intertwined_4x[2 * i + 1] =
|
|
vzipq_u16(src_lines_intertwined_2x[2 * i].val[1],
|
|
src_lines_intertwined_2x[2 * i + 1].val[1]);
|
|
}
|
|
// Store the resulting WidthMajor 4x2 cells in the destination packed block
|
|
for (int outer = 0; outer < 2; outer++) {
|
|
for (int inner = 0; inner < 2; inner++) {
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
uint8x8_t value = vreinterpret_u8_u16(vget_low_u16(
|
|
src_lines_intertwined_4x[2 * cell + outer].val[inner]));
|
|
vst1_u8(dst_ptr, value);
|
|
dst_ptr += 8;
|
|
}
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
uint8x8_t value = vreinterpret_u8_u16(vget_high_u16(
|
|
src_lines_intertwined_4x[2 * cell + outer].val[inner]));
|
|
vst1_u8(dst_ptr, value);
|
|
dst_ptr += 8;
|
|
}
|
|
}
|
|
}
|
|
// Compute sums across the depth dimension
|
|
uint16x8_t sums_of_2[kCells][4];
|
|
for (int outer = 0; outer < 2; outer++) {
|
|
for (int inner = 0; inner < 2; inner++) {
|
|
int i = 2 * outer + inner;
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
sums_of_2[cell][i] = vpaddlq_u8(vreinterpretq_u8_u16(
|
|
src_lines_intertwined_4x[2 * cell + outer].val[inner]));
|
|
}
|
|
}
|
|
}
|
|
uint16x8_t sums_of_4[kCells][2];
|
|
for (int i = 0; i < 2; i++) {
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
sums_of_4[cell][i] =
|
|
vaddq_u16(sums_of_2[cell][2 * i], sums_of_2[cell][2 * i + 1]);
|
|
}
|
|
}
|
|
uint16x8_t sums_of_8[kCells];
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
sums_of_8[cell] = vaddq_u16(sums_of_4[cell][0], sums_of_4[cell][1]);
|
|
}
|
|
|
|
uint16x4_t sums_of_16[kCells];
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
sums_of_16[cell] = vadd_u16(vget_low_u16(sums_of_8[cell]),
|
|
vget_high_u16(sums_of_8[cell]));
|
|
}
|
|
// Update the sums_of_each_slice vector
|
|
for (int cell = 0; cell < kCells; cell++) {
|
|
int32x4_t s = vreinterpretq_s32_u32(vmovl_u16(sums_of_16[cell]));
|
|
std::int32_t* sums_of_each_slice_ptr =
|
|
dst->sums_of_each_slice() + start_width + 4 * cell;
|
|
vst1q_s32(sums_of_each_slice_ptr,
|
|
vaddq_s32(s, vld1q_s32(sums_of_each_slice_ptr)));
|
|
}
|
|
dst->seek_forward_n_cells(kCells * kRegisterSize / kCellDepth);
|
|
}
|
|
};
|
|
|
|
} // namespace gemmlowp
|
|
|
|
#endif // GEMMLOWP_INTERNAL_PACK_NEON_H_
|