// Copyright (c) Facebook, Inc. and its affiliates.
// All rights reserved.
//
// Copyright 2019 Google LLC
//
// This source code is licensed under the BSD-style license found in the
// LICENSE file in the root directory of this source tree.

#include <assert.h>

#include <emmintrin.h>
#include <stddef.h>
#include <stdint.h>

#include "xnnpack/avgpool.h"
#include "xnnpack/common.h"
#include "xnnpack/microparams.h"
#include "xnnpack/unaligned.h"


void xnn_qu8_avgpool_minmax_fp32_ukernel_9x__sse2_c8(
    size_t output_pixels,
    size_t kernel_elements,
    size_t channels,
    const uint8_t** input,
    size_t input_offset,
    const uint8_t* zero,
    uint8_t* output,
    size_t input_increment,
    size_t output_increment,
    const struct xnn_qu8_avgpool_minmax_params params[restrict XNN_MIN_ELEMENTS(1)]) XNN_OOB_READS
{
  assert(output_pixels != 0);
  assert(kernel_elements != 0);
  assert(kernel_elements <= 9);
  assert(channels != 0);

  const __m128i vzero = _mm_setzero_si128();
  const __m128i vinit_bias = _mm_set1_epi32(params->fp32_scalar.init_bias);
  const __m128 vscale = _mm_set1_ps(params->fp32_scalar.scale);
  const __m128 voutput_max_less_zero_point = _mm_set1_ps((float) ((int32_t) params->fp32_scalar.output_max - (int32_t) params->fp32_scalar.output_zero_point));
  const __m128i voutput_zero_point = _mm_set1_epi16(params->fp32_scalar.output_zero_point);
  const __m128i voutput_min = _mm_set1_epi8(params->fp32_scalar.output_min);
  XNN_FORCE_REALIZATION(vinit_bias);
  XNN_FORCE_REALIZATION(vscale);
  XNN_FORCE_REALIZATION(voutput_max_less_zero_point);
  XNN_FORCE_REALIZATION(voutput_zero_point);
  XNN_FORCE_REALIZATION(voutput_min);

  do {
    const uint8_t* i0 = input[0];
    assert(i0 != NULL);
    const uint8_t* i1 = input[1];
    const uint8_t* i2 = input[2];
    const uint8_t* i3 = input[3];
    const uint8_t* i4 = input[4];
    const uint8_t* i5 = input[5];
    const uint8_t* i6 = input[6];
    const uint8_t* i7 = input[7];
    const uint8_t* i8 = input[8];
    input = (const uint8_t**) ((uintptr_t) input + input_increment);
    if (kernel_elements < 2) {
      i1 = zero;
    }
    assert(i1 != NULL);
    if (kernel_elements <= 2) {
      i2 = zero;
    }
    assert(i2 != NULL);
    if (kernel_elements < 4) {
      i3 = zero;
    }
    assert(i3 != NULL);
    if (kernel_elements <= 4) {
      i4 = zero;
    }
    assert(i4 != NULL);
    if (kernel_elements < 6) {
      i5 = zero;
    }
    assert(i5 != NULL);
    if (kernel_elements <= 6) {
      i6 = zero;
    }
    assert(i6 != NULL);
    if (kernel_elements < 8) {
      i7 = zero;
    }
    assert(i7 != NULL);
    if (kernel_elements <= 8) {
      i8 = zero;
    }
    assert(i8 != NULL);
    if XNN_UNPREDICTABLE(i0 != zero) {
      i0 = (const uint8_t*) ((uintptr_t) i0 + input_offset);
    }
    if XNN_UNPREDICTABLE(i1 != zero) {
      i1 = (const uint8_t*) ((uintptr_t) i1 + input_offset);
    }
    if XNN_UNPREDICTABLE(i2 != zero) {
      i2 = (const uint8_t*) ((uintptr_t) i2 + input_offset);
    }
    if XNN_UNPREDICTABLE(i3 != zero) {
      i3 = (const uint8_t*) ((uintptr_t) i3 + input_offset);
    }
    if XNN_UNPREDICTABLE(i4 != zero) {
      i4 = (const uint8_t*) ((uintptr_t) i4 + input_offset);
    }
    if XNN_UNPREDICTABLE(i5 != zero) {
      i5 = (const uint8_t*) ((uintptr_t) i5 + input_offset);
    }
    if XNN_UNPREDICTABLE(i6 != zero) {
      i6 = (const uint8_t*) ((uintptr_t) i6 + input_offset);
    }
    if XNN_UNPREDICTABLE(i7 != zero) {
      i7 = (const uint8_t*) ((uintptr_t) i7 + input_offset);
    }
    if XNN_UNPREDICTABLE(i8 != zero) {
      i8 = (const uint8_t*) ((uintptr_t) i8 + input_offset);
    }

    size_t c = channels;
    while (c >= 8) {
      const __m128i vi0 = _mm_loadl_epi64((const __m128i*) i0); i0 += 8;
      const __m128i vi1 = _mm_loadl_epi64((const __m128i*) i1); i1 += 8;
      const __m128i vi2 = _mm_loadl_epi64((const __m128i*) i2); i2 += 8;
      const __m128i vi3 = _mm_loadl_epi64((const __m128i*) i3); i3 += 8;
      const __m128i vi4 = _mm_loadl_epi64((const __m128i*) i4); i4 += 8;
      const __m128i vi5 = _mm_loadl_epi64((const __m128i*) i5); i5 += 8;
      const __m128i vi6 = _mm_loadl_epi64((const __m128i*) i6); i6 += 8;
      const __m128i vi7 = _mm_loadl_epi64((const __m128i*) i7); i7 += 8;
      const __m128i vi8 = _mm_loadl_epi64((const __m128i*) i8); i8 += 8;

      const __m128i vxi0 = _mm_unpacklo_epi8(vi0, vzero);
      const __m128i vxi1 = _mm_unpacklo_epi8(vi1, vzero);
      const __m128i vxi2 = _mm_unpacklo_epi8(vi2, vzero);
      const __m128i vxi3 = _mm_unpacklo_epi8(vi3, vzero);
      const __m128i vxi4 = _mm_unpacklo_epi8(vi4, vzero);
      const __m128i vxi5 = _mm_unpacklo_epi8(vi5, vzero);
      const __m128i vxi6 = _mm_unpacklo_epi8(vi6, vzero);
      const __m128i vxi7 = _mm_unpacklo_epi8(vi7, vzero);
      const __m128i vxi8 = _mm_unpacklo_epi8(vi8, vzero);

      const __m128i vsum018 = _mm_add_epi16(_mm_add_epi16(vxi0, vxi1), vxi8);
      const __m128i vsum23 = _mm_add_epi16(vxi2, vxi3);
      const __m128i vsum45 = _mm_add_epi16(vxi4, vxi5);
      const __m128i vsum67 = _mm_add_epi16(vxi6, vxi7);

      const __m128i vsum2345 = _mm_add_epi16(vsum23, vsum45);
      const __m128i vsum01678 = _mm_add_epi16(vsum018, vsum67);
      const __m128i vsum = _mm_add_epi16(vsum2345, vsum01678);

      __m128i vacc_lo = _mm_add_epi32(vinit_bias, _mm_unpacklo_epi16(vsum, vzero));
      __m128i vacc_hi = _mm_add_epi32(vinit_bias, _mm_unpackhi_epi16(vsum, vzero));

      __m128 vfpacc_lo = _mm_cvtepi32_ps(vacc_lo);
      __m128 vfpacc_hi = _mm_cvtepi32_ps(vacc_hi);

      vfpacc_lo = _mm_mul_ps(vfpacc_lo, vscale);
      vfpacc_hi = _mm_mul_ps(vfpacc_hi, vscale);

      vfpacc_lo = _mm_min_ps(vfpacc_lo, voutput_max_less_zero_point);
      vfpacc_hi = _mm_min_ps(vfpacc_hi, voutput_max_less_zero_point);

      vacc_lo = _mm_cvtps_epi32(vfpacc_lo);
      vacc_hi = _mm_cvtps_epi32(vfpacc_hi);

      __m128i vout = _mm_adds_epi16(_mm_packs_epi32(vacc_lo, vacc_hi), voutput_zero_point);
      vout = _mm_packus_epi16(vout, vout);
      vout = _mm_max_epu8(vout, voutput_min);

      _mm_storel_epi64((__m128i*) output, vout);
      output += 8;

      c -= 8;
    }
    if (c != 0) {
      const __m128i vi0 = _mm_loadl_epi64((const __m128i*) i0);
      const __m128i vi1 = _mm_loadl_epi64((const __m128i*) i1);
      const __m128i vi2 = _mm_loadl_epi64((const __m128i*) i2);
      const __m128i vi3 = _mm_loadl_epi64((const __m128i*) i3);
      const __m128i vi4 = _mm_loadl_epi64((const __m128i*) i4);
      const __m128i vi5 = _mm_loadl_epi64((const __m128i*) i5);
      const __m128i vi6 = _mm_loadl_epi64((const __m128i*) i6);
      const __m128i vi7 = _mm_loadl_epi64((const __m128i*) i7);
      const __m128i vi8 = _mm_loadl_epi64((const __m128i*) i8);

      const __m128i vxi0 = _mm_unpacklo_epi8(vi0, vzero);
      const __m128i vxi1 = _mm_unpacklo_epi8(vi1, vzero);
      const __m128i vxi2 = _mm_unpacklo_epi8(vi2, vzero);
      const __m128i vxi3 = _mm_unpacklo_epi8(vi3, vzero);
      const __m128i vxi4 = _mm_unpacklo_epi8(vi4, vzero);
      const __m128i vxi5 = _mm_unpacklo_epi8(vi5, vzero);
      const __m128i vxi6 = _mm_unpacklo_epi8(vi6, vzero);
      const __m128i vxi7 = _mm_unpacklo_epi8(vi7, vzero);
      const __m128i vxi8 = _mm_unpacklo_epi8(vi8, vzero);

      const __m128i vsum018 = _mm_add_epi16(_mm_add_epi16(vxi0, vxi1), vxi8);
      const __m128i vsum23 = _mm_add_epi16(vxi2, vxi3);
      const __m128i vsum45 = _mm_add_epi16(vxi4, vxi5);
      const __m128i vsum67 = _mm_add_epi16(vxi6, vxi7);

      const __m128i vsum2345 = _mm_add_epi16(vsum23, vsum45);
      const __m128i vsum01678 = _mm_add_epi16(vsum018, vsum67);
      const __m128i vsum = _mm_add_epi16(vsum2345, vsum01678);

      __m128i vacc_lo = _mm_add_epi32(vinit_bias, _mm_unpacklo_epi16(vsum, vzero));
      __m128i vacc_hi = _mm_add_epi32(vinit_bias, _mm_unpackhi_epi16(vsum, vzero));

      __m128 vfpacc_lo = _mm_cvtepi32_ps(vacc_lo);
      __m128 vfpacc_hi = _mm_cvtepi32_ps(vacc_hi);

      vfpacc_lo = _mm_mul_ps(vfpacc_lo, vscale);
      vfpacc_hi = _mm_mul_ps(vfpacc_hi, vscale);

      vfpacc_lo = _mm_min_ps(vfpacc_lo, voutput_max_less_zero_point);
      vfpacc_hi = _mm_min_ps(vfpacc_hi, voutput_max_less_zero_point);

      vacc_lo = _mm_cvtps_epi32(vfpacc_lo);
      vacc_hi = _mm_cvtps_epi32(vfpacc_hi);

      __m128i vout = _mm_adds_epi16(_mm_packs_epi32(vacc_lo, vacc_hi), voutput_zero_point);
      vout = _mm_packus_epi16(vout, vout);
      vout = _mm_max_epu8(vout, voutput_min);

      if (c & 4) {
        unaligned_store_u32(output, (uint32_t) _mm_cvtsi128_si32(vout));
        output += 4;
        vout = _mm_srli_epi64(vout, 32);
      }
      if (c & 2) {
        unaligned_store_u16(output, (uint16_t) _mm_extract_epi16(vout, 0));
        output += 2;
        vout = _mm_srli_epi32(vout, 16);
      }
      if (c & 1) {
        *output = (uint8_t) _mm_cvtsi128_si32(vout);
        output += 1;
      }
    }
    output = (uint8_t*) ((uintptr_t) output + output_increment);
  } while (--output_pixels != 0);
}