text: /*
   * Copyright (c) 2016, Alliance for Open Media. All rights reserved
   *
   * This source code is subject to the terms of the BSD 2 Clause License and
   * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
   * was not distributed with this source code in the LICENSE file, you can
   * obtain it at www.aomedia.org/license/software. If the Alliance for Open
   * Media Patent License 1.0 was not distributed with this source code in the
   * PATENTS file, you can obtain it at www.aomedia.org/license/patent.
   */
  
  #include <assert.h>
  #include <stdio.h>
  
  #include "./aom_dsp_rtcd.h"
  #include "aom_dsp/mips/convolve_common_dspr2.h"
  #include "aom_dsp/aom_convolve.h"
  #include "aom_dsp/aom_dsp_common.h"
  #include "aom_ports/mem.h"
  
  #if HAVE_DSPR2
  static void convolve_avg_vert_4_dspr2(const uint8_t *src, int32_t src_stride,
                                        uint8_t *dst, int32_t dst_stride,
                                        const int16_t *filter_y, int32_t w,
                                        int32_t h) {
    int32_t x, y;
    const uint8_t *src_ptr;
    uint8_t *dst_ptr;
    uint8_t *cm = aom_ff_cropTbl;
    uint32_t vector4a = 64;
    uint32_t load1, load2, load3, load4;
    uint32_t p1, p2;
    uint32_t n1, n2;
    uint32_t scratch1, scratch2;
    uint32_t store1, store2;
    int32_t vector1b, vector2b, vector3b, vector4b;
    int32_t Temp1, Temp2;
  
    vector1b = ((const int32_t *)filter_y)[0];
    vector2b = ((const int32_t *)filter_y)[1];
    vector3b = ((const int32_t *)filter_y)[2];
    vector4b = ((const int32_t *)filter_y)[3];
  
    src -= 3 * src_stride;
  
    for (y = h; y--;) {
      /* prefetch data to cache memory */
      prefetch_store(dst + dst_stride);
  
      for (x = 0; x < w; x += 4) {
        src_ptr = src + x;
        dst_ptr = dst + x;
  
        __asm__ __volatile__(
            "ulw              %[load1],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load2],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load3],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load4],     0(%[src_ptr])                   \n\t"
  
            "mtlo             %[vector4a],  $ac0                            \n\t"
            "mtlo             %[vector4a],  $ac1                            \n\t"
            "mtlo             %[vector4a],  $ac2                            \n\t"
            "mtlo             %[vector4a],  $ac3                            \n\t"
            "mthi             $zero,        $ac0                            \n\t"
            "mthi             $zero,        $ac1                            \n\t"
            "mthi             $zero,        $ac2                            \n\t"
            "mthi             $zero,        $ac3                            \n\t"
  
            "preceu.ph.qbr    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbr    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "preceu.ph.qbr    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbr    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
  
            "dpa.w.ph         $ac0,         %[p1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac0,         %[p2],          %[vector2b]     \n\t"
            "dpa.w.ph         $ac1,         %[n1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac1,         %[n2],          %[vector2b]     \n\t"
  
            "preceu.ph.qbl    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbl    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "preceu.ph.qbl    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbl    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
  
            "dpa.w.ph         $ac2,         %[p1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac2,         %[p2],          %[vector2b]     \n\t"
            "dpa.w.ph         $ac3,         %[n1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac3,         %[n2],          %[vector2b]     \n\t"
  
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load1],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load2],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load3],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load4],     0(%[src_ptr])                   \n\t"
  
            "preceu.ph.qbr    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbr    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "preceu.ph.qbr    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbr    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
  
            "dpa.w.ph         $ac0,         %[p1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac0,         %[p2],          %[vector4b]     \n\t"
            "extp             %[Temp1],     $ac0,           31              \n\t"
            "dpa.w.ph         $ac1,         %[n1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac1,         %[n2],          %[vector4b]     \n\t"
            "extp             %[Temp2],     $ac1,           31              \n\t"
  
            "preceu.ph.qbl    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbl    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "lbu              %[scratch1],  0(%[dst_ptr])                   \n\t"
            "preceu.ph.qbl    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbl    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
            "lbu              %[scratch2],  1(%[dst_ptr])                   \n\t"
  
            "lbux             %[store1],    %[Temp1](%[cm])                 \n\t"
            "dpa.w.ph         $ac2,         %[p1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac2,         %[p2],          %[vector4b]     \n\t"
            "addqh_r.w        %[store1],    %[store1],      %[scratch1]     \n\t" /* pixel 1 */
            "extp             %[Temp1],     $ac2,           31              \n\t"
  
            "lbux             %[store2],    %[Temp2](%[cm])                 \n\t"
            "dpa.w.ph         $ac3,         %[n1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac3,         %[n2],          %[vector4b]     \n\t"
            "addqh_r.w        %[store2],    %[store2],      %[scratch2]     \n\t" /* pixel 2 */
            "extp             %[Temp2],     $ac3,           31              \n\t"
            "lbu              %[scratch1],  2(%[dst_ptr])                   \n\t"
  
            "sb               %[store1],    0(%[dst_ptr])                   \n\t"
            "sb               %[store2],    1(%[dst_ptr])                   \n\t"
            "lbu              %[scratch2],  3(%[dst_ptr])                   \n\t"
  
            "lbux             %[store1],    %[Temp1](%[cm])                 \n\t"
            "lbux             %[store2],    %[Temp2](%[cm])                 \n\t"
            "addqh_r.w        %[store1],    %[store1],      %[scratch1]     \n\t" /* pixel 3 */
            "addqh_r.w        %[store2],    %[store2],      %[scratch2]     \n\t" /* pixel 4 */
  
            "sb               %[store1],    2(%[dst_ptr])                   \n\t"
            "sb               %[store2],    3(%[dst_ptr])                   \n\t"
  
            : [load1] "=&r"(load1), [load2] "=&r"(load2), [load3] "=&r"(load3),
              [load4] "=&r"(load4), [p1] "=&r"(p1), [p2] "=&r"(p2),
              [n1] "=&r"(n1), [n2] "=&r"(n2), [scratch1] "=&r"(scratch1),
              [scratch2] "=&r"(scratch2), [Temp1] "=&r"(Temp1),
              [Temp2] "=&r"(Temp2), [store1] "=&r"(store1),
              [store2] "=&r"(store2), [src_ptr] "+r"(src_ptr)
            : [vector1b] "r"(vector1b), [vector2b] "r"(vector2b),
              [vector3b] "r"(vector3b), [vector4b] "r"(vector4b),
              [vector4a] "r"(vector4a), [src_stride] "r"(src_stride),
              [cm] "r"(cm), [dst_ptr] "r"(dst_ptr));
      }
  
      /* Next row... */
      src += src_stride;
      dst += dst_stride;
    }
  }
  
  static void convolve_avg_vert_64_dspr2(const uint8_t *src, int32_t src_stride,
                                         uint8_t *dst, int32_t dst_stride,
                                         const int16_t *filter_y, int32_t h) {
    int32_t x, y;
    const uint8_t *src_ptr;
    uint8_t *dst_ptr;
    uint8_t *cm = aom_ff_cropTbl;
    uint32_t vector4a = 64;
    uint32_t load1, load2, load3, load4;
    uint32_t p1, p2;
    uint32_t n1, n2;
    uint32_t scratch1, scratch2;
    uint32_t store1, store2;
    int32_t vector1b, vector2b, vector3b, vector4b;
    int32_t Temp1, Temp2;
  
    vector1b = ((const int32_t *)filter_y)[0];
    vector2b = ((const int32_t *)filter_y)[1];
    vector3b = ((const int32_t *)filter_y)[2];
    vector4b = ((const int32_t *)filter_y)[3];
  
    src -= 3 * src_stride;
  
    for (y = h; y--;) {
      /* prefetch data to cache memory */
      prefetch_store(dst + dst_stride);
      prefetch_store(dst + dst_stride + 32);
  
      for (x = 0; x < 64; x += 4) {
        src_ptr = src + x;
        dst_ptr = dst + x;
  
        __asm__ __volatile__(
            "ulw              %[load1],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load2],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load3],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load4],     0(%[src_ptr])                   \n\t"
  
            "mtlo             %[vector4a],  $ac0                            \n\t"
            "mtlo             %[vector4a],  $ac1                            \n\t"
            "mtlo             %[vector4a],  $ac2                            \n\t"
            "mtlo             %[vector4a],  $ac3                            \n\t"
            "mthi             $zero,        $ac0                            \n\t"
            "mthi             $zero,        $ac1                            \n\t"
            "mthi             $zero,        $ac2                            \n\t"
            "mthi             $zero,        $ac3                            \n\t"
  
            "preceu.ph.qbr    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbr    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "preceu.ph.qbr    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbr    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
  
            "dpa.w.ph         $ac0,         %[p1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac0,         %[p2],          %[vector2b]     \n\t"
            "dpa.w.ph         $ac1,         %[n1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac1,         %[n2],          %[vector2b]     \n\t"
  
            "preceu.ph.qbl    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbl    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "preceu.ph.qbl    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbl    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
  
            "dpa.w.ph         $ac2,         %[p1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac2,         %[p2],          %[vector2b]     \n\t"
            "dpa.w.ph         $ac3,         %[n1],          %[vector1b]     \n\t"
            "dpa.w.ph         $ac3,         %[n2],          %[vector2b]     \n\t"
  
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load1],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load2],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load3],     0(%[src_ptr])                   \n\t"
            "add              %[src_ptr],   %[src_ptr],     %[src_stride]   \n\t"
            "ulw              %[load4],     0(%[src_ptr])                   \n\t"
  
            "preceu.ph.qbr    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbr    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "preceu.ph.qbr    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbr    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
  
            "dpa.w.ph         $ac0,         %[p1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac0,         %[p2],          %[vector4b]     \n\t"
            "extp             %[Temp1],     $ac0,           31              \n\t"
            "dpa.w.ph         $ac1,         %[n1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac1,         %[n2],          %[vector4b]     \n\t"
            "extp             %[Temp2],     $ac1,           31              \n\t"
  
            "preceu.ph.qbl    %[scratch1],  %[load1]                        \n\t"
            "preceu.ph.qbl    %[p1],        %[load2]                        \n\t"
            "precrq.ph.w      %[n1],        %[p1],          %[scratch1]     \n\t" /* pixel 2 */
            "append           %[p1],        %[scratch1],    16              \n\t" /* pixel 1 */
            "lbu              %[scratch1],  0(%[dst_ptr])                   \n\t"
            "preceu.ph.qbl    %[scratch2],  %[load3]                        \n\t"
            "preceu.ph.qbl    %[p2],        %[load4]                        \n\t"
            "precrq.ph.w      %[n2],        %[p2],          %[scratch2]     \n\t" /* pixel 2 */
            "append           %[p2],        %[scratch2],    16              \n\t" /* pixel 1 */
            "lbu              %[scratch2],  1(%[dst_ptr])                   \n\t"
  
            "lbux             %[store1],    %[Temp1](%[cm])                 \n\t"
            "dpa.w.ph         $ac2,         %[p1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac2,         %[p2],          %[vector4b]     \n\t"
            "addqh_r.w        %[store1],    %[store1],      %[scratch1]     \n\t" /* pixel 1 */
            "extp             %[Temp1],     $ac2,           31              \n\t"
  
            "lbux             %[store2],    %[Temp2](%[cm])                 \n\t"
            "dpa.w.ph         $ac3,         %[n1],          %[vector3b]     \n\t"
            "dpa.w.ph         $ac3,         %[n2],          %[vector4b]     \n\t"
            "addqh_r.w        %[store2],    %[store2],      %[scratch2]     \n\t" /* pixel 2 */
            "extp             %[Temp2],     $ac3,           31              \n\t"
            "lbu              %[scratch1],  2(%[dst_ptr])                   \n\t"
  
            "sb               %[store1],    0(%[dst_ptr])                   \n\t"
            "sb               %[store2],    1(%[dst_ptr])                   \n\t"
            "lbu              %[scratch2],  3(%[dst_ptr])                   \n\t"
  
            "lbux             %[store1],    %[Temp1](%[cm])                 \n\t"
            "lbux             %[store2],    %[Temp2](%[cm])                 \n\t"
            "addqh_r.w        %[store1],    %[store1],      %[scratch1]     \n\t" /* pixel 3 */
            "addqh_r.w        %[store2],    %[store2],      %[scratch2]     \n\t" /* pixel 4 */
  
            "sb               %[store1],    2(%[dst_ptr])                   \n\t"
            "sb               %[store2],    3(%[dst_ptr])                   \n\t"
  
            : [load1] "=&r"(load1), [load2] "=&r"(load2), [load3] "=&r"(load3),
              [load4] "=&r"(load4), [p1] "=&r"(p1), [p2] "=&r"(p2),
              [n1] "=&r"(n1), [n2] "=&r"(n2), [scratch1] "=&r"(scratch1),
              [scratch2] "=&r"(scratch2), [Temp1] "=&r"(Temp1),
              [Temp2] "=&r"(Temp2), [store1] "=&r"(store1),
              [store2] "=&r"(store2), [src_ptr] "+r"(src_ptr)
            : [vector1b] "r"(vector1b), [vector2b] "r"(vector2b),
              [vector3b] "r"(vector3b), [vector4b] "r"(vector4b),
              [vector4a] "r"(vector4a), [src_stride] "r"(src_stride),
              [cm] "r"(cm), [dst_ptr] "r"(dst_ptr));
      }
  
      /* Next row... */
      src += src_stride;
      dst += dst_stride;
    }
  }
  
  void aom_convolve8_avg_vert_dspr2(const uint8_t *src, ptrdiff_t src_stride,
                                    uint8_t *dst, ptrdiff_t dst_stride,
                                    const int16_t *filter_x, int x_step_q4,
                                    const int16_t *filter_y, int y_step_q4, int w,
                                    int h) {
    assert(y_step_q4 == 16);
    assert(((const int32_t *)filter_y)[1] != 0x800000);
  
    if (((const int32_t *)filter_y)[0] == 0) {
      aom_convolve2_avg_vert_dspr2(src, src_stride, dst, dst_stride, filter_x,
                                   x_step_q4, filter_y, y_step_q4, w, h);
    } else {
      uint32_t pos = 38;
  
      /* bit positon for extract from acc */
      __asm__ __volatile__("wrdsp      %[pos],     1           \n\t"
                           :
                           : [pos] "r"(pos));
  
      prefetch_store(dst);
  
      switch (w) {
        case 4:
        case 8:
        case 16:
        case 32:
          convolve_avg_vert_4_dspr2(src, src_stride, dst, dst_stride, filter_y, w,
                                    h);
          break;
        case 64:
          prefetch_store(dst + 32);
          convolve_avg_vert_64_dspr2(src, src_stride, dst, dst_stride, filter_y,
                                     h);
          break;
        default:
          aom_convolve8_avg_vert_c(src, src_stride, dst, dst_stride, filter_x,
                                   x_step_q4, filter_y, y_step_q4, w, h);
          break;
      }
    }
  }
  
  void aom_convolve8_avg_dspr2(const uint8_t *src, ptrdiff_t src_stride,
                               uint8_t *dst, ptrdiff_t dst_stride,
                               const int16_t *filter_x, int x_step_q4,
                               const int16_t *filter_y, int y_step_q4, int w,
                               int h) {
    /* Fixed size intermediate buffer places limits on parameters. */
    DECLARE_ALIGNED(32, uint8_t, temp[64 * 135]);
    int32_t intermediate_height = ((h * y_step_q4) >> 4) + 7;
  
    assert(w <= 64);
    assert(h <= 64);
    assert(x_step_q4 == 16);
    assert(y_step_q4 == 16);
  
    if (intermediate_height < h) intermediate_height = h;
  
    aom_convolve8_horiz(src - (src_stride * 3), src_stride, temp, 64, filter_x,
                        x_step_q4, filter_y, y_step_q4, w, intermediate_height);
  
    aom_convolve8_avg_vert(temp + 64 * 3, 64, dst, dst_stride, filter_x,
                           x_step_q4, filter_y, y_step_q4, w, h);
  }
  
  void aom_convolve_avg_dspr2(const uint8_t *src, ptrdiff_t src_stride,
                              uint8_t *dst, ptrdiff_t dst_stride,
                              const int16_t *filter_x, int filter_x_stride,
                              const int16_t *filter_y, int filter_y_stride, int w,
                              int h) {
    int x, y;
    uint32_t tp1, tp2, tn1;
    uint32_t tp3, tp4, tn2;
  
    (void)filter_x;
    (void)filter_x_stride;
    (void)filter_y;
    (void)filter_y_stride;
  
    /* prefetch data to cache memory */
    prefetch_load(src);
    prefetch_load(src + 32);
    prefetch_store(dst);
  
    switch (w) {
      case 4:
        /* 1 word storage */
        for (y = h; y--;) {
          prefetch_load(src + src_stride);
          prefetch_load(src + src_stride + 32);
          prefetch_store(dst + dst_stride);
  
          __asm__ __volatile__(
              "ulw              %[tp1],         0(%[src])      \n\t"
              "ulw              %[tp2],         0(%[dst])      \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "sw               %[tn1],         0(%[dst])      \n\t" /* store */
  
              : [tn1] "=&r"(tn1), [tp1] "=&r"(tp1), [tp2] "=&r"(tp2)
              : [src] "r"(src), [dst] "r"(dst));
  
          src += src_stride;
          dst += dst_stride;
        }
        break;
      case 8:
        /* 2 word storage */
        for (y = h; y--;) {
          prefetch_load(src + src_stride);
          prefetch_load(src + src_stride + 32);
          prefetch_store(dst + dst_stride);
  
          __asm__ __volatile__(
              "ulw              %[tp1],         0(%[src])      \n\t"
              "ulw              %[tp2],         0(%[dst])      \n\t"
              "ulw              %[tp3],         4(%[src])      \n\t"
              "ulw              %[tp4],         4(%[dst])      \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "sw               %[tn1],         0(%[dst])      \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         4(%[dst])      \n\t" /* store */
  
              : [tp1] "=&r"(tp1), [tp2] "=&r"(tp2), [tp3] "=&r"(tp3),
                [tp4] "=&r"(tp4), [tn1] "=&r"(tn1), [tn2] "=&r"(tn2)
              : [src] "r"(src), [dst] "r"(dst));
  
          src += src_stride;
          dst += dst_stride;
        }
        break;
      case 16:
        /* 4 word storage */
        for (y = h; y--;) {
          prefetch_load(src + src_stride);
          prefetch_load(src + src_stride + 32);
          prefetch_store(dst + dst_stride);
  
          __asm__ __volatile__(
              "ulw              %[tp1],         0(%[src])      \n\t"
              "ulw              %[tp2],         0(%[dst])      \n\t"
              "ulw              %[tp3],         4(%[src])      \n\t"
              "ulw              %[tp4],         4(%[dst])      \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         8(%[src])      \n\t"
              "ulw              %[tp2],         8(%[dst])      \n\t"
              "sw               %[tn1],         0(%[dst])      \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         4(%[dst])      \n\t" /* store */
              "ulw              %[tp3],         12(%[src])     \n\t"
              "ulw              %[tp4],         12(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "sw               %[tn1],         8(%[dst])      \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         12(%[dst])     \n\t" /* store */
  
              : [tp1] "=&r"(tp1), [tp2] "=&r"(tp2), [tp3] "=&r"(tp3),
                [tp4] "=&r"(tp4), [tn1] "=&r"(tn1), [tn2] "=&r"(tn2)
              : [src] "r"(src), [dst] "r"(dst));
  
          src += src_stride;
          dst += dst_stride;
        }
        break;
      case 32:
        /* 8 word storage */
        for (y = h; y--;) {
          prefetch_load(src + src_stride);
          prefetch_load(src + src_stride + 32);
          prefetch_store(dst + dst_stride);
  
          __asm__ __volatile__(
              "ulw              %[tp1],         0(%[src])      \n\t"
              "ulw              %[tp2],         0(%[dst])      \n\t"
              "ulw              %[tp3],         4(%[src])      \n\t"
              "ulw              %[tp4],         4(%[dst])      \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         8(%[src])      \n\t"
              "ulw              %[tp2],         8(%[dst])      \n\t"
              "sw               %[tn1],         0(%[dst])      \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         4(%[dst])      \n\t" /* store */
              "ulw              %[tp3],         12(%[src])     \n\t"
              "ulw              %[tp4],         12(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         16(%[src])     \n\t"
              "ulw              %[tp2],         16(%[dst])     \n\t"
              "sw               %[tn1],         8(%[dst])      \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         12(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         20(%[src])     \n\t"
              "ulw              %[tp4],         20(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         24(%[src])     \n\t"
              "ulw              %[tp2],         24(%[dst])     \n\t"
              "sw               %[tn1],         16(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         20(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         28(%[src])     \n\t"
              "ulw              %[tp4],         28(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "sw               %[tn1],         24(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         28(%[dst])     \n\t" /* store */
  
              : [tp1] "=&r"(tp1), [tp2] "=&r"(tp2), [tp3] "=&r"(tp3),
                [tp4] "=&r"(tp4), [tn1] "=&r"(tn1), [tn2] "=&r"(tn2)
              : [src] "r"(src), [dst] "r"(dst));
  
          src += src_stride;
          dst += dst_stride;
        }
        break;
      case 64:
        prefetch_load(src + 64);
        prefetch_store(dst + 32);
  
        /* 16 word storage */
        for (y = h; y--;) {
          prefetch_load(src + src_stride);
          prefetch_load(src + src_stride + 32);
          prefetch_load(src + src_stride + 64);
          prefetch_store(dst + dst_stride);
          prefetch_store(dst + dst_stride + 32);
  
          __asm__ __volatile__(
              "ulw              %[tp1],         0(%[src])      \n\t"
              "ulw              %[tp2],         0(%[dst])      \n\t"
              "ulw              %[tp3],         4(%[src])      \n\t"
              "ulw              %[tp4],         4(%[dst])      \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         8(%[src])      \n\t"
              "ulw              %[tp2],         8(%[dst])      \n\t"
              "sw               %[tn1],         0(%[dst])      \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         4(%[dst])      \n\t" /* store */
              "ulw              %[tp3],         12(%[src])     \n\t"
              "ulw              %[tp4],         12(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         16(%[src])     \n\t"
              "ulw              %[tp2],         16(%[dst])     \n\t"
              "sw               %[tn1],         8(%[dst])      \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         12(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         20(%[src])     \n\t"
              "ulw              %[tp4],         20(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         24(%[src])     \n\t"
              "ulw              %[tp2],         24(%[dst])     \n\t"
              "sw               %[tn1],         16(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         20(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         28(%[src])     \n\t"
              "ulw              %[tp4],         28(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         32(%[src])     \n\t"
              "ulw              %[tp2],         32(%[dst])     \n\t"
              "sw               %[tn1],         24(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         28(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         36(%[src])     \n\t"
              "ulw              %[tp4],         36(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         40(%[src])     \n\t"
              "ulw              %[tp2],         40(%[dst])     \n\t"
              "sw               %[tn1],         32(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         36(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         44(%[src])     \n\t"
              "ulw              %[tp4],         44(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         48(%[src])     \n\t"
              "ulw              %[tp2],         48(%[dst])     \n\t"
              "sw               %[tn1],         40(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         44(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         52(%[src])     \n\t"
              "ulw              %[tp4],         52(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "ulw              %[tp1],         56(%[src])     \n\t"
              "ulw              %[tp2],         56(%[dst])     \n\t"
              "sw               %[tn1],         48(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         52(%[dst])     \n\t" /* store */
              "ulw              %[tp3],         60(%[src])     \n\t"
              "ulw              %[tp4],         60(%[dst])     \n\t"
              "adduh_r.qb       %[tn1], %[tp2], %[tp1]         \n\t" /* average */
              "sw               %[tn1],         56(%[dst])     \n\t" /* store */
              "adduh_r.qb       %[tn2], %[tp3], %[tp4]         \n\t" /* average */
              "sw               %[tn2],         60(%[dst])     \n\t" /* store */
  
              : [tp1] "=&r"(tp1), [tp2] "=&r"(tp2), [tp3] "=&r"(tp3),
                [tp4] "=&r"(tp4), [tn1] "=&r"(tn1), [tn2] "=&r"(tn2)
              : [src] "r"(src), [dst] "r"(dst));
  
          src += src_stride;
          dst += dst_stride;
        }
        break;
      default:
        for (y = h; y > 0; --y) {
          for (x = 0; x < w; ++x) {
            dst[x] = (dst[x] + src[x] + 1) >> 1;
          }
  
          src += src_stride;
          dst += dst_stride;
        }
        break;
    }
  }
  #endif
  