shithub: libvpx

ref: 4baffb97e35030d0d3a4c27bfb255af1c3e7c6f3
dir: /vpx_dsp/arm/idct4x4_add_neon.c/

/*
 *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
 *
 *  Use of this source code is governed by a BSD-style license
 *  that can be found in the LICENSE 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.
 */

#include <arm_neon.h>
#include <assert.h>

#include "./vpx_dsp_rtcd.h"
#include "vpx_dsp/arm/idct_neon.h"
#include "vpx_dsp/arm/mem_neon.h"
#include "vpx_dsp/txfm_common.h"

void vpx_idct4x4_16_add_neon(const tran_low_t *input, uint8_t *dest,
                             int stride) {
  const uint8_t *dst = dest;
  uint32x2_t s32 = vdup_n_u32(0);
  int16x8_t a[2];
  uint8x8_t s, d[2];
  uint16x8_t sum[2];

  assert(!((intptr_t)dest % sizeof(uint32_t)));
  assert(!(stride % sizeof(uint32_t)));

  // Rows
  a[0] = load_tran_low_to_s16q(input);
  a[1] = load_tran_low_to_s16q(input + 8);
  transpose_idct4x4_16_bd8(a);

  // Columns
  a[1] = vcombine_s16(vget_high_s16(a[1]), vget_low_s16(a[1]));
  transpose_idct4x4_16_bd8(a);
  a[0] = vrshrq_n_s16(a[0], 4);
  a[1] = vrshrq_n_s16(a[1], 4);

  s = load_u8(dst, stride);
  dst += 2 * stride;
  // The elements are loaded in reverse order.
  s32 = vld1_lane_u32((const uint32_t *)dst, s32, 1);
  dst += stride;
  s32 = vld1_lane_u32((const uint32_t *)dst, s32, 0);

  sum[0] = vaddw_u8(vreinterpretq_u16_s16(a[0]), s);
  sum[1] = vaddw_u8(vreinterpretq_u16_s16(a[1]), vreinterpret_u8_u32(s32));
  d[0] = vqmovun_s16(vreinterpretq_s16_u16(sum[0]));
  d[1] = vqmovun_s16(vreinterpretq_s16_u16(sum[1]));

  store_u8(dest, stride, d[0]);
  dest += 2 * stride;
  // The elements are stored in reverse order.
  vst1_lane_u32((uint32_t *)dest, vreinterpret_u32_u8(d[1]), 1);
  dest += stride;
  vst1_lane_u32((uint32_t *)dest, vreinterpret_u32_u8(d[1]), 0);
}