ref: c42517568d7997eb1f7534330da8aa1427ecdadc
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;
const int16x4_t cospis = vld1_s16(kCospi);
uint8x8_t dest01_u8;
uint32x2_t dest32_u32 = vdup_n_u32(0);
int16x8_t a0, a1;
uint8x8_t d01, d32;
uint16x8_t d01_u16, d32_u16;
assert(!((intptr_t)dest % sizeof(uint32_t)));
assert(!(stride % sizeof(uint32_t)));
// Rows
a0 = load_tran_low_to_s16q(input);
a1 = load_tran_low_to_s16q(input + 8);
idct4x4_16_kernel_bd8(cospis, &a0, &a1);
// Columns
a1 = vcombine_s16(vget_high_s16(a1), vget_low_s16(a1));
idct4x4_16_kernel_bd8(cospis, &a0, &a1);
a0 = vrshrq_n_s16(a0, 4);
a1 = vrshrq_n_s16(a1, 4);
dest01_u8 = load_u8(dst, stride);
dst += 2 * stride;
// The elements are loaded in reverse order.
dest32_u32 = vld1_lane_u32((const uint32_t *)dst, dest32_u32, 1);
dst += stride;
dest32_u32 = vld1_lane_u32((const uint32_t *)dst, dest32_u32, 0);
d01_u16 = vaddw_u8(vreinterpretq_u16_s16(a0), dest01_u8);
d32_u16 =
vaddw_u8(vreinterpretq_u16_s16(a1), vreinterpret_u8_u32(dest32_u32));
d01 = vqmovun_s16(vreinterpretq_s16_u16(d01_u16));
d32 = vqmovun_s16(vreinterpretq_s16_u16(d32_u16));
store_u8(dest, stride, d01);
dest += 2 * stride;
// The elements are stored in reverse order.
vst1_lane_u32((uint32_t *)dest, vreinterpret_u32_u8(d32), 1);
dest += stride;
vst1_lane_u32((uint32_t *)dest, vreinterpret_u32_u8(d32), 0);
}