ref: bb407a27b2e32f89f0e9eeee2bcd0aa9d5cfea3f
dir: /vpx_dsp/arm/vpx_convolve_neon.c/
/*
* Copyright (c) 2013 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 <assert.h>
#include "./vpx_dsp_rtcd.h"
#include "vpx_dsp/vpx_dsp_common.h"
#include "vpx_ports/mem.h"
void vpx_convolve8_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst,
ptrdiff_t dst_stride, const InterpKernel *filter,
int x0_q4, int x_step_q4, int y0_q4, int y_step_q4,
int w, int h) {
/* Given our constraints: w <= 64, h <= 64, taps == 8 we can reduce the
* maximum buffer size to 64 * 64 + 7 (+ 1 to make it divisible by 4).
*/
uint8_t temp[64 * 72];
// Account for the vertical phase needing 3 lines prior and 4 lines post
// (+ 1 to make it divisible by 4).
const int intermediate_height = h + 8;
assert(y_step_q4 == 16);
assert(x_step_q4 == 16);
/* Filter starting 3 lines back. The neon implementation will ignore the given
* height and filter a multiple of 4 lines. Since this goes in to the temp
* buffer which has lots of extra room and is subsequently discarded this is
* safe if somewhat less than ideal. */
vpx_convolve8_horiz_neon(src - src_stride * 3, src_stride, temp, w, filter,
x0_q4, x_step_q4, y0_q4, y_step_q4, w,
intermediate_height);
/* Step into the temp buffer 3 lines to get the actual frame data */
vpx_convolve8_vert_neon(temp + w * 3, w, dst, dst_stride, filter, x0_q4,
x_step_q4, y0_q4, y_step_q4, w, h);
}
void vpx_convolve8_avg_neon(const uint8_t *src, ptrdiff_t src_stride,
uint8_t *dst, ptrdiff_t dst_stride,
const InterpKernel *filter, int x0_q4,
int x_step_q4, int y0_q4, int y_step_q4, int w,
int h) {
uint8_t temp[64 * 72];
const int intermediate_height = h + 8;
assert(y_step_q4 == 16);
assert(x_step_q4 == 16);
/* This implementation has the same issues as above. In addition, we only want
* to average the values after both passes.
*/
vpx_convolve8_horiz_neon(src - src_stride * 3, src_stride, temp, w, filter,
x0_q4, x_step_q4, y0_q4, y_step_q4, w,
intermediate_height);
vpx_convolve8_avg_vert_neon(temp + w * 3, w, dst, dst_stride, filter, x0_q4,
x_step_q4, y0_q4, y_step_q4, w, h);
}