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/*
* Copyright (c) 2020, 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 <arm_neon.h>
#include "aom_dsp/txfm_common.h"
#include "config/av1_rtcd.h"
static void transpose4x4(int16x8_t in[2], int16x4_t out[4]) {
int32x4x2_t b0 =
vtrnq_s32(vreinterpretq_s32_s16(in[0]), vreinterpretq_s32_s16(in[1]));
int16x4x2_t c0 = vtrn_s16(vreinterpret_s16_s32(vget_low_s32(b0.val[0])),
vreinterpret_s16_s32(vget_high_s32(b0.val[0])));
int16x4x2_t c1 = vtrn_s16(vreinterpret_s16_s32(vget_low_s32(b0.val[1])),
vreinterpret_s16_s32(vget_high_s32(b0.val[1])));
out[0] = c0.val[0];
out[1] = c0.val[1];
out[2] = c1.val[0];
out[3] = c1.val[1];
}
void av1_fwht4x4_neon(const int16_t *input, tran_low_t *output, int stride) {
// Load the 4x4 source in transposed form.
int16x4_t a1, b1, c1, d1, e;
a1 = vld1_s16(&input[0]);
b1 = vld1_s16(&input[1 * stride]);
c1 = vld1_s16(&input[2 * stride]);
d1 = vld1_s16(&input[3 * stride]);
// WHT.
// Row transforms.
a1 = vadd_s16(a1, b1);
d1 = vsub_s16(d1, c1);
e = vhsub_s16(a1, d1);
b1 = vsub_s16(e, b1);
c1 = vsub_s16(e, c1);
a1 = vsub_s16(a1, c1);
d1 = vadd_s16(d1, b1);
int16x8_t x[2];
x[0] = vcombine_s16(a1, c1);
x[1] = vcombine_s16(d1, b1);
int16x4_t s[4];
transpose4x4(x, s);
a1 = s[0];
b1 = s[1];
c1 = s[2];
d1 = s[3];
// Row transforms.
a1 = vadd_s16(a1, b1);
d1 = vsub_s16(d1, c1);
e = vhsub_s16(a1, d1);
b1 = vsub_s16(e, b1);
c1 = vsub_s16(e, c1);
a1 = vsub_s16(a1, c1);
d1 = vadd_s16(d1, b1);
vst1q_s32(&output[0], vshll_n_s16(a1, UNIT_QUANT_SHIFT));
vst1q_s32(&output[4], vshll_n_s16(c1, UNIT_QUANT_SHIFT));
vst1q_s32(&output[8], vshll_n_s16(d1, UNIT_QUANT_SHIFT));
vst1q_s32(&output[12], vshll_n_s16(b1, UNIT_QUANT_SHIFT));
}