ref: 4b402746cad6f9dbebbb3c3b79a2da098385d46f
dir: /vp8/encoder/arm/neon/fastquantizeb_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 "vp8/encoder/block.h"
static const uint16_t inv_zig_zag[16] = { 1, 2, 6, 7, 3, 5, 8, 13,
4, 9, 12, 14, 10, 11, 15, 16 };
void vp8_fast_quantize_b_neon(BLOCK *b, BLOCKD *d) {
const int16x8_t one_q = vdupq_n_s16(-1), z0 = vld1q_s16(b->coeff),
z1 = vld1q_s16(b->coeff + 8), round0 = vld1q_s16(b->round),
round1 = vld1q_s16(b->round + 8),
quant0 = vld1q_s16(b->quant_fast),
quant1 = vld1q_s16(b->quant_fast + 8),
dequant0 = vld1q_s16(d->dequant),
dequant1 = vld1q_s16(d->dequant + 8);
const uint16x8_t zig_zag0 = vld1q_u16(inv_zig_zag),
zig_zag1 = vld1q_u16(inv_zig_zag + 8);
int16x8_t x0, x1, sz0, sz1, y0, y1;
uint16x8_t eob0, eob1;
uint16x4_t eob_d16;
uint32x2_t eob_d32;
uint32x4_t eob_q32;
/* sign of z: z >> 15 */
sz0 = vshrq_n_s16(z0, 15);
sz1 = vshrq_n_s16(z1, 15);
/* x = abs(z) */
x0 = vabsq_s16(z0);
x1 = vabsq_s16(z1);
/* x += round */
x0 = vaddq_s16(x0, round0);
x1 = vaddq_s16(x1, round1);
/* y = 2 * (x * quant) >> 16 */
y0 = vqdmulhq_s16(x0, quant0);
y1 = vqdmulhq_s16(x1, quant1);
/* Compensate for doubling in vqdmulhq */
y0 = vshrq_n_s16(y0, 1);
y1 = vshrq_n_s16(y1, 1);
/* Restore sign bit */
y0 = veorq_s16(y0, sz0);
y1 = veorq_s16(y1, sz1);
x0 = vsubq_s16(y0, sz0);
x1 = vsubq_s16(y1, sz1);
/* find non-zero elements */
eob0 = vtstq_s16(x0, one_q);
eob1 = vtstq_s16(x1, one_q);
/* mask zig zag */
eob0 = vandq_u16(eob0, zig_zag0);
eob1 = vandq_u16(eob1, zig_zag1);
/* select the largest value */
eob0 = vmaxq_u16(eob0, eob1);
eob_d16 = vmax_u16(vget_low_u16(eob0), vget_high_u16(eob0));
eob_q32 = vmovl_u16(eob_d16);
eob_d32 = vmax_u32(vget_low_u32(eob_q32), vget_high_u32(eob_q32));
eob_d32 = vpmax_u32(eob_d32, eob_d32);
/* qcoeff = x */
vst1q_s16(d->qcoeff, x0);
vst1q_s16(d->qcoeff + 8, x1);
/* dqcoeff = x * dequant */
vst1q_s16(d->dqcoeff, vmulq_s16(dequant0, x0));
vst1q_s16(d->dqcoeff + 8, vmulq_s16(dequant1, x1));
vst1_lane_s8((int8_t *)d->eob, vreinterpret_s8_u32(eob_d32), 0);
}