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      1 /*
      2  *  Copyright (c) 2014 The WebM project authors. All Rights Reserved.
      3  *
      4  *  Use of this source code is governed by a BSD-style license
      5  *  that can be found in the LICENSE file in the root of the source
      6  *  tree. An additional intellectual property rights grant can be found
      7  *  in the file PATENTS.  All contributing project authors may
      8  *  be found in the AUTHORS file in the root of the source tree.
      9  */
     10 
     11 #include <arm_neon.h>
     12 #include "vp8/encoder/block.h"
     13 
     14 static const uint16_t inv_zig_zag[16] = {
     15     1,  2,  6,   7,
     16     3,  5,  8,  13,
     17     4,  9,  12, 14,
     18     10, 11, 15, 16
     19 };
     20 
     21 void vp8_fast_quantize_b_neon(BLOCK *b, BLOCKD *d) {
     22     const int16x8_t one_q = vdupq_n_s16(-1),
     23                     z0 = vld1q_s16(b->coeff),
     24                     z1 = vld1q_s16(b->coeff + 8),
     25                     round0 = vld1q_s16(b->round),
     26                     round1 = vld1q_s16(b->round + 8),
     27                     quant0 = vld1q_s16(b->quant_fast),
     28                     quant1 = vld1q_s16(b->quant_fast + 8),
     29                     dequant0 = vld1q_s16(d->dequant),
     30                     dequant1 = vld1q_s16(d->dequant + 8);
     31     const uint16x8_t zig_zag0 = vld1q_u16(inv_zig_zag),
     32                      zig_zag1 = vld1q_u16(inv_zig_zag + 8);
     33     int16x8_t x0, x1, sz0, sz1, y0, y1;
     34     uint16x8_t eob0, eob1;
     35     uint16x4_t eob_d16;
     36     uint32x2_t eob_d32;
     37     uint32x4_t eob_q32;
     38 
     39     /* sign of z: z >> 15 */
     40     sz0 = vshrq_n_s16(z0, 15);
     41     sz1 = vshrq_n_s16(z1, 15);
     42 
     43     /* x = abs(z) */
     44     x0 = vabsq_s16(z0);
     45     x1 = vabsq_s16(z1);
     46 
     47     /* x += round */
     48     x0 = vaddq_s16(x0, round0);
     49     x1 = vaddq_s16(x1, round1);
     50 
     51     /* y = 2 * (x * quant) >> 16 */
     52     y0 = vqdmulhq_s16(x0, quant0);
     53     y1 = vqdmulhq_s16(x1, quant1);
     54 
     55     /* Compensate for doubling in vqdmulhq */
     56     y0 = vshrq_n_s16(y0, 1);
     57     y1 = vshrq_n_s16(y1, 1);
     58 
     59     /* Restore sign bit */
     60     y0 = veorq_s16(y0, sz0);
     61     y1 = veorq_s16(y1, sz1);
     62     x0 = vsubq_s16(y0, sz0);
     63     x1 = vsubq_s16(y1, sz1);
     64 
     65     /* find non-zero elements */
     66     eob0 = vtstq_s16(x0, one_q);
     67     eob1 = vtstq_s16(x1, one_q);
     68 
     69     /* mask zig zag */
     70     eob0 = vandq_u16(eob0, zig_zag0);
     71     eob1 = vandq_u16(eob1, zig_zag1);
     72 
     73     /* select the largest value */
     74     eob0 = vmaxq_u16(eob0, eob1);
     75     eob_d16 = vmax_u16(vget_low_u16(eob0), vget_high_u16(eob0));
     76     eob_q32 = vmovl_u16(eob_d16);
     77     eob_d32 = vmax_u32(vget_low_u32(eob_q32), vget_high_u32(eob_q32));
     78     eob_d32 = vpmax_u32(eob_d32, eob_d32);
     79 
     80     /* qcoeff = x */
     81     vst1q_s16(d->qcoeff, x0);
     82     vst1q_s16(d->qcoeff + 8, x1);
     83 
     84     /* dqcoeff = x * dequant */
     85     vst1q_s16(d->dqcoeff, vmulq_s16(dequant0, x0));
     86     vst1q_s16(d->dqcoeff + 8, vmulq_s16(dequant1, x1));
     87 
     88     vst1_lane_s8((int8_t *)d->eob, vreinterpret_s8_u32(eob_d32), 0);
     89 }
     90