/*
 *  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>

static const int16_t cospi8sqrt2minus1 = 20091;
static const int16_t sinpi8sqrt2       = 35468;

void vp8_short_idct4x4llm_neon(
        int16_t *input,
        unsigned char *pred_ptr,
        int pred_stride,
        unsigned char *dst_ptr,
        int dst_stride) {
    int i;
    uint32x2_t d6u32 = vdup_n_u32(0);
    uint8x8_t d1u8;
    int16x4_t d2, d3, d4, d5, d10, d11, d12, d13;
    uint16x8_t q1u16;
    int16x8_t q1s16, q2s16, q3s16, q4s16;
    int32x2x2_t v2tmp0, v2tmp1;
    int16x4x2_t v2tmp2, v2tmp3;

    d2 = vld1_s16(input);
    d3 = vld1_s16(input + 4);
    d4 = vld1_s16(input + 8);
    d5 = vld1_s16(input + 12);

    // 1st for loop
    q1s16 = vcombine_s16(d2, d4);  // Swap d3 d4 here
    q2s16 = vcombine_s16(d3, d5);

    q3s16 = vqdmulhq_n_s16(q2s16, sinpi8sqrt2);
    q4s16 = vqdmulhq_n_s16(q2s16, cospi8sqrt2minus1);

    d12 = vqadd_s16(vget_low_s16(q1s16), vget_high_s16(q1s16));  // a1
    d13 = vqsub_s16(vget_low_s16(q1s16), vget_high_s16(q1s16));  // b1

    q3s16 = vshrq_n_s16(q3s16, 1);
    q4s16 = vshrq_n_s16(q4s16, 1);

    q3s16 = vqaddq_s16(q3s16, q2s16);
    q4s16 = vqaddq_s16(q4s16, q2s16);

    d10 = vqsub_s16(vget_low_s16(q3s16), vget_high_s16(q4s16));  // c1
    d11 = vqadd_s16(vget_high_s16(q3s16), vget_low_s16(q4s16));  // d1

    d2 = vqadd_s16(d12, d11);
    d3 = vqadd_s16(d13, d10);
    d4 = vqsub_s16(d13, d10);
    d5 = vqsub_s16(d12, d11);

    v2tmp0 = vtrn_s32(vreinterpret_s32_s16(d2), vreinterpret_s32_s16(d4));
    v2tmp1 = vtrn_s32(vreinterpret_s32_s16(d3), vreinterpret_s32_s16(d5));
    v2tmp2 = vtrn_s16(vreinterpret_s16_s32(v2tmp0.val[0]),
                      vreinterpret_s16_s32(v2tmp1.val[0]));
    v2tmp3 = vtrn_s16(vreinterpret_s16_s32(v2tmp0.val[1]),
                      vreinterpret_s16_s32(v2tmp1.val[1]));

    // 2nd for loop
    q1s16 = vcombine_s16(v2tmp2.val[0], v2tmp3.val[0]);
    q2s16 = vcombine_s16(v2tmp2.val[1], v2tmp3.val[1]);

    q3s16 = vqdmulhq_n_s16(q2s16, sinpi8sqrt2);
    q4s16 = vqdmulhq_n_s16(q2s16, cospi8sqrt2minus1);

    d12 = vqadd_s16(vget_low_s16(q1s16), vget_high_s16(q1s16));  // a1
    d13 = vqsub_s16(vget_low_s16(q1s16), vget_high_s16(q1s16));  // b1

    q3s16 = vshrq_n_s16(q3s16, 1);
    q4s16 = vshrq_n_s16(q4s16, 1);

    q3s16 = vqaddq_s16(q3s16, q2s16);
    q4s16 = vqaddq_s16(q4s16, q2s16);

    d10 = vqsub_s16(vget_low_s16(q3s16), vget_high_s16(q4s16));  // c1
    d11 = vqadd_s16(vget_high_s16(q3s16), vget_low_s16(q4s16));  // d1

    d2 = vqadd_s16(d12, d11);
    d3 = vqadd_s16(d13, d10);
    d4 = vqsub_s16(d13, d10);
    d5 = vqsub_s16(d12, d11);

    d2 = vrshr_n_s16(d2, 3);
    d3 = vrshr_n_s16(d3, 3);
    d4 = vrshr_n_s16(d4, 3);
    d5 = vrshr_n_s16(d5, 3);

    v2tmp0 = vtrn_s32(vreinterpret_s32_s16(d2), vreinterpret_s32_s16(d4));
    v2tmp1 = vtrn_s32(vreinterpret_s32_s16(d3), vreinterpret_s32_s16(d5));
    v2tmp2 = vtrn_s16(vreinterpret_s16_s32(v2tmp0.val[0]),
                      vreinterpret_s16_s32(v2tmp1.val[0]));
    v2tmp3 = vtrn_s16(vreinterpret_s16_s32(v2tmp0.val[1]),
                      vreinterpret_s16_s32(v2tmp1.val[1]));

    q1s16 = vcombine_s16(v2tmp2.val[0], v2tmp2.val[1]);
    q2s16 = vcombine_s16(v2tmp3.val[0], v2tmp3.val[1]);

    // dc_only_idct_add
    for (i = 0; i < 2; i++, q1s16 = q2s16) {
        d6u32 = vld1_lane_u32((const uint32_t *)pred_ptr, d6u32, 0);
        pred_ptr += pred_stride;
        d6u32 = vld1_lane_u32((const uint32_t *)pred_ptr, d6u32, 1);
        pred_ptr += pred_stride;

        q1u16 = vaddw_u8(vreinterpretq_u16_s16(q1s16),
                         vreinterpret_u8_u32(d6u32));
        d1u8 = vqmovun_s16(vreinterpretq_s16_u16(q1u16));

        vst1_lane_u32((uint32_t *)dst_ptr, vreinterpret_u32_u8(d1u8), 0);
        dst_ptr += dst_stride;
        vst1_lane_u32((uint32_t *)dst_ptr, vreinterpret_u32_u8(d1u8), 1);
        dst_ptr += dst_stride;
    }
    return;
}