/*
 *  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       = 17734;
// because the lowest bit in 0x8a8c is 0, we can pre-shift this

void idct_dequant_full_2x_neon(
        int16_t *q,
        int16_t *dq,
        unsigned char *dst,
        int stride) {
    unsigned char *dst0, *dst1;
    int32x2_t d28, d29, d30, d31;
    int16x8_t q0, q1, q2, q3, q4, q5, q6, q7, q8, q9, q10, q11;
    int16x8_t qEmpty = vdupq_n_s16(0);
    int32x4x2_t q2tmp0, q2tmp1;
    int16x8x2_t q2tmp2, q2tmp3;
    int16x4_t dLow0, dLow1, dHigh0, dHigh1;

    d28 = d29 = d30 = d31 = vdup_n_s32(0);

    // load dq
    q0 = vld1q_s16(dq);
    dq += 8;
    q1 = vld1q_s16(dq);

    // load q
    q2 = vld1q_s16(q);
    vst1q_s16(q, qEmpty);
    q += 8;
    q3 = vld1q_s16(q);
    vst1q_s16(q, qEmpty);
    q += 8;
    q4 = vld1q_s16(q);
    vst1q_s16(q, qEmpty);
    q += 8;
    q5 = vld1q_s16(q);
    vst1q_s16(q, qEmpty);

    // load src from dst
    dst0 = dst;
    dst1 = dst + 4;
    d28 = vld1_lane_s32((const int32_t *)dst0, d28, 0);
    dst0 += stride;
    d28 = vld1_lane_s32((const int32_t *)dst1, d28, 1);
    dst1 += stride;
    d29 = vld1_lane_s32((const int32_t *)dst0, d29, 0);
    dst0 += stride;
    d29 = vld1_lane_s32((const int32_t *)dst1, d29, 1);
    dst1 += stride;

    d30 = vld1_lane_s32((const int32_t *)dst0, d30, 0);
    dst0 += stride;
    d30 = vld1_lane_s32((const int32_t *)dst1, d30, 1);
    dst1 += stride;
    d31 = vld1_lane_s32((const int32_t *)dst0, d31, 0);
    d31 = vld1_lane_s32((const int32_t *)dst1, d31, 1);

    q2 = vmulq_s16(q2, q0);
    q3 = vmulq_s16(q3, q1);
    q4 = vmulq_s16(q4, q0);
    q5 = vmulq_s16(q5, q1);

    // vswp
    dLow0 = vget_low_s16(q2);
    dHigh0 = vget_high_s16(q2);
    dLow1 = vget_low_s16(q4);
    dHigh1 = vget_high_s16(q4);
    q2 = vcombine_s16(dLow0, dLow1);
    q4 = vcombine_s16(dHigh0, dHigh1);

    dLow0 = vget_low_s16(q3);
    dHigh0 = vget_high_s16(q3);
    dLow1 = vget_low_s16(q5);
    dHigh1 = vget_high_s16(q5);
    q3 = vcombine_s16(dLow0, dLow1);
    q5 = vcombine_s16(dHigh0, dHigh1);

    q6 = vqdmulhq_n_s16(q4, sinpi8sqrt2);
    q7 = vqdmulhq_n_s16(q5, sinpi8sqrt2);
    q8 = vqdmulhq_n_s16(q4, cospi8sqrt2minus1);
    q9 = vqdmulhq_n_s16(q5, cospi8sqrt2minus1);

    q10 = vqaddq_s16(q2, q3);
    q11 = vqsubq_s16(q2, q3);

    q8 = vshrq_n_s16(q8, 1);
    q9 = vshrq_n_s16(q9, 1);

    q4 = vqaddq_s16(q4, q8);
    q5 = vqaddq_s16(q5, q9);

    q2 = vqsubq_s16(q6, q5);
    q3 = vqaddq_s16(q7, q4);

    q4 = vqaddq_s16(q10, q3);
    q5 = vqaddq_s16(q11, q2);
    q6 = vqsubq_s16(q11, q2);
    q7 = vqsubq_s16(q10, q3);

    q2tmp0 = vtrnq_s32(vreinterpretq_s32_s16(q4), vreinterpretq_s32_s16(q6));
    q2tmp1 = vtrnq_s32(vreinterpretq_s32_s16(q5), vreinterpretq_s32_s16(q7));
    q2tmp2 = vtrnq_s16(vreinterpretq_s16_s32(q2tmp0.val[0]),
                       vreinterpretq_s16_s32(q2tmp1.val[0]));
    q2tmp3 = vtrnq_s16(vreinterpretq_s16_s32(q2tmp0.val[1]),
                       vreinterpretq_s16_s32(q2tmp1.val[1]));

    // loop 2
    q8  = vqdmulhq_n_s16(q2tmp2.val[1], sinpi8sqrt2);
    q9  = vqdmulhq_n_s16(q2tmp3.val[1], sinpi8sqrt2);
    q10 = vqdmulhq_n_s16(q2tmp2.val[1], cospi8sqrt2minus1);
    q11 = vqdmulhq_n_s16(q2tmp3.val[1], cospi8sqrt2minus1);

    q2 = vqaddq_s16(q2tmp2.val[0], q2tmp3.val[0]);
    q3 = vqsubq_s16(q2tmp2.val[0], q2tmp3.val[0]);

    q10 = vshrq_n_s16(q10, 1);
    q11 = vshrq_n_s16(q11, 1);

    q10 = vqaddq_s16(q2tmp2.val[1], q10);
    q11 = vqaddq_s16(q2tmp3.val[1], q11);

    q8 = vqsubq_s16(q8, q11);
    q9 = vqaddq_s16(q9, q10);

    q4 = vqaddq_s16(q2, q9);
    q5 = vqaddq_s16(q3, q8);
    q6 = vqsubq_s16(q3, q8);
    q7 = vqsubq_s16(q2, q9);

    q4 = vrshrq_n_s16(q4, 3);
    q5 = vrshrq_n_s16(q5, 3);
    q6 = vrshrq_n_s16(q6, 3);
    q7 = vrshrq_n_s16(q7, 3);

    q2tmp0 = vtrnq_s32(vreinterpretq_s32_s16(q4), vreinterpretq_s32_s16(q6));
    q2tmp1 = vtrnq_s32(vreinterpretq_s32_s16(q5), vreinterpretq_s32_s16(q7));
    q2tmp2 = vtrnq_s16(vreinterpretq_s16_s32(q2tmp0.val[0]),
                       vreinterpretq_s16_s32(q2tmp1.val[0]));
    q2tmp3 = vtrnq_s16(vreinterpretq_s16_s32(q2tmp0.val[1]),
                       vreinterpretq_s16_s32(q2tmp1.val[1]));

    q4 = vreinterpretq_s16_u16(vaddw_u8(vreinterpretq_u16_s16(q2tmp2.val[0]),
                                          vreinterpret_u8_s32(d28)));
    q5 = vreinterpretq_s16_u16(vaddw_u8(vreinterpretq_u16_s16(q2tmp2.val[1]),
                                          vreinterpret_u8_s32(d29)));
    q6 = vreinterpretq_s16_u16(vaddw_u8(vreinterpretq_u16_s16(q2tmp3.val[0]),
                                          vreinterpret_u8_s32(d30)));
    q7 = vreinterpretq_s16_u16(vaddw_u8(vreinterpretq_u16_s16(q2tmp3.val[1]),
                                          vreinterpret_u8_s32(d31)));

    d28 = vreinterpret_s32_u8(vqmovun_s16(q4));
    d29 = vreinterpret_s32_u8(vqmovun_s16(q5));
    d30 = vreinterpret_s32_u8(vqmovun_s16(q6));
    d31 = vreinterpret_s32_u8(vqmovun_s16(q7));

    dst0 = dst;
    dst1 = dst + 4;
    vst1_lane_s32((int32_t *)dst0, d28, 0);
    dst0 += stride;
    vst1_lane_s32((int32_t *)dst1, d28, 1);
    dst1 += stride;
    vst1_lane_s32((int32_t *)dst0, d29, 0);
    dst0 += stride;
    vst1_lane_s32((int32_t *)dst1, d29, 1);
    dst1 += stride;

    vst1_lane_s32((int32_t *)dst0, d30, 0);
    dst0 += stride;
    vst1_lane_s32((int32_t *)dst1, d30, 1);
    dst1 += stride;
    vst1_lane_s32((int32_t *)dst0, d31, 0);
    vst1_lane_s32((int32_t *)dst1, d31, 1);
    return;
}