/*
* Copyright (c) 2023, 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 <assert.h>

#include "aom_convolve8_neon.h"
#include "common_dsp_rtcd.h"
#include "definitions.h"
#include "filter.h"
#include "mem_neon.h"
#include "transpose_neon.h"

static inline void convolve8_horiz_6tap_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst,
                                             ptrdiff_t dst_stride, const int16_t *filter_x, int w, int h) {
    // All filter values are even so halve them to reduce intermediate precision
    // requirements.
    const int16x8_t filter = vshrq_n_s16(vld1q_s16(filter_x), 1);

    if (h == 4) {
        uint8x8_t t0, t1, t2, t3;
        load_u8_8x4(src, src_stride, &t0, &t1, &t2, &t3);
        transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);

        int16x4_t s0 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
        int16x4_t s1 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
        int16x4_t s2 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
        int16x4_t s3 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
        int16x4_t s4 = vget_high_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));

        src += 5;

        do {
            load_u8_8x4(src, src_stride, &t0, &t1, &t2, &t3);
            transpose_elems_inplace_u8_8x4(&t0, &t1, &t2, &t3);

            int16x4_t s5 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
            int16x4_t s6 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
            int16x4_t s7 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
            int16x4_t s8 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));

            int16x4_t d0 = convolve6_4(s0, s1, s2, s3, s4, s5, filter);
            int16x4_t d1 = convolve6_4(s1, s2, s3, s4, s5, s6, filter);
            int16x4_t d2 = convolve6_4(s2, s3, s4, s5, s6, s7, filter);
            int16x4_t d3 = convolve6_4(s3, s4, s5, s6, s7, s8, filter);

            // We halved the filter values so -1 from right shift.
            uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
            uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS - 1);

            transpose_elems_inplace_u8_4x4(&d01, &d23);

            store_u8x4_strided_x2(dst + 0 * dst_stride, 2 * dst_stride, d01);
            store_u8x4_strided_x2(dst + 1 * dst_stride, 2 * dst_stride, d23);

            s0 = s4;
            s1 = s5;
            s2 = s6;
            s3 = s7;
            s4 = s8;

            src += 4;
            dst += 4;
            w -= 4;
        } while (w != 0);
    } else {
        if (w == 4) {
            do {
                uint8x8_t t0, t1, t2, t3, t4, t5, t6, t7;
                load_u8_8x8(src, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
                transpose_elems_inplace_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);

                int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
                int16x8_t s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
                int16x8_t s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
                int16x8_t s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
                int16x8_t s4 = vreinterpretq_s16_u16(vmovl_u8(t4));
                int16x8_t s5 = vreinterpretq_s16_u16(vmovl_u8(t5));

                load_u8_8x8(src + 6, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
                transpose_elems_u8_4x8(t0, t1, t2, t3, t4, t5, t6, t7, &t0, &t1, &t2, &t3);

                int16x8_t s6 = vreinterpretq_s16_u16(vmovl_u8(t0));
                int16x8_t s7 = vreinterpretq_s16_u16(vmovl_u8(t1));
                int16x8_t s8 = vreinterpretq_s16_u16(vmovl_u8(t2));

                uint8x8_t d0 = convolve6_8(s0, s1, s2, s3, s4, s5, filter);
                uint8x8_t d1 = convolve6_8(s1, s2, s3, s4, s5, s6, filter);
                uint8x8_t d2 = convolve6_8(s2, s3, s4, s5, s6, s7, filter);
                uint8x8_t d3 = convolve6_8(s3, s4, s5, s6, s7, s8, filter);

                transpose_elems_inplace_u8_8x4(&d0, &d1, &d2, &d3);

                store_u8x4_strided_x2(dst + 0 * dst_stride, 4 * dst_stride, d0);
                store_u8x4_strided_x2(dst + 1 * dst_stride, 4 * dst_stride, d1);
                store_u8x4_strided_x2(dst + 2 * dst_stride, 4 * dst_stride, d2);
                store_u8x4_strided_x2(dst + 3 * dst_stride, 4 * dst_stride, d3);

                src += 8 * src_stride;
                dst += 8 * dst_stride;
                h -= 8;
            } while (h > 0);
        } else {
            do {
                int            width = w;
                const uint8_t *s     = src;
                uint8_t       *d     = dst;

                uint8x8_t t0, t1, t2, t3, t4, t5, t6, t7;
                load_u8_8x8(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
                transpose_elems_inplace_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);

                int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
                int16x8_t s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
                int16x8_t s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
                int16x8_t s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
                int16x8_t s4 = vreinterpretq_s16_u16(vmovl_u8(t4));

                s += 5;

                do {
                    load_u8_8x8(s, src_stride, &t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);
                    transpose_elems_inplace_u8_8x8(&t0, &t1, &t2, &t3, &t4, &t5, &t6, &t7);

                    int16x8_t s5  = vreinterpretq_s16_u16(vmovl_u8(t0));
                    int16x8_t s6  = vreinterpretq_s16_u16(vmovl_u8(t1));
                    int16x8_t s7  = vreinterpretq_s16_u16(vmovl_u8(t2));
                    int16x8_t s8  = vreinterpretq_s16_u16(vmovl_u8(t3));
                    int16x8_t s9  = vreinterpretq_s16_u16(vmovl_u8(t4));
                    int16x8_t s10 = vreinterpretq_s16_u16(vmovl_u8(t5));
                    int16x8_t s11 = vreinterpretq_s16_u16(vmovl_u8(t6));
                    int16x8_t s12 = vreinterpretq_s16_u16(vmovl_u8(t7));

                    uint8x8_t d0 = convolve6_8(s0, s1, s2, s3, s4, s5, filter);
                    uint8x8_t d1 = convolve6_8(s1, s2, s3, s4, s5, s6, filter);
                    uint8x8_t d2 = convolve6_8(s2, s3, s4, s5, s6, s7, filter);
                    uint8x8_t d3 = convolve6_8(s3, s4, s5, s6, s7, s8, filter);
                    uint8x8_t d4 = convolve6_8(s4, s5, s6, s7, s8, s9, filter);
                    uint8x8_t d5 = convolve6_8(s5, s6, s7, s8, s9, s10, filter);
                    uint8x8_t d6 = convolve6_8(s6, s7, s8, s9, s10, s11, filter);
                    uint8x8_t d7 = convolve6_8(s7, s8, s9, s10, s11, s12, filter);

                    transpose_elems_inplace_u8_8x8(&d0, &d1, &d2, &d3, &d4, &d5, &d6, &d7);

                    store_u8_8x8(d, dst_stride, d0, d1, d2, d3, d4, d5, d6, d7);

                    s0 = s8;
                    s1 = s9;
                    s2 = s10;
                    s3 = s11;
                    s4 = s12;

                    s += 8;
                    d += 8;
                    width -= 8;
                } while (width != 0);
                src += 8 * src_stride;
                dst += 8 * dst_stride;
                h -= 8;
            } while (h > 0);
        }
    }
}

static inline void convolve8_horiz_4tap_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst,
                                             ptrdiff_t dst_stride, const int16_t *filter_x, int w, int h) {
    // All filter values are even, halve to reduce intermediate precision
    // requirements.
    const int16x4_t filter = vshr_n_s16(vld1_s16(filter_x + 2), 1);

    if (w == 4) {
        do {
            uint8x8_t t01[4];

            t01[0] = load_u8_4x2(src + 0, (int)src_stride);
            t01[1] = load_u8_4x2(src + 1, (int)src_stride);
            t01[2] = load_u8_4x2(src + 2, (int)src_stride);
            t01[3] = load_u8_4x2(src + 3, (int)src_stride);

            int16x8_t s01[4];
            s01[0] = vreinterpretq_s16_u16(vmovl_u8(t01[0]));
            s01[1] = vreinterpretq_s16_u16(vmovl_u8(t01[1]));
            s01[2] = vreinterpretq_s16_u16(vmovl_u8(t01[2]));
            s01[3] = vreinterpretq_s16_u16(vmovl_u8(t01[3]));

            uint8x8_t d01 = convolve4_8(s01[0], s01[1], s01[2], s01[3], filter);

            store_u8x4_strided_x2(dst + 0 * dst_stride, dst_stride, d01);

            src += 2 * src_stride;
            dst += 2 * dst_stride;
            h -= 2;
        } while (h > 0);
    } else {
        do {
            int            width = w;
            const uint8_t *s     = src;
            uint8_t       *d     = dst;

            do {
                uint8x8_t t0[4], t1[4];
                load_u8_8x4(s + 0 * src_stride, 1, &t0[0], &t0[1], &t0[2], &t0[3]);
                load_u8_8x4(s + 1 * src_stride, 1, &t1[0], &t1[1], &t1[2], &t1[3]);

                int16x8_t s0[4], s1[4];
                s0[0] = vreinterpretq_s16_u16(vmovl_u8(t0[0]));
                s0[1] = vreinterpretq_s16_u16(vmovl_u8(t0[1]));
                s0[2] = vreinterpretq_s16_u16(vmovl_u8(t0[2]));
                s0[3] = vreinterpretq_s16_u16(vmovl_u8(t0[3]));

                s1[0] = vreinterpretq_s16_u16(vmovl_u8(t1[0]));
                s1[1] = vreinterpretq_s16_u16(vmovl_u8(t1[1]));
                s1[2] = vreinterpretq_s16_u16(vmovl_u8(t1[2]));
                s1[3] = vreinterpretq_s16_u16(vmovl_u8(t1[3]));

                uint8x8_t d0 = convolve4_8(s0[0], s0[1], s0[2], s0[3], filter);
                uint8x8_t d1 = convolve4_8(s1[0], s1[1], s1[2], s1[3], filter);

                store_u8_8x2(d, dst_stride, d0, d1);

                s += 8;
                d += 8;
                width -= 8;
            } while (width != 0);
            src += 2 * src_stride;
            dst += 2 * dst_stride;
            h -= 2;
        } while (h > 0);
    }
}

void svt_aom_convolve8_horiz_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride,
                                  const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w,
                                  int h) {
    assert((intptr_t)dst % 4 == 0);
    assert(dst_stride % 4 == 0);

    (void)x_step_q4;
    (void)filter_y;
    (void)y_step_q4;

    src -= (SUBPEL_TAPS / 2) - 1;

    int filter_taps = get_filter_taps_convolve8(filter_x);

    if (filter_taps == 2) {
        convolve8_horiz_2tap_neon(src + 3, src_stride, dst, dst_stride, filter_x, w, h);
    } else if (filter_taps == 4) {
        convolve8_horiz_4tap_neon(src + 2, src_stride, dst, dst_stride, filter_x, w, h);
    } else {
        convolve8_horiz_6tap_neon(src + 1, src_stride, dst, dst_stride, filter_x, w, h);
    }
}

static inline void convolve8_vert_6tap_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst,
                                            ptrdiff_t dst_stride, const int16_t *filter_y, int w, int h) {
    // All filter values are even so halve them to reduce intermediate precision
    // requirements.
    const int16x8_t filter = vshrq_n_s16(vld1q_s16(filter_y), 1);

    if (w == 4) {
        uint8x8_t t0, t1, t2, t3, t4;
        load_u8_8x5(src, src_stride, &t0, &t1, &t2, &t3, &t4);

        int16x4_t s0 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
        int16x4_t s1 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
        int16x4_t s2 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
        int16x4_t s3 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));
        int16x4_t s4 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t4)));

        src += 5 * src_stride;

        do {
            load_u8_8x4(src, src_stride, &t0, &t1, &t2, &t3);

            int16x4_t s5 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t0)));
            int16x4_t s6 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t1)));
            int16x4_t s7 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t2)));
            int16x4_t s8 = vget_low_s16(vreinterpretq_s16_u16(vmovl_u8(t3)));

            int16x4_t d0 = convolve6_4(s0, s1, s2, s3, s4, s5, filter);
            int16x4_t d1 = convolve6_4(s1, s2, s3, s4, s5, s6, filter);
            int16x4_t d2 = convolve6_4(s2, s3, s4, s5, s6, s7, filter);
            int16x4_t d3 = convolve6_4(s3, s4, s5, s6, s7, s8, filter);

            // We halved the filter values so -1 from right shift.
            uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
            uint8x8_t d23 = vqrshrun_n_s16(vcombine_s16(d2, d3), FILTER_BITS - 1);

            store_u8x4_strided_x2(dst + 0 * dst_stride, dst_stride, d01);
            store_u8x4_strided_x2(dst + 2 * dst_stride, dst_stride, d23);

            s0 = s4;
            s1 = s5;
            s2 = s6;
            s3 = s7;
            s4 = s8;

            src += 4 * src_stride;
            dst += 4 * dst_stride;
            h -= 4;
        } while (h != 0);
    } else {
        do {
            uint8x8_t t0, t1, t2, t3, t4;
            load_u8_8x5(src, src_stride, &t0, &t1, &t2, &t3, &t4);

            int16x8_t s0 = vreinterpretq_s16_u16(vmovl_u8(t0));
            int16x8_t s1 = vreinterpretq_s16_u16(vmovl_u8(t1));
            int16x8_t s2 = vreinterpretq_s16_u16(vmovl_u8(t2));
            int16x8_t s3 = vreinterpretq_s16_u16(vmovl_u8(t3));
            int16x8_t s4 = vreinterpretq_s16_u16(vmovl_u8(t4));

            int            height = h;
            const uint8_t *s      = src + 5 * src_stride;
            uint8_t       *d      = dst;

            do {
                load_u8_8x4(s, src_stride, &t0, &t1, &t2, &t3);

                int16x8_t s5 = vreinterpretq_s16_u16(vmovl_u8(t0));
                int16x8_t s6 = vreinterpretq_s16_u16(vmovl_u8(t1));
                int16x8_t s7 = vreinterpretq_s16_u16(vmovl_u8(t2));
                int16x8_t s8 = vreinterpretq_s16_u16(vmovl_u8(t3));

                uint8x8_t d0 = convolve6_8(s0, s1, s2, s3, s4, s5, filter);
                uint8x8_t d1 = convolve6_8(s1, s2, s3, s4, s5, s6, filter);
                uint8x8_t d2 = convolve6_8(s2, s3, s4, s5, s6, s7, filter);
                uint8x8_t d3 = convolve6_8(s3, s4, s5, s6, s7, s8, filter);

                store_u8_8x4(d, dst_stride, d0, d1, d2, d3);

                s0 = s4;
                s1 = s5;
                s2 = s6;
                s3 = s7;
                s4 = s8;

                s += 4 * src_stride;
                d += 4 * dst_stride;
                height -= 4;
            } while (height != 0);
            src += 8;
            dst += 8;
            w -= 8;
        } while (w != 0);
    }
}

void svt_aom_convolve8_vert_neon(const uint8_t *src, ptrdiff_t src_stride, uint8_t *dst, ptrdiff_t dst_stride,
                                 const int16_t *filter_x, int x_step_q4, const int16_t *filter_y, int y_step_q4, int w,
                                 int h) {
    assert((intptr_t)dst % 4 == 0);
    assert(dst_stride % 4 == 0);

    (void)filter_x;
    (void)x_step_q4;
    (void)y_step_q4;

    src -= ((SUBPEL_TAPS / 2) - 1) * src_stride;

    int filter_taps = get_filter_taps_convolve8(filter_y);

    if (filter_taps == 2) {
        convolve8_vert_2tap_neon(src + 3 * src_stride, src_stride, dst, dst_stride, filter_y, w, h);
    } else if (filter_taps == 4) {
        convolve8_vert_4tap_neon(src + 2 * src_stride, src_stride, dst, dst_stride, filter_y, w, h);
    } else {
        assert(filter_taps == 6);
        convolve8_vert_6tap_neon(src + 1 * src_stride, src_stride, dst, dst_stride, filter_y, w, h);
    }
}
