pic-scale 0.7.5

/*
 * Copyright (c) Radzivon Bartoshyk. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification,
 * are permitted provided that the following conditions are met:
 *
 * 1.  Redistributions of source code must retain the above copyright notice, this
 * list of conditions and the following disclaimer.
 *
 * 2.  Redistributions in binary form must reproduce the above copyright notice,
 * this list of conditions and the following disclaimer in the documentation
 * and/or other materials provided with the distribution.
 *
 * 3.  Neither the name of the copyright holder nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
 * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
use crate::filter_weights::FilterBounds;
use crate::support::{PRECISION, ROUNDING_CONST};
#[cfg(target_arch = "x86")]
use std::arch::x86::*;
#[cfg(target_arch = "x86_64")]
use std::arch::x86_64::*;

#[inline(always)]
/// This is fixed point path for bit-depth's lower or equal to 12
pub(crate) fn convolve_column_lb_sse_u16(
    _: usize,
    bounds: &FilterBounds,
    src: &[u16],
    dst: &mut [u16],
    src_stride: usize,
    weight: &[i16],
    bit_depth: u32,
) {
    unsafe {
        convolve_column_lb_u16_impl(bounds, src, dst, src_stride, weight, bit_depth);
    }
}

#[target_feature(enable = "sse4.1")]
fn convolve_column_lb_u16_impl(
    bounds: &FilterBounds,
    src: &[u16],
    dst: &mut [u16],
    src_stride: usize,
    weight: &[i16],
    bit_depth: u32,
) {
    unsafe {
        assert!((1..=16).contains(&bit_depth));
        let max_colors = (1 << bit_depth) - 1;
        let mut cx = 0usize;

        let zeros = _mm_setzero_si128();
        let initial_store = _mm_set1_epi32(ROUNDING_CONST);

        let v_max_colors = _mm_set1_epi16(max_colors);

        let v_px = cx;

        let iter16 = dst.chunks_exact_mut(16);

        let weights = &weight[..bounds.size];

        for (x, dst) in iter16.enumerate() {
            let mut store0 = initial_store;
            let mut store1 = initial_store;
            let mut store2 = initial_store;
            let mut store3 = initial_store;

            let v_dx = v_px + x * 16;

            for (j, &k_weight) in weights.iter().enumerate() {
                let py = bounds.start + j;
                let src_ptr = src.get_unchecked((src_stride * py + v_dx)..);

                let v_weight = _mm_set1_epi16(k_weight);

                let item_row0 = _mm_loadu_si128(src_ptr.as_ptr() as *const __m128i);
                let item_row1 = _mm_loadu_si128(src_ptr.as_ptr().add(8) as *const __m128i);

                store0 = _mm_add_epi32(
                    store0,
                    _mm_madd_epi16(_mm_unpacklo_epi16(item_row0, zeros), v_weight),
                );
                store1 = _mm_add_epi32(
                    store1,
                    _mm_madd_epi16(_mm_unpackhi_epi16(item_row0, zeros), v_weight),
                );
                store2 = _mm_add_epi32(
                    store2,
                    _mm_madd_epi16(_mm_unpacklo_epi16(item_row1, zeros), v_weight),
                );
                store3 = _mm_add_epi32(
                    store3,
                    _mm_madd_epi16(_mm_unpackhi_epi16(item_row1, zeros), v_weight),
                );
            }

            let v_st0 = _mm_srai_epi32::<PRECISION>(store0);
            let v_st1 = _mm_srai_epi32::<PRECISION>(store1);
            let v_st2 = _mm_srai_epi32::<PRECISION>(store2);
            let v_st3 = _mm_srai_epi32::<PRECISION>(store3);

            let item0 = _mm_min_epi16(_mm_packus_epi32(v_st0, v_st1), v_max_colors);
            let item1 = _mm_min_epi16(_mm_packus_epi32(v_st2, v_st3), v_max_colors);

            _mm_storeu_si128(dst.as_mut_ptr().cast(), item0);
            _mm_storeu_si128(dst.as_mut_ptr().add(8).cast(), item1);

            cx += 16;
        }

        let tail16 = dst.chunks_exact_mut(16).into_remainder();
        let iter8 = tail16.chunks_exact_mut(8);

        let v_px = cx;

        for (x, dst) in iter8.enumerate() {
            let mut store0 = initial_store;
            let mut store1 = initial_store;

            let v_dx = v_px + x * 8;

            for (j, &k_weight) in weights.iter().enumerate() {
                let py = bounds.start + j;
                let src_ptr = src.get_unchecked((src_stride * py + v_dx)..);

                let v_weight = _mm_set1_epi16(k_weight);

                let item_row = _mm_loadu_si128(src_ptr.as_ptr() as *const __m128i);

                store0 = _mm_add_epi32(
                    store0,
                    _mm_madd_epi16(_mm_unpacklo_epi16(item_row, zeros), v_weight),
                );
                store1 = _mm_add_epi32(
                    store1,
                    _mm_madd_epi16(_mm_unpackhi_epi16(item_row, zeros), v_weight),
                );
            }

            let v_st0 = _mm_srai_epi32::<PRECISION>(store0);
            let v_st1 = _mm_srai_epi32::<PRECISION>(store1);

            let item = _mm_min_epi16(_mm_packus_epi32(v_st0, v_st1), v_max_colors);
            _mm_storeu_si128(dst.as_mut_ptr().cast(), item);

            cx += 8;
        }

        let tail8 = tail16.chunks_exact_mut(8).into_remainder();
        let iter4 = tail8.chunks_exact_mut(4);

        let v_cx = cx;

        for (x, dst) in iter4.enumerate() {
            let mut store0 = initial_store;

            let v_dx = v_cx + x * 4;

            for (j, &k_weight) in weights.iter().enumerate() {
                let py = bounds.start + j;
                let src_ptr = src.get_unchecked((src_stride * py + v_dx)..);

                let v_weight = _mm_set1_epi16(k_weight);

                let item_row = _mm_loadu_si64(src_ptr.as_ptr() as *const u8);

                store0 = _mm_add_epi32(
                    store0,
                    _mm_madd_epi16(_mm_unpacklo_epi16(item_row, zeros), v_weight),
                );
            }

            let v_st = _mm_srai_epi32::<PRECISION>(store0);

            let u_store0 = _mm_min_epi16(_mm_packus_epi32(v_st, v_st), v_max_colors);
            _mm_storeu_si64(dst.as_mut_ptr() as *mut u8, u_store0);

            cx += 4;
        }

        let tail4 = tail8.chunks_exact_mut(4).into_remainder();

        let a_px = cx;

        for (x, dst) in tail4.iter_mut().enumerate() {
            let mut store0 = ROUNDING_CONST;

            let v_px = a_px + x;

            for (j, &k_weight) in weights.iter().enumerate() {
                let py = bounds.start + j;
                let offset = src_stride * py + v_px;
                let src_ptr = src.get_unchecked(offset..(offset + 1));

                store0 = store0.wrapping_add((src_ptr[0] as i32).wrapping_mul(k_weight as i32));
            }

            *dst = (store0 >> PRECISION).max(0).min(max_colors as i32) as u16;
        }
    }
}