| /* -*-arm64-*- |
| * vim: syntax=arm64asm |
| * |
| * AArch64 NEON optimised SAO functions for HEVC decoding |
| * |
| * Copyright (c) 2020 Josh Dekker <josh@itanimul.li> |
| * |
| * This file is part of FFmpeg. |
| * |
| * FFmpeg is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2.1 of the License, or (at your option) any later version. |
| * |
| * FFmpeg is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with FFmpeg; if not, write to the Free Software |
| * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| */ |
| |
| #include "libavutil/aarch64/asm.S" |
| |
| // void sao_band_filter(uint8_t *_dst, uint8_t *_src, |
| // ptrdiff_t stride_dst, ptrdiff_t stride_src, |
| // int16_t *sao_offset_val, int sao_left_class, |
| // int width, int height) |
| function ff_hevc_sao_band_filter_8x8_8_neon, export=1 |
| sub sp, sp, #64 |
| stp xzr, xzr, [sp] |
| stp xzr, xzr, [sp, #16] |
| stp xzr, xzr, [sp, #32] |
| stp xzr, xzr, [sp, #48] |
| mov w8, #4 |
| 0: |
| ldrsh x9, [x4, x8, lsl #1] // x9 = sao_offset_val[k+1] |
| subs w8, w8, #1 |
| add w10, w8, w5 // x10 = k + sao_left_class |
| and w10, w10, #0x1F |
| strh w9, [sp, x10, lsl #1] |
| bne 0b |
| ld1 {v16.16b-v19.16b}, [sp], #64 |
| movi v20.8h, #1 |
| 1: // beginning of line |
| mov w8, w6 |
| 2: |
| // Simple layout for accessing 16bit values |
| // with 8bit LUT. |
| // |
| // 00 01 02 03 04 05 06 07 |
| // +-----------------------------------> |
| // |xDE#xAD|xCA#xFE|xBE#xEF|xFE#xED|.... |
| // +-----------------------------------> |
| // i-0 i-1 i-2 i-3 |
| // dst[x] = av_clip_pixel(src[x] + offset_table[src[x] >> shift]); |
| ld1 {v2.8b}, [x1] |
| // load src[x] |
| uxtl v0.8h, v2.8b |
| // >> shift |
| ushr v2.8h, v0.8h, #3 // BIT_DEPTH - 3 |
| // x2 (access lower short) |
| shl v1.8h, v2.8h, #1 // low (x2, accessing short) |
| // +1 access upper short |
| add v3.8h, v1.8h, v20.8h |
| // shift insert index to upper byte |
| sli v1.8h, v3.8h, #8 |
| // table |
| tbx v2.16b, {v16.16b-v19.16b}, v1.16b |
| // src[x] + table |
| add v1.8h, v0.8h, v2.8h |
| // clip + narrow |
| sqxtun v4.8b, v1.8h |
| // store |
| st1 {v4.8b}, [x0] |
| // done 8 pixels |
| subs w8, w8, #8 |
| bne 2b |
| // finished line |
| subs w7, w7, #1 |
| add x0, x0, x2 // dst += stride_dst |
| add x1, x1, x3 // src += stride_src |
| bne 1b |
| ret |
| endfunc |
