/* -*-arm64-*- * vim: syntax=arm64asm * * AArch64 NEON optimised SAO functions for HEVC decoding * * Copyright (c) 2020 Josh Dekker * * 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] // sao_offset_val[k+1] subs w8, w8, #1 add w10, w8, w5 // k + sao_left_class and w10, w10, #0x1F strh w9, [sp, x10, lsl #1] bne 0b add w6, w6, #7 bic w6, w6, #7 ld1 {v16.16b-v19.16b}, [sp], #64 sub x2, x2, x6 sub x3, x3, x6 movi v20.8h, #1 1: mov w8, w6 // beginning of line 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 ld1 {v2.8b}, [x1], #8 // dst[x] = av_clip_pixel(src[x] + offset_table[src[x] >> shift]); uxtl v0.8h, v2.8b // load src[x] ushr v2.8h, v0.8h, #3 // >> BIT_DEPTH - 3 shl v1.8h, v2.8h, #1 // low (x2, accessing short) add v3.8h, v1.8h, v20.8h // +1 access upper short sli v1.8h, v3.8h, #8 // shift insert index to upper byte tbx v2.16b, {v16.16b-v19.16b}, v1.16b // table add v1.8h, v0.8h, v2.8h // src[x] + table sqxtun v4.8b, v1.8h // clip + narrow st1 {v4.8b}, [x0], #8 // store subs w8, w8, #8 // done 8 pixels bne 2b subs w7, w7, #1 // finished line, prep. new add x0, x0, x2 // dst += stride_dst add x1, x1, x3 // src += stride_src bne 1b ret endfunc // ASSUMES STRIDE_SRC = 192 .Lsao_edge_pos: .word 1 // horizontal .word 192 // vertical .word 192 + 1 // 45 degree .word 192 - 1 // 135 degree // ff_hevc_sao_edge_filter_16x16_8_neon(char *dst, char *src, ptrdiff stride_dst, // int16 *sao_offset_val, int eo, int width, int height) function ff_hevc_sao_edge_filter_16x16_8_neon, export=1 adr x7, .Lsao_edge_pos ld1 {v3.8h}, [x3] // load sao_offset_val add w5, w5, #0xF bic w5, w5, #0xF ldr w4, [x7, w4, uxtw #2] // stride_src mov v3.h[7], v3.h[0] // reorder to [1,2,0,3,4] mov v3.h[0], v3.h[1] mov v3.h[1], v3.h[2] mov v3.h[2], v3.h[7] // split 16bit values into two tables uzp2 v1.16b, v3.16b, v3.16b // sao_offset_val -> upper uzp1 v0.16b, v3.16b, v3.16b // sao_offset_val -> lower movi v2.16b, #2 mov x15, #192 // strides between end of line and next src/dst sub x15, x15, x5 // stride_src - width sub x16, x2, x5 // stride_dst - width mov x11, x1 // copy base src 1: // new line mov x14, x5 // copy width sub x12, x11, x4 // src_a (prev) = src - sao_edge_pos add x13, x11, x4 // src_b (next) = src + sao_edge_pos 2: // process 16 bytes ld1 {v3.16b}, [x11], #16 // load src ld1 {v4.16b}, [x12], #16 // load src_a (prev) ld1 {v5.16b}, [x13], #16 // load src_b (next) cmhi v16.16b, v4.16b, v3.16b // (prev > cur) cmhi v17.16b, v3.16b, v4.16b // (cur > prev) cmhi v18.16b, v5.16b, v3.16b // (next > cur) cmhi v19.16b, v3.16b, v5.16b // (cur > next) sub v20.16b, v16.16b, v17.16b // diff0 = CMP(cur, prev) = (cur > prev) - (cur < prev) sub v21.16b, v18.16b, v19.16b // diff1 = CMP(cur, next) = (cur > next) - (cur < next) add v20.16b, v20.16b, v21.16b // diff = diff0 + diff1 add v20.16b, v20.16b, v2.16b // offset_val = diff + 2 tbl v16.16b, {v0.16b}, v20.16b tbl v17.16b, {v1.16b}, v20.16b uxtl v20.8h, v3.8b // src[0:7] uxtl2 v21.8h, v3.16b // src[7:15] zip1 v18.16b, v16.16b, v17.16b // sao_offset_val lower -> zip2 v19.16b, v16.16b, v17.16b // sao_offset_val upper -> sqadd v20.8h, v18.8h, v20.8h // + sao_offset_val sqadd v21.8h, v19.8h, v21.8h sqxtun v3.8b, v20.8h sqxtun2 v3.16b, v21.8h st1 {v3.16b}, [x0], #16 subs x14, x14, #16 // filtered 16 bytes b.ne 2b // do we have width to filter? // no width to filter, setup next line add x11, x11, x15 // stride src to next line add x0, x0, x16 // stride dst to next line subs w6, w6, #1 // filtered line b.ne 1b // do we have lines to process? // no lines to filter ret endfunc