/*
* Copyright (c) 2016 Clément Bœsch <clement stupeflix.com>
* Copyright (c) 2016 Matthieu Bouron <matthieu.bouron stupeflix.com>
*
* 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/arm/asm.S"
function ff_hscale_8_to_15_neon, export=1
push {r4-r12, lr}
vpush {q4-q7}
ldr r4, [sp, #104] @ filter
ldr r5, [sp, #108] @ filterPos
ldr r6, [sp, #112] @ filterSize
add r10, r4, r6, lsl #1 @ filter2 = filter + filterSize * 2
1: ldr r8, [r5], #4 @ filterPos[0]
ldr r9, [r5], #4 @ filterPos[1]
vmov.s32 q4, #0 @ val accumulator
vmov.s32 q5, #0 @ val accumulator
mov r7, r6 @ tmpfilterSize = filterSize
mov r0, r3 @ srcp
2: add r11, r0, r8 @ srcp + filterPos[0]
add r12, r0, r9 @ srcp + filterPos[1]
vld1.8 d0, [r11] @ srcp[filterPos[0] + {0..7}]
vld1.8 d2, [r12] @ srcp[filterPos[1] + {0..7}]
vld1.16 {q2}, [r4]! @ load 8x16-bit filter values
vld1.16 {q3}, [r10]! @ load 8x16-bit filter values
vmovl.u8 q0, d0 @ unpack src values to 16-bit
vmovl.u8 q1, d2 @ unpack src values to 16-bit
vmull.s16 q8, d0, d4 @ srcp[filterPos[0] + {0..7}] * filter[{0..7}] (part 1)
vmull.s16 q9, d1, d5 @ srcp[filterPos[0] + {0..7}] * filter[{0..7}] (part 2)
vmull.s16 q10, d2, d6 @ srcp[filterPos[1] + {0..7}] * filter[{0..7}] (part 1)
vmull.s16 q11, d3, d7 @ srcp[filterPos[1] + {0..7}] * filter[{0..7}] (part 2)
vpadd.s32 d16, d16, d17 @ horizontal pair adding of the 8x32-bit multiplied values into 4x32-bit (part 1)
vpadd.s32 d17, d18, d19 @ horizontal pair adding of the 8x32-bit multiplied values into 4x32-bit (part 2)
vpadd.s32 d20, d20, d21 @ horizontal pair adding of the 8x32-bit multiplied values into 4x32-bit (part 1)
vpadd.s32 d21, d22, d23 @ horizontal pair adding of the 8x32-bit multiplied values into 4x32-bit (part 2)
vadd.s32 q4, q8 @ update val accumulator
vadd.s32 q5, q10 @ update val accumulator
add r0, #8 @ srcp += 8
subs r7, #8 @ tmpfilterSize -= 8
bgt 2b @ loop until tmpfilterSize is consumed
mov r4, r10 @ filter = filter2
add r10, r10, r6, lsl #1 @ filter2 += filterSize * 2
vpadd.s32 d8, d8, d9 @ horizontal pair adding of the 8x32-bit sums into 4x32-bit (part 1)
vpadd.s32 d9, d10, d11 @ horizontal pair adding of the 8x32-bit sums into 4x32-bit (part 2)
vpadd.s32 d8, d8, d9 @ horizontal pair adding of the 4x32-bit sums into 2x32-bit
vqshrn.s32 d8, q4, #7 @ shift and clip the 2x16-bit final values
vst1.32 {d8[0]},[r1]! @ write destination
subs r2, #2 @ dstW -= 2
bgt 1b @ loop until end of line
vpop {q4-q7}
pop {r4-r12, lr}
mov pc, lr
endfunc