/*
* Copyright (c) 2016 Clément Bœsch <clement 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/aarch64/asm.S"
function ff_hscale_8_to_15_neon, export=1
sbfiz x7, x6, #1, #32 // filterSize*2 (*2 because int16)
1: ldr w8, [x5], #4 // filterPos[idx]
ldr w0, [x5], #4 // filterPos[idx + 1]
ldr w11, [x5], #4 // filterPos[idx + 2]
ldr w9, [x5], #4 // filterPos[idx + 3]
mov x16, x4 // filter0 = filter
add x12, x16, x7 // filter1 = filter0 + filterSize*2
add x13, x12, x7 // filter2 = filter1 + filterSize*2
add x4, x13, x7 // filter3 = filter2 + filterSize*2
movi v0.2D, #0 // val sum part 1 (for dst[0])
movi v1.2D, #0 // val sum part 2 (for dst[1])
movi v2.2D, #0 // val sum part 3 (for dst[2])
movi v3.2D, #0 // val sum part 4 (for dst[3])
add x17, x3, w8, UXTW // srcp + filterPos[0]
add x8, x3, w0, UXTW // srcp + filterPos[1]
add x0, x3, w11, UXTW // srcp + filterPos[2]
add x11, x3, w9, UXTW // srcp + filterPos[3]
mov w15, w6 // filterSize counter
2: ld1 {v4.8B}, [x17], #8 // srcp[filterPos[0] + {0..7}]
ld1 {v5.8H}, [x16], #16 // load 8x16-bit filter values, part 1
ld1 {v6.8B}, [x8], #8 // srcp[filterPos[1] + {0..7}]
ld1 {v7.8H}, [x12], #16 // load 8x16-bit at filter+filterSize
uxtl v4.8H, v4.8B // unpack part 1 to 16-bit
smlal v0.4S, v4.4H, v5.4H // v0 accumulates srcp[filterPos[0] + {0..3}] * filter[{0..3}]
smlal2 v0.4S, v4.8H, v5.8H // v0 accumulates srcp[filterPos[0] + {4..7}] * filter[{4..7}]
ld1 {v16.8B}, [x0], #8 // srcp[filterPos[2] + {0..7}]
ld1 {v17.8H}, [x13], #16 // load 8x16-bit at filter+2*filterSize
uxtl v6.8H, v6.8B // unpack part 2 to 16-bit
smlal v1.4S, v6.4H, v7.4H // v1 accumulates srcp[filterPos[1] + {0..3}] * filter[{0..3}]
uxtl v16.8H, v16.8B // unpack part 3 to 16-bit
smlal v2.4S, v16.4H, v17.4H // v2 accumulates srcp[filterPos[2] + {0..3}] * filter[{0..3}]
smlal2 v2.4S, v16.8H, v17.8H // v2 accumulates srcp[filterPos[2] + {4..7}] * filter[{4..7}]
ld1 {v18.8B}, [x11], #8 // srcp[filterPos[3] + {0..7}]
smlal2 v1.4S, v6.8H, v7.8H // v1 accumulates srcp[filterPos[1] + {4..7}] * filter[{4..7}]
ld1 {v19.8H}, [x4], #16 // load 8x16-bit at filter+3*filterSize
subs w15, w15, #8 // j -= 8: processed 8/filterSize
uxtl v18.8H, v18.8B // unpack part 4 to 16-bit
smlal v3.4S, v18.4H, v19.4H // v3 accumulates srcp[filterPos[3] + {0..3}] * filter[{0..3}]
smlal2 v3.4S, v18.8H, v19.8H // v3 accumulates srcp[filterPos[3] + {4..7}] * filter[{4..7}]
b.gt 2b // inner loop if filterSize not consumed completely
addp v0.4S, v0.4S, v0.4S // part0 horizontal pair adding
addp v1.4S, v1.4S, v1.4S // part1 horizontal pair adding
addp v2.4S, v2.4S, v2.4S // part2 horizontal pair adding
addp v3.4S, v3.4S, v3.4S // part3 horizontal pair adding
addp v0.4S, v0.4S, v0.4S // part0 horizontal pair adding
addp v1.4S, v1.4S, v1.4S // part1 horizontal pair adding
addp v2.4S, v2.4S, v2.4S // part2 horizontal pair adding
addp v3.4S, v3.4S, v3.4S // part3 horizontal pair adding
zip1 v0.4S, v0.4S, v1.4S // part01 = zip values from part0 and part1
zip1 v2.4S, v2.4S, v3.4S // part23 = zip values from part2 and part3
mov v0.d[1], v2.d[0] // part0123 = zip values from part01 and part23
subs w2, w2, #4 // dstW -= 4
sqshrn v0.4H, v0.4S, #7 // shift and clip the 2x16-bit final values
st1 {v0.4H}, [x1], #8 // write to destination part0123
b.gt 1b // loop until end of line
ret
endfunc