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/*
* Copyright (c) 2022 Jonathan Swinney <jswinney@amazon.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_pix_abs16_neon, export=1
// x0 unused
// x1 uint8_t *pix1
// x2 uint8_t *pix2
// x3 ptrdiff_t stride
// w4 int h
cmp w4, #4 // if h < 4, jump to completion section
movi v16.8h, #0 // clear result accumulator
movi v17.8h, #0 // clear result accumulator
b.lt 2f
1:
ld1 {v0.16b}, [x1], x3 // load pix1
ld1 {v4.16b}, [x2], x3 // load pix2
ld1 {v1.16b}, [x1], x3 // load pix1
ld1 {v5.16b}, [x2], x3 // load pix2
uabal v16.8h, v0.8b, v4.8b // absolute difference accumulate
uabal2 v17.8h, v0.16b, v4.16b
ld1 {v2.16b}, [x1], x3 // load pix1
ld1 {v6.16b}, [x2], x3 // load pix2
uabal v16.8h, v1.8b, v5.8b // absolute difference accumulate
uabal2 v17.8h, v1.16b, v5.16b
ld1 {v3.16b}, [x1], x3
ld1 {v7.16b}, [x2], x3
uabal v16.8h, v2.8b, v6.8b
uabal2 v17.8h, v2.16b, v6.16b
sub w4, w4, #4 // h -= 4
uabal v16.8h, v3.8b, v7.8b
uabal2 v17.8h, v3.16b, v7.16b
cmp w4, #4 // if h >= 4, loop
b.ge 1b
cbnz w4, 2f // if iterations remain, jump to completion section
add v16.8h, v16.8h, v17.8h
uaddlv s16, v16.8h // add up everything in v16 accumulator
fmov w0, s16 // copy result to general purpose register
ret
2:
ld1 {v0.16b}, [x1], x3 // load pix1
ld1 {v4.16b}, [x2], x3 // load pix2
subs w4, w4, #1 // h -= 1
uabal v16.8h, v0.8b, v4.8b // absolute difference accumulate
uabal2 v17.8h, v0.16b, v4.16b
b.ne 2b
add v16.8h, v16.8h, v17.8h
uaddlv s16, v16.8h // add up everything in v16 accumulator
fmov w0, s16 // copy result to general purpose register
ret
endfunc
function ff_pix_abs16_xy2_neon, export=1
// x0 unused
// x1 uint8_t *pix1
// x2 uint8_t *pix2
// x3 ptrdiff_t stride
// w4 int h
add x5, x2, x3 // use x5 to hold uint8_t *pix3
movi v21.8h, #0 // initialize the result register
movi v22.8h, #0 // initialize the result register
// Load initial pix2 values for either the unrolled version or completion version.
ldur q4, [x2, #1] // load pix2+1
ldr q3, [x2] // load pix2
uaddl v2.8h, v4.8b, v3.8b // pix2 + pix2+1 0..7
uaddl2 v3.8h, v4.16b, v3.16b // pix2 + pix2+1 8..15
cmp w4, #4 // if h < 4 jump to the completion version
b.lt 2f
1:
// This is an unrolled implementation. It completes 4 iterations of the C for each branch.
// In each iteration, pix2[i+1] == pix3[i]. This means we need only three loads per iteration,
// plus two at the beginning to start.
ldur q5, [x5, #1] // load pix3+1
ld1 {v4.16b}, [x5], x3 // load pix3
ld1 {v1.16b}, [x1], x3 // load pix1
ldur q7, [x5, #1] // load pix3+1
ld1 {v6.16b}, [x5], x3 // load pix3
ld1 {v16.16b}, [x1], x3 // load pix1
// These blocks compute the average: avg(pix2[n], pix2[n+1], pix3[n], pix3[n+1])
uaddl v30.8h, v4.8b, v5.8b // pix3 + pix3+1 0..7
uaddl2 v31.8h, v4.16b, v5.16b // pix3 + pix3+1 8..15
ldur q19, [x5, #1] // load pix3+1
add v23.8h, v2.8h, v30.8h // add up 0..7, using pix2 + pix2+1 values from previous iteration
add v24.8h, v3.8h, v31.8h // add up 8..15, using pix2 + pix2+1 values from previous iteration
ld1 {v18.16b}, [x5], x3 // load pix3
ld1 {v17.16b}, [x1], x3 // load pix1
rshrn v23.8b, v23.8h, #2 // shift right 2 0..7 (rounding shift right)
rshrn2 v23.16b, v24.8h, #2 // shift right 2 8..15
uaddl v2.8h, v6.8b, v7.8b // pix3 + pix3+1 0..7
uaddl2 v3.8h, v6.16b, v7.16b // pix3 + pix3+1 8..15
ldur q7, [x5, #1] // load pix3+1
add v26.8h, v30.8h, v2.8h // add up 0..7, using pix2 + pix2+1 values from pix3 above
add v27.8h, v31.8h, v3.8h // add up 8..15, using pix2 + pix2+1 values from pix3 above
uabal v21.8h, v1.8b, v23.8b // absolute difference 0..7, i=0
uabal2 v22.8h, v1.16b, v23.16b // absolute difference 8..15, i=0
ld1 {v6.16b}, [x5], x3 // load pix3
ld1 {v20.16b}, [x1], x3 // load pix1
rshrn v26.8b, v26.8h, #2 // shift right 2 0..7 (rounding shift right)
rshrn2 v26.16b, v27.8h, #2 // shift right 2 8..15
uaddl v4.8h, v18.8b, v19.8b // pix3 + pix3+1 0..7
uaddl2 v5.8h, v18.16b, v19.16b // pix3 + pix3+1 8..15
add v28.8h, v2.8h, v4.8h // add up 0..7, using pix2 + pix2+1 values from pix3 above
add v29.8h, v3.8h, v5.8h // add up 8..15, using pix2 + pix2+1 values from pix3 above
rshrn v28.8b, v28.8h, #2 // shift right 2 0..7 (rounding shift right)
rshrn2 v28.16b, v29.8h, #2 // shift right 2 8..15
uabal v21.8h, v16.8b, v26.8b // absolute difference 0..7, i=1
uabal2 v22.8h, v16.16b, v26.16b // absolute difference 8..15, i=1
uaddl v2.8h, v6.8b, v7.8b // pix3 + pix3+1 0..7
uaddl2 v3.8h, v6.16b, v7.16b // pix3 + pix3+1 8..15
add v30.8h, v4.8h, v2.8h // add up 0..7, using pix2 + pix2+1 values from pix3 above
add v31.8h, v5.8h, v3.8h // add up 8..15, using pix2 + pix2+1 values from pix3 above
rshrn v30.8b, v30.8h, #2 // shift right 2 0..7 (rounding shift right)
rshrn2 v30.16b, v31.8h, #2 // shift right 2 8..15
sub w4, w4, #4 // h -= 4
uabal v21.8h, v17.8b, v28.8b // absolute difference 0..7, i=2
uabal2 v22.8h, v17.16b, v28.16b // absolute difference 8..15, i=2
cmp w4, #4 // loop if h >= 4
uabal v21.8h, v20.8b, v30.8b // absolute difference 0..7, i=3
uabal2 v22.8h, v20.16b, v30.16b // absolute difference 8..15, i=3
b.ge 1b
cbnz w4, 2f // if iterations remain jump to completion section
add v4.8h, v21.8h, v22.8h
uaddlv s0, v4.8h // finish adding up accumulated values
fmov w0, s0 // copy result to general purpose register
ret
2:
// v2 and v3 are set either at the end of this loop or at from the unrolled version
// which branches here to complete iterations when h % 4 != 0.
ldur q5, [x5, #1] // load pix3+1
ld1 {v4.16b}, [x5], x3 // load pix3
ld1 {v1.16b}, [x1], x3 // load pix1
subs w4, w4, #1 // decrement h
uaddl v18.8h, v4.8b, v5.8b // pix3 + pix3+1 0..7
uaddl2 v19.8h, v4.16b, v5.16b // pix3 + pix3+1 8..15
add v16.8h, v2.8h, v18.8h // add up 0..7, using pix2 + pix2+1 values from previous iteration
add v17.8h, v3.8h, v19.8h // add up 8..15, using pix2 + pix2+1 values from previous iteration
// divide by 4 to compute the average of values summed above
rshrn v16.8b, v16.8h, #2 // shift right by 2 0..7 (rounding shift right)
rshrn2 v16.16b, v17.8h, #2 // shift right by 2 8..15
uabal v21.8h, v1.8b, v16.8b // absolute difference 0..7
uabal2 v22.8h, v1.16b, v16.16b // absolute difference accumulate 8..15
mov v2.16b, v18.16b // pix3 -> pix2
mov v3.16b, v19.16b // pix3+1 -> pix2+1
b.ne 2b // loop if h > 0
add v4.8h, v21.8h, v22.8h
uaddlv s0, v4.8h // finish adding up accumulated values
fmov w0, s0 // copy result to general purpose register
ret
endfunc
function ff_pix_abs16_x2_neon, export=1
// x0 unused
// x1 uint8_t *pix1
// x2 uint8_t *pix2
// x3 ptrdiff_t stride
// w4 int h
cmp w4, #4
// initialize buffers
movi v16.8h, #0
movi v17.8h, #0
add x5, x2, #1 // pix2 + 1
b.lt 2f
// make 4 iterations at once
1:
// abs(pix1[0] - avg2(pix2[0], pix2[1]))
// avg2(a,b) = (((a) + (b) + 1) >> 1)
// abs(x) = (x < 0 ? -x : x)
ld1 {v1.16b}, [x2], x3
ld1 {v2.16b}, [x5], x3
urhadd v30.16b, v1.16b, v2.16b
ld1 {v0.16b}, [x1], x3
uabal v16.8h, v0.8b, v30.8b
ld1 {v4.16b}, [x2], x3
uabal2 v17.8h, v0.16b, v30.16b
ld1 {v5.16b}, [x5], x3
urhadd v29.16b, v4.16b, v5.16b
ld1 {v3.16b}, [x1], x3
uabal v16.8h, v3.8b, v29.8b
ld1 {v7.16b}, [x2], x3
uabal2 v17.8h, v3.16b, v29.16b
ld1 {v22.16b}, [x5], x3
urhadd v28.16b, v7.16b, v22.16b
ld1 {v6.16b}, [x1], x3
uabal v16.8h, v6.8b, v28.8b
ld1 {v24.16b}, [x2], x3
sub w4, w4, #4
uabal2 v17.8h, v6.16b, v28.16b
ld1 {v25.16b}, [x5], x3
urhadd v27.16b, v24.16b, v25.16b
ld1 {v23.16b}, [x1], x3
cmp w4, #4
uabal v16.8h, v23.8b, v27.8b
uabal2 v17.8h, v23.16b, v27.16b
b.ge 1b
cbz w4, 3f
// iterate by one
2:
ld1 {v1.16b}, [x2], x3
ld1 {v2.16b}, [x5], x3
subs w4, w4, #1
urhadd v29.16b, v1.16b, v2.16b
ld1 {v0.16b}, [x1], x3
uabal v16.8h, v0.8b, v29.8b
uabal2 v17.8h, v0.16b, v29.16b
b.ne 2b
3:
add v16.8h, v16.8h, v17.8h
uaddlv s16, v16.8h
fmov w0, s16
ret
endfunc
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