shithub: dav1d

ref: a0678eac0ee1a67ff871247b551e42fa448591b7
dir: /src/arm/32/cdef.S/

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/*
 * Copyright © 2018, VideoLAN and dav1d authors
 * Copyright © 2019, Martin Storsjo
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "src/arm/asm.S"
#include "util.S"

// n1 = s0/d0
// w1 = d0/q0
// n2 = s4/d2
// w2 = d2/q1
.macro pad_top_bottom s1, s2, w, stride, n1, w1, n2, w2, align, ret
        tst             r6,  #1 // CDEF_HAVE_LEFT
        beq             2f
        // CDEF_HAVE_LEFT
        tst             r6,  #2 // CDEF_HAVE_RIGHT
        beq             1f
        // CDEF_HAVE_LEFT+CDEF_HAVE_RIGHT
        ldrh            r12, [\s1, #-2]
        vldr            \n1, [\s1]
        vdup.16         d4,  r12
        ldrh            r12, [\s1, #\w]
        vmov.16         d4[1], r12
        ldrh            r12, [\s2, #-2]
        vldr            \n2, [\s2]
        vmov.16         d4[2], r12
        ldrh            r12, [\s2, #\w]
        vmovl.u8        q0,  d0
        vmov.16         d4[3], r12
        vmovl.u8        q1,  d2
        vmovl.u8        q2,  d4
        vstr            s8,  [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s9,  [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        vstr            s10, [r0, #-4]
        vst1.16         {\w2}, [r0, :\align]
        vstr            s11, [r0, #2*\w]
.if \ret
        pop             {r4-r7,pc}
.else
        add             r0,  r0,  #2*\stride
        b               3f
.endif

1:
        // CDEF_HAVE_LEFT+!CDEF_HAVE_RIGHT
        ldrh            r12, [\s1, #-2]
        vldr            \n1, [\s1]
        vdup.16         d4,  r12
        ldrh            r12, [\s2, #-2]
        vldr            \n2, [\s2]
        vmovl.u8        q0,  d0
        vmov.16         d4[1], r12
        vmovl.u8        q1,  d2
        vmovl.u8        q2,  d4
        vstr            s8,  [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s12, [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        vstr            s9,  [r0, #-4]
        vst1.16         {\w2}, [r0, :\align]
        vstr            s12, [r0, #2*\w]
.if \ret
        pop             {r4-r7,pc}
.else
        add             r0,  r0,  #2*\stride
        b               3f
.endif

2:
        // !CDEF_HAVE_LEFT
        tst             r6,  #2 // CDEF_HAVE_RIGHT
        beq             1f
        // !CDEF_HAVE_LEFT+CDEF_HAVE_RIGHT
        vldr            \n1, [\s1]
        ldrh            r12, [\s1, #\w]
        vldr            \n2, [\s2]
        vdup.16         d4,  r12
        ldrh            r12, [\s2, #\w]
        vmovl.u8        q0,  d0
        vmov.16         d4[1], r12
        vmovl.u8        q1,  d2
        vmovl.u8        q2,  d4
        vstr            s12, [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s8,  [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        vstr            s12, [r0, #-4]
        vst1.16         {\w2}, [r0, :\align]
        vstr            s9,  [r0, #2*\w]
.if \ret
        pop             {r4-r7,pc}
.else
        add             r0,  r0,  #2*\stride
        b               3f
.endif

1:
        // !CDEF_HAVE_LEFT+!CDEF_HAVE_RIGHT
        vldr            \n1, [\s1]
        vldr            \n2, [\s2]
        vmovl.u8        q0,  d0
        vmovl.u8        q1,  d2
        vstr            s12, [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s12, [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        vstr            s12, [r0, #-4]
        vst1.16         {\w2}, [r0, :\align]
        vstr            s12, [r0, #2*\w]
.if \ret
        pop             {r4-r7,pc}
.else
        add             r0,  r0,  #2*\stride
.endif
3:
.endm

.macro load_n_incr dst, src, incr, w
.if \w == 4
        vld1.32         {\dst\()[0]}, [\src, :32], \incr
.else
        vld1.8          {\dst\()},    [\src, :64], \incr
.endif
.endm

// void dav1d_cdef_paddingX_8bpc_neon(uint16_t *tmp, const pixel *src,
//                                    ptrdiff_t src_stride, const pixel (*left)[2],
//                                    const pixel *const top, int h,
//                                    enum CdefEdgeFlags edges);

// n1 = s0/d0
// w1 = d0/q0
// n2 = s4/d2
// w2 = d2/q1
.macro padding_func w, stride, n1, w1, n2, w2, align
function cdef_padding\w\()_8bpc_neon, export=1
        push            {r4-r7,lr}
        ldrd            r4,  r5,  [sp, #20]
        ldr             r6,  [sp, #28]
        cmp             r6,  #0xf // fully edged
        beq             cdef_padding\w\()_edged_8bpc_neon
        vmov.i16        q3,  #0x8000
        tst             r6,  #4 // CDEF_HAVE_TOP
        bne             1f
        // !CDEF_HAVE_TOP
        sub             r12, r0,  #2*(2*\stride+2)
        vmov.i16        q2,  #0x8000
        vst1.16         {q2,q3}, [r12]!
.if \w == 8
        vst1.16         {q2,q3}, [r12]!
.endif
        b               3f
1:
        // CDEF_HAVE_TOP
        add             r7,  r4,  r2
        sub             r0,  r0,  #2*(2*\stride)
        pad_top_bottom  r4,  r7,  \w, \stride, \n1, \w1, \n2, \w2, \align, 0

        // Middle section
3:
        tst             r6,  #1 // CDEF_HAVE_LEFT
        beq             2f
        // CDEF_HAVE_LEFT
        tst             r6,  #2 // CDEF_HAVE_RIGHT
        beq             1f
        // CDEF_HAVE_LEFT+CDEF_HAVE_RIGHT
0:
        ldrh            r12, [r3], #2
        vldr            \n1, [r1]
        vdup.16         d2,  r12
        ldrh            r12, [r1, #\w]
        add             r1,  r1,  r2
        subs            r5,  r5,  #1
        vmov.16         d2[1], r12
        vmovl.u8        q0,  d0
        vmovl.u8        q1,  d2
        vstr            s4,  [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s5,  [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        bgt             0b
        b               3f
1:
        // CDEF_HAVE_LEFT+!CDEF_HAVE_RIGHT
        ldrh            r12, [r3], #2
        load_n_incr     d0,  r1,  r2,  \w
        vdup.16         d2,  r12
        subs            r5,  r5,  #1
        vmovl.u8        q0,  d0
        vmovl.u8        q1,  d2
        vstr            s4,  [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s12, [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        bgt             1b
        b               3f
2:
        tst             r6,  #2 // CDEF_HAVE_RIGHT
        beq             1f
        // !CDEF_HAVE_LEFT+CDEF_HAVE_RIGHT
0:
        ldrh            r12, [r1, #\w]
        load_n_incr     d0,  r1,  r2,  \w
        vdup.16         d2,  r12
        subs            r5,  r5,  #1
        vmovl.u8        q0,  d0
        vmovl.u8        q1,  d2
        vstr            s12, [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s4,  [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        bgt             0b
        b               3f
1:
        // !CDEF_HAVE_LEFT+!CDEF_HAVE_RIGHT
        load_n_incr     d0,  r1,  r2,  \w
        subs            r5,  r5,  #1
        vmovl.u8        q0,  d0
        vstr            s12, [r0, #-4]
        vst1.16         {\w1}, [r0, :\align]
        vstr            s12, [r0, #2*\w]
        add             r0,  r0,  #2*\stride
        bgt             1b

3:
        tst             r6,  #8 // CDEF_HAVE_BOTTOM
        bne             1f
        // !CDEF_HAVE_BOTTOM
        sub             r12, r0,  #4
        vmov.i16        q2,  #0x8000
        vst1.16         {q2,q3}, [r12]!
.if \w == 8
        vst1.16         {q2,q3}, [r12]!
.endif
        pop             {r4-r7,pc}
1:
        // CDEF_HAVE_BOTTOM
        add             r7,  r1,  r2
        pad_top_bottom  r1,  r7,  \w, \stride, \n1, \w1, \n2, \w2, \align, 1
endfunc
.endm

padding_func 8, 16, d0, q0, d2, q1, 128
padding_func 4, 8,  s0, d0, s4, d2, 64

// void cdef_paddingX_edged_8bpc_neon(uint16_t *tmp, const pixel *src,
//                                    ptrdiff_t src_stride, const pixel (*left)[2],
//                                    const pixel *const top, int h,
//                                    enum CdefEdgeFlags edges);

.macro padding_func_edged w, stride, reg, align
function cdef_padding\w\()_edged_8bpc_neon
        sub             r0,  r0,  #(2*\stride)

        ldrh            r12, [r4, #-2]
        vldr            \reg, [r4]
        add             r7,  r4,  r2
        strh            r12, [r0, #-2]
        ldrh            r12, [r4, #\w]
        vstr            \reg, [r0]
        strh            r12, [r0, #\w]

        ldrh            r12, [r7, #-2]
        vldr            \reg, [r7]
        strh            r12, [r0, #\stride-2]
        ldrh            r12, [r7, #\w]
        vstr            \reg, [r0, #\stride]
        strh            r12, [r0, #\stride+\w]
        add             r0,  r0,  #2*\stride

0:
        ldrh            r12, [r3], #2
        vldr            \reg, [r1]
        str             r12, [r0, #-2]
        ldrh            r12, [r1, #\w]
        add             r1,  r1,  r2
        subs            r5,  r5,  #1
        vstr            \reg, [r0]
        str             r12, [r0, #\w]
        add             r0,  r0,  #\stride
        bgt             0b

        ldrh            r12, [r1, #-2]
        vldr            \reg, [r1]
        add             r7,  r1,  r2
        strh            r12, [r0, #-2]
        ldrh            r12, [r1, #\w]
        vstr            \reg, [r0]
        strh            r12, [r0, #\w]

        ldrh            r12, [r7, #-2]
        vldr            \reg, [r7]
        strh            r12, [r0, #\stride-2]
        ldrh            r12, [r7, #\w]
        vstr            \reg, [r0, #\stride]
        strh            r12, [r0, #\stride+\w]

        pop             {r4-r7,pc}
endfunc
.endm

padding_func_edged 8, 16, d0, 64
padding_func_edged 4, 8,  s0, 32

.macro dir_table w, stride
const directions\w
        .byte           -1 * \stride + 1, -2 * \stride + 2
        .byte            0 * \stride + 1, -1 * \stride + 2
        .byte            0 * \stride + 1,  0 * \stride + 2
        .byte            0 * \stride + 1,  1 * \stride + 2
        .byte            1 * \stride + 1,  2 * \stride + 2
        .byte            1 * \stride + 0,  2 * \stride + 1
        .byte            1 * \stride + 0,  2 * \stride + 0
        .byte            1 * \stride + 0,  2 * \stride - 1
// Repeated, to avoid & 7
        .byte           -1 * \stride + 1, -2 * \stride + 2
        .byte            0 * \stride + 1, -1 * \stride + 2
        .byte            0 * \stride + 1,  0 * \stride + 2
        .byte            0 * \stride + 1,  1 * \stride + 2
        .byte            1 * \stride + 1,  2 * \stride + 2
        .byte            1 * \stride + 0,  2 * \stride + 1
endconst
.endm

dir_table 8, 16
dir_table 4, 8

const pri_taps
        .byte           4, 2, 3, 3
endconst

.macro load_px d11, d12, d21, d22, w
.if \w == 8
        add             r6,  r2,  r9, lsl #1 // x + off
        sub             r9,  r2,  r9, lsl #1 // x - off
        vld1.16         {\d11,\d12}, [r6]    // p0
        vld1.16         {\d21,\d22}, [r9]    // p1
.else
        add             r6,  r2,  r9, lsl #1 // x + off
        sub             r9,  r2,  r9, lsl #1 // x - off
        vld1.16         {\d11}, [r6]         // p0
        add             r6,  r6,  #2*8       // += stride
        vld1.16         {\d21}, [r9]         // p1
        add             r9,  r9,  #2*8       // += stride
        vld1.16         {\d12}, [r6]         // p0
        vld1.16         {\d22}, [r9]         // p1
.endif
.endm
.macro handle_pixel s1, s2, thresh_vec, shift, tap, min
.if \min
        vmin.u16        q2,  q2,  \s1
        vmax.s16        q3,  q3,  \s1
        vmin.u16        q2,  q2,  \s2
        vmax.s16        q3,  q3,  \s2
.endif
        vabd.u16        q8,  q0,  \s1        // abs(diff)
        vabd.u16        q11, q0,  \s2        // abs(diff)
        vshl.u16        q9,  q8,  \shift     // abs(diff) >> shift
        vshl.u16        q12, q11, \shift     // abs(diff) >> shift
        vqsub.u16       q9,  \thresh_vec, q9 // clip = imax(0, threshold - (abs(diff) >> shift))
        vqsub.u16       q12, \thresh_vec, q12// clip = imax(0, threshold - (abs(diff) >> shift))
        vsub.i16        q10, \s1, q0         // diff = p0 - px
        vsub.i16        q13, \s2, q0         // diff = p1 - px
        vneg.s16        q8,  q9              // -clip
        vneg.s16        q11, q12             // -clip
        vmin.s16        q10, q10, q9         // imin(diff, clip)
        vmin.s16        q13, q13, q12        // imin(diff, clip)
        vdup.16         q9,  \tap            // taps[k]
        vmax.s16        q10, q10, q8         // constrain() = imax(imin(diff, clip), -clip)
        vmax.s16        q13, q13, q11        // constrain() = imax(imin(diff, clip), -clip)
        vmla.i16        q1,  q10, q9         // sum += taps[k] * constrain()
        vmla.i16        q1,  q13, q9         // sum += taps[k] * constrain()
.endm

// void dav1d_cdef_filterX_8bpc_neon(pixel *dst, ptrdiff_t dst_stride,
//                                   const uint16_t *tmp, int pri_strength,
//                                   int sec_strength, int dir, int damping,
//                                   int h, size_t edges);
.macro filter_func w, pri, sec, min, suffix
function cdef_filter\w\suffix\()_neon
        cmp             r8,  #0xf
        beq             cdef_filter\w\suffix\()_edged_neon
.if \pri
        movrel_local    r8,  pri_taps
        and             r9,  r3,  #1
        add             r8,  r8,  r9, lsl #1
.endif
        movrel_local    r9,  directions\w
        add             r5,  r9,  r5, lsl #1
        vmov.u16        d17, #15
        vdup.16         d16, r6              // damping

.if \pri
        vdup.16         q5,  r3              // threshold
.endif
.if \sec
        vdup.16         q7,  r4              // threshold
.endif
        vmov.16         d8[0], r3
        vmov.16         d8[1], r4
        vclz.i16        d8,  d8              // clz(threshold)
        vsub.i16        d8,  d17, d8         // ulog2(threshold)
        vqsub.u16       d8,  d16, d8         // shift = imax(0, damping - ulog2(threshold))
        vneg.s16        d8,  d8              // -shift
.if \sec
        vdup.16         q6,  d8[1]
.endif
.if \pri
        vdup.16         q4,  d8[0]
.endif

1:
.if \w == 8
        vld1.16         {q0},  [r2, :128]    // px
.else
        add             r12, r2,  #2*8
        vld1.16         {d0},  [r2,  :64]    // px
        vld1.16         {d1},  [r12, :64]    // px
.endif

        vmov.u16        q1,  #0              // sum
.if \min
        vmov.u16        q2,  q0              // min
        vmov.u16        q3,  q0              // max
.endif

        // Instead of loading sec_taps 2, 1 from memory, just set it
        // to 2 initially and decrease for the second round.
        // This is also used as loop counter.
        mov             lr,  #2              // sec_taps[0]

2:
.if \pri
        ldrsb           r9,  [r5]            // off1

        load_px         d28, d29, d30, d31, \w
.endif

.if \sec
        add             r5,  r5,  #4         // +2*2
        ldrsb           r9,  [r5]            // off2
.endif

.if \pri
        ldrb            r12, [r8]            // *pri_taps

        handle_pixel    q14, q15, q5,  q4,  r12, \min
.endif

.if \sec
        load_px         d28, d29, d30, d31, \w

        add             r5,  r5,  #8         // +2*4
        ldrsb           r9,  [r5]            // off3

        handle_pixel    q14, q15, q7,  q6,  lr, \min

        load_px         d28, d29, d30, d31, \w

        handle_pixel    q14, q15, q7,  q6,  lr, \min

        sub             r5,  r5,  #11        // r5 -= 2*(2+4); r5 += 1;
.else
        add             r5,  r5,  #1         // r5 += 1
.endif
        subs            lr,  lr,  #1         // sec_tap-- (value)
.if \pri
        add             r8,  r8,  #1         // pri_taps++ (pointer)
.endif
        bne             2b

        vshr.s16        q14, q1,  #15        // -(sum < 0)
        vadd.i16        q1,  q1,  q14        // sum - (sum < 0)
        vrshr.s16       q1,  q1,  #4         // (8 + sum - (sum < 0)) >> 4
        vadd.i16        q0,  q0,  q1         // px + (8 + sum ...) >> 4
.if \min
        vmin.s16        q0,  q0,  q3
        vmax.s16        q0,  q0,  q2         // iclip(px + .., min, max)
.endif
        vmovn.u16       d0,  q0
.if \w == 8
        add             r2,  r2,  #2*16      // tmp += tmp_stride
        subs            r7,  r7,  #1         // h--
        vst1.8          {d0}, [r0, :64], r1
.else
        vst1.32         {d0[0]}, [r0, :32], r1
        add             r2,  r2,  #2*16      // tmp += 2*tmp_stride
        subs            r7,  r7,  #2         // h -= 2
        vst1.32         {d0[1]}, [r0, :32], r1
.endif

        // Reset pri_taps and directions back to the original point
        sub             r5,  r5,  #2
.if \pri
        sub             r8,  r8,  #2
.endif

        bgt             1b
        vpop            {q4-q7}
        pop             {r4-r9,pc}
endfunc
.endm

.macro filter w
filter_func \w, pri=1, sec=0, min=0, suffix=_pri
filter_func \w, pri=0, sec=1, min=0, suffix=_sec
filter_func \w, pri=1, sec=1, min=1, suffix=_pri_sec

function cdef_filter\w\()_8bpc_neon, export=1
        push            {r4-r9,lr}
        vpush           {q4-q7}
        ldrd            r4,  r5,  [sp, #92]
        ldrd            r6,  r7,  [sp, #100]
        ldr             r8,  [sp, #108]
        cmp             r3,  #0 // pri_strength
        bne             1f
        b               cdef_filter\w\()_sec_neon // only sec
1:
        cmp             r4,  #0 // sec_strength
        bne             1f
        b               cdef_filter\w\()_pri_neon // only pri
1:
        b               cdef_filter\w\()_pri_sec_neon // both pri and sec
endfunc
.endm

filter 8
filter 4

.macro load_px_8 d11, d12, d21, d22, w
.if \w == 8
        add             r6,  r2,  r9         // x + off
        sub             r9,  r2,  r9         // x - off
        vld1.8          {\d11}, [r6]         // p0
        add             r6,  r6,  #16        // += stride
        vld1.8          {\d21}, [r9]         // p1
        add             r9,  r9,  #16        // += stride
        vld1.8          {\d12}, [r6]         // p0
        vld1.8          {\d22}, [r9]         // p1
.else
        add             r6,  r2,  r9         // x + off
        sub             r9,  r2,  r9         // x - off
        vld1.32         {\d11[0]}, [r6]      // p0
        add             r6,  r6,  #8         // += stride
        vld1.32         {\d21[0]}, [r9]      // p1
        add             r9,  r9,  #8         // += stride
        vld1.32         {\d11[1]}, [r6]      // p0
        add             r6,  r6,  #8         // += stride
        vld1.32         {\d21[1]}, [r9]      // p1
        add             r9,  r9,  #8         // += stride
        vld1.32         {\d12[0]}, [r6]      // p0
        add             r6,  r6,  #8         // += stride
        vld1.32         {\d22[0]}, [r9]      // p1
        add             r9,  r9,  #8         // += stride
        vld1.32         {\d12[1]}, [r6]      // p0
        vld1.32         {\d22[1]}, [r9]      // p1
.endif
.endm
.macro handle_pixel_8 s1, s2, thresh_vec, shift, tap, min
.if \min
        vmin.u8         q3,  q3,  \s1
        vmax.u8         q4,  q4,  \s1
        vmin.u8         q3,  q3,  \s2
        vmax.u8         q4,  q4,  \s2
.endif
        vabd.u8         q8,  q0,  \s1        // abs(diff)
        vabd.u8         q11, q0,  \s2        // abs(diff)
        vshl.u8         q9,  q8,  \shift     // abs(diff) >> shift
        vshl.u8         q12, q11, \shift     // abs(diff) >> shift
        vqsub.u8        q9,  \thresh_vec, q9 // clip = imax(0, threshold - (abs(diff) >> shift))
        vqsub.u8        q12, \thresh_vec, q12// clip = imax(0, threshold - (abs(diff) >> shift))
        vcgt.u8         q10, q0,  \s1        // px > p0
        vcgt.u8         q13, q0,  \s2        // px > p1
        vmin.u8         q9,  q9,  q8         // imin(abs(diff), clip)
        vmin.u8         q12, q12, q11        // imin(abs(diff), clip)
        vneg.s8         q8,  q9              // -imin()
        vneg.s8         q11, q12             // -imin()
        vbsl            q10, q8,  q9         // constrain() = imax(imin(diff, clip), -clip)
        vdup.8          d18, \tap            // taps[k]
        vbsl            q13, q11, q12        // constrain() = imax(imin(diff, clip), -clip)
        vmlal.s8        q1,  d20, d18        // sum += taps[k] * constrain()
        vmlal.s8        q1,  d26, d18        // sum += taps[k] * constrain()
        vmlal.s8        q2,  d21, d18        // sum += taps[k] * constrain()
        vmlal.s8        q2,  d27, d18        // sum += taps[k] * constrain()
.endm

// void cdef_filterX_edged_neon(pixel *dst, ptrdiff_t dst_stride,
//                              const uint16_t *tmp, int pri_strength,
//                              int sec_strength, int dir, int damping,
//                              int h, size_t edges);
.macro filter_func_8 w, pri, sec, min, suffix
function cdef_filter\w\suffix\()_edged_neon
.if \pri
        movrel_local    r8,  pri_taps
        and             r9,  r3,  #1
        add             r8,  r8,  r9, lsl #1
.endif
        movrel_local    r9,  directions\w
        add             r5,  r9,  r5, lsl #1
        vmov.u8         d17, #7
        vdup.8          d16, r6              // damping

        vmov.8          d8[0], r3
        vmov.8          d8[1], r4
        vclz.i8         d8,  d8              // clz(threshold)
        vsub.i8         d8,  d17, d8         // ulog2(threshold)
        vqsub.u8        d8,  d16, d8         // shift = imax(0, damping - ulog2(threshold))
        vneg.s8         d8,  d8              // -shift
.if \sec
        vdup.8          q6,  d8[1]
.endif
.if \pri
        vdup.8          q5,  d8[0]
.endif

1:
.if \w == 8
        add             r12, r2,  #16
        vld1.8          {d0},  [r2,  :64]    // px
        vld1.8          {d1},  [r12, :64]    // px
.else
        add             r12, r2,  #8
        vld1.32         {d0[0]},  [r2,  :32] // px
        add             r9,  r2,  #2*8
        vld1.32         {d0[1]},  [r12, :32] // px
        add             r12, r12, #2*8
        vld1.32         {d1[0]},  [r9,  :32] // px
        vld1.32         {d1[1]},  [r12, :32] // px
.endif

        vmov.u8         q1,  #0              // sum
        vmov.u8         q2,  #0              // sum
.if \min
        vmov.u16        q3,  q0              // min
        vmov.u16        q4,  q0              // max
.endif

        // Instead of loading sec_taps 2, 1 from memory, just set it
        // to 2 initially and decrease for the second round.
        // This is also used as loop counter.
        mov             lr,  #2              // sec_taps[0]

2:
.if \pri
        ldrsb           r9,  [r5]            // off1

        load_px_8       d28, d29, d30, d31, \w
.endif

.if \sec
        add             r5,  r5,  #4         // +2*2
        ldrsb           r9,  [r5]            // off2
.endif

.if \pri
        ldrb            r12, [r8]            // *pri_taps
        vdup.8          q7,  r3              // threshold

        handle_pixel_8  q14, q15, q7,  q5,  r12, \min
.endif

.if \sec
        load_px_8       d28, d29, d30, d31, \w

        add             r5,  r5,  #8         // +2*4
        ldrsb           r9,  [r5]            // off3

        vdup.8          q7,  r4              // threshold

        handle_pixel_8  q14, q15, q7,  q6,  lr, \min

        load_px_8       d28, d29, d30, d31, \w

        handle_pixel_8  q14, q15, q7,  q6,  lr, \min

        sub             r5,  r5,  #11        // r5 -= 2*(2+4); r5 += 1;
.else
        add             r5,  r5,  #1         // r5 += 1
.endif
        subs            lr,  lr,  #1         // sec_tap-- (value)
.if \pri
        add             r8,  r8,  #1         // pri_taps++ (pointer)
.endif
        bne             2b

        vshr.s16        q14, q1,  #15        // -(sum < 0)
        vshr.s16        q15, q2,  #15        // -(sum < 0)
        vadd.i16        q1,  q1,  q14        // sum - (sum < 0)
        vadd.i16        q2,  q2,  q15        // sum - (sum < 0)
        vrshr.s16       q1,  q1,  #4         // (8 + sum - (sum < 0)) >> 4
        vrshr.s16       q2,  q2,  #4         // (8 + sum - (sum < 0)) >> 4
        vaddw.u8        q1,  q1,  d0         // px + (8 + sum ...) >> 4
        vaddw.u8        q2,  q2,  d1         // px + (8 + sum ...) >> 4
        vqmovun.s16     d0,  q1
        vqmovun.s16     d1,  q2
.if \min
        vmin.u8         q0,  q0,  q4
        vmax.u8         q0,  q0,  q3         // iclip(px + .., min, max)
.endif
.if \w == 8
        vst1.8          {d0}, [r0, :64], r1
        add             r2,  r2,  #2*16      // tmp += 2*tmp_stride
        subs            r7,  r7,  #2         // h -= 2
        vst1.8          {d1}, [r0, :64], r1
.else
        vst1.32         {d0[0]}, [r0, :32], r1
        add             r2,  r2,  #4*8       // tmp += 4*tmp_stride
        vst1.32         {d0[1]}, [r0, :32], r1
        subs            r7,  r7,  #4         // h -= 4
        vst1.32         {d1[0]}, [r0, :32], r1
        vst1.32         {d1[1]}, [r0, :32], r1
.endif

        // Reset pri_taps and directions back to the original point
        sub             r5,  r5,  #2
.if \pri
        sub             r8,  r8,  #2
.endif

        bgt             1b
        vpop            {q4-q7}
        pop             {r4-r9,pc}
endfunc
.endm

.macro filter_8 w
filter_func_8 \w, pri=1, sec=0, min=0, suffix=_pri
filter_func_8 \w, pri=0, sec=1, min=0, suffix=_sec
filter_func_8 \w, pri=1, sec=1, min=1, suffix=_pri_sec
.endm

filter_8 8
filter_8 4

const div_table, align=4
        .short         840, 420, 280, 210, 168, 140, 120, 105
endconst

const alt_fact, align=4
        .short         420, 210, 140, 105, 105, 105, 105, 105, 140, 210, 420, 0
endconst

// int dav1d_cdef_find_dir_8bpc_neon(const pixel *img, const ptrdiff_t stride,
//                                   unsigned *const var)
function cdef_find_dir_8bpc_neon, export=1
        push            {lr}
        vpush           {q4-q7}
        sub             sp,  sp,  #32          // cost
        mov             r3,  #8
        vmov.u16        q1,  #0                // q0-q1   sum_diag[0]
        vmov.u16        q3,  #0                // q2-q3   sum_diag[1]
        vmov.u16        q5,  #0                // q4-q5   sum_hv[0-1]
        vmov.u16        q8,  #0                // q6,d16  sum_alt[0]
                                               // q7,d17  sum_alt[1]
        vmov.u16        q9,  #0                // q9,d22  sum_alt[2]
        vmov.u16        q11, #0
        vmov.u16        q10, #0                // q10,d23 sum_alt[3]


.irpc i, 01234567
        vld1.8          {d30}, [r0, :64], r1
        vmov.u8         d31, #128
        vsubl.u8        q15, d30, d31          // img[x] - 128
        vmov.u16        q14, #0

.if \i == 0
        vmov            q0,  q15               // sum_diag[0]
.else
        vext.8          q12, q14, q15, #(16-2*\i)
        vext.8          q13, q15, q14, #(16-2*\i)
        vadd.i16        q0,  q0,  q12          // sum_diag[0]
        vadd.i16        q1,  q1,  q13          // sum_diag[0]
.endif
        vrev64.16       q13, q15
        vswp            d26, d27               // [-x]
.if \i == 0
        vmov            q2,  q13               // sum_diag[1]
.else
        vext.8          q12, q14, q13, #(16-2*\i)
        vext.8          q13, q13, q14, #(16-2*\i)
        vadd.i16        q2,  q2,  q12          // sum_diag[1]
        vadd.i16        q3,  q3,  q13          // sum_diag[1]
.endif

        vpadd.u16       d26, d30, d31          // [(x >> 1)]
        vmov.u16        d27, #0
        vpadd.u16       d24, d26, d28
        vpadd.u16       d24, d24, d28          // [y]
        vmov.u16        r12, d24[0]
        vadd.i16        q5,  q5,  q15          // sum_hv[1]
.if \i < 4
        vmov.16         d8[\i],   r12          // sum_hv[0]
.else
        vmov.16         d9[\i-4], r12          // sum_hv[0]
.endif

.if \i == 0
        vmov.u16        q6,  q13               // sum_alt[0]
.else
        vext.8          q12, q14, q13, #(16-2*\i)
        vext.8          q14, q13, q14, #(16-2*\i)
        vadd.i16        q6,  q6,  q12          // sum_alt[0]
        vadd.i16        d16, d16, d28          // sum_alt[0]
.endif
        vrev64.16       d26, d26               // [-(x >> 1)]
        vmov.u16        q14, #0
.if \i == 0
        vmov            q7,  q13               // sum_alt[1]
.else
        vext.8          q12, q14, q13, #(16-2*\i)
        vext.8          q13, q13, q14, #(16-2*\i)
        vadd.i16        q7,  q7,  q12          // sum_alt[1]
        vadd.i16        d17, d17, d26          // sum_alt[1]
.endif

.if \i < 6
        vext.8          q12, q14, q15, #(16-2*(3-(\i/2)))
        vext.8          q13, q15, q14, #(16-2*(3-(\i/2)))
        vadd.i16        q9,  q9,  q12          // sum_alt[2]
        vadd.i16        d22, d22, d26          // sum_alt[2]
.else
        vadd.i16        q9,  q9,  q15          // sum_alt[2]
.endif
.if \i == 0
        vmov            q10, q15               // sum_alt[3]
.elseif \i == 1
        vadd.i16        q10, q10, q15          // sum_alt[3]
.else
        vext.8          q12, q14, q15, #(16-2*(\i/2))
        vext.8          q13, q15, q14, #(16-2*(\i/2))
        vadd.i16        q10, q10, q12          // sum_alt[3]
        vadd.i16        d23, d23, d26          // sum_alt[3]
.endif
.endr

        vmov.u32        q15, #105

        vmull.s16       q12, d8,  d8           // sum_hv[0]*sum_hv[0]
        vmlal.s16       q12, d9,  d9
        vmull.s16       q13, d10, d10          // sum_hv[1]*sum_hv[1]
        vmlal.s16       q13, d11, d11
        vadd.s32        d8,  d24, d25
        vadd.s32        d9,  d26, d27
        vpadd.s32       d8,  d8,  d9           // cost[2,6] (s16, s17)
        vmul.i32        d8,  d8,  d30          // cost[2,6] *= 105

        vrev64.16       q1,  q1
        vrev64.16       q3,  q3
        vext.8          q1,  q1,  q1,  #10     // sum_diag[0][14-n]
        vext.8          q3,  q3,  q3,  #10     // sum_diag[1][14-n]

        vstr            s16, [sp, #2*4]        // cost[2]
        vstr            s17, [sp, #6*4]        // cost[6]

        movrel_local    r12, div_table
        vld1.16         {q14}, [r12, :128]

        vmull.s16       q5,  d0,  d0           // sum_diag[0]*sum_diag[0]
        vmull.s16       q12, d1,  d1
        vmlal.s16       q5,  d2,  d2
        vmlal.s16       q12, d3,  d3
        vmull.s16       q0,  d4,  d4           // sum_diag[1]*sum_diag[1]
        vmull.s16       q1,  d5,  d5
        vmlal.s16       q0,  d6,  d6
        vmlal.s16       q1,  d7,  d7
        vmovl.u16       q13, d28               // div_table
        vmovl.u16       q14, d29
        vmul.i32        q5,  q5,  q13          // cost[0]
        vmla.i32        q5,  q12, q14
        vmul.i32        q0,  q0,  q13          // cost[4]
        vmla.i32        q0,  q1,  q14
        vadd.i32        d10, d10, d11
        vadd.i32        d0,  d0,  d1
        vpadd.i32       d0,  d10, d0           // cost[0,4] = s0,s1

        movrel_local    r12, alt_fact
        vld1.16         {d29, d30, d31}, [r12, :64] // div_table[2*m+1] + 105

        vstr            s0,  [sp, #0*4]        // cost[0]
        vstr            s1,  [sp, #4*4]        // cost[4]

        vmovl.u16       q13, d29               // div_table[2*m+1] + 105
        vmovl.u16       q14, d30
        vmovl.u16       q15, d31

.macro cost_alt dest, s1, s2, s3, s4, s5, s6
        vmull.s16       q1,  \s1, \s1          // sum_alt[n]*sum_alt[n]
        vmull.s16       q2,  \s2, \s2
        vmull.s16       q3,  \s3, \s3
        vmull.s16       q5,  \s4, \s4          // sum_alt[n]*sum_alt[n]
        vmull.s16       q12, \s5, \s5
        vmull.s16       q6,  \s6, \s6          // q6 overlaps the first \s1-\s2 here
        vmul.i32        q1,  q1,  q13          // sum_alt[n]^2*fact
        vmla.i32        q1,  q2,  q14
        vmla.i32        q1,  q3,  q15
        vmul.i32        q5,  q5,  q13          // sum_alt[n]^2*fact
        vmla.i32        q5,  q12, q14
        vmla.i32        q5,  q6,  q15
        vadd.i32        d2,  d2,  d3
        vadd.i32        d3,  d10, d11
        vpadd.i32       \dest, d2, d3          // *cost_ptr
.endm
        cost_alt        d14, d12, d13, d16, d14, d15, d17 // cost[1], cost[3]
        cost_alt        d15, d18, d19, d22, d20, d21, d23 // cost[5], cost[7]
        vstr            s28, [sp, #1*4]        // cost[1]
        vstr            s29, [sp, #3*4]        // cost[3]

        mov             r0,  #0                // best_dir
        vmov.32         r1,  d0[0]             // best_cost
        mov             r3,  #1                // n

        vstr            s30, [sp, #5*4]        // cost[5]
        vstr            s31, [sp, #7*4]        // cost[7]

        vmov.32         r12, d14[0]

.macro find_best s1, s2, s3
.ifnb \s2
        vmov.32         lr,  \s2
.endif
        cmp             r12, r1                // cost[n] > best_cost
        itt             gt
        movgt           r0,  r3                // best_dir = n
        movgt           r1,  r12               // best_cost = cost[n]
.ifnb \s2
        add             r3,  r3,  #1           // n++
        cmp             lr,  r1                // cost[n] > best_cost
        vmov.32         r12, \s3
        itt             gt
        movgt           r0,  r3                // best_dir = n
        movgt           r1,  lr                // best_cost = cost[n]
        add             r3,  r3,  #1           // n++
.endif
.endm
        find_best       d14[0], d8[0], d14[1]
        find_best       d14[1], d0[1], d15[0]
        find_best       d15[0], d8[1], d15[1]
        find_best       d15[1]

        eor             r3,  r0,  #4           // best_dir ^4
        ldr             r12, [sp, r3, lsl #2]
        sub             r1,  r1,  r12          // best_cost - cost[best_dir ^ 4]
        lsr             r1,  r1,  #10
        str             r1,  [r2]              // *var

        add             sp,  sp,  #32
        vpop            {q4-q7}
        pop             {pc}
endfunc