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-rw-r--r--contrib/pngneon/png_read_filter_row_neon.s1170
1 files changed, 1170 insertions, 0 deletions
diff --git a/contrib/pngneon/png_read_filter_row_neon.s b/contrib/pngneon/png_read_filter_row_neon.s
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+#; Copyright (c) 2010-2011, Code Aurora Forum. All rights reserved.
+#;
+#; Redistribution and use in source and binary forms, with or without
+#; modification, are permitted provided that the following conditions are
+#; met:
+#; * Redistributions of source code must retain the above copyright
+#; notice, this list of conditions and the following disclaimer.
+#; * 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.
+#; * Neither the name of Code Aurora Forum, Inc. nor the names of its
+#; contributors may be used to endorse or promote products derived
+#; from this software without specific prior written permission.
+#;
+#; THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
+#; WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+#; MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT
+#; 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.
+
+#;==============================================================================
+
+ .code 32 @; Code is ARM ISA
+#;==============================================================================
+
+ .global png_read_filter_row_neon
+
+#;==============================================================================
+#; INPUTS: r0 rowbytes: number of bytes in current row
+#; r1 pixel_depth: number of bits per pixel
+#; r2 row: pointer to start of current row
+#; r3 prev_row: pointer to start of previous row
+#; [sp,#0] filter: filter type
+#;
+#; NOTE: Don't touch r5-r11
+#;==============================================================================
+.balign 32
+.type png_read_filter_row_neon, %function
+png_read_filter_row_neon:
+
+ ldr r12,[sp,#0]
+
+ cmp r12,#0
+ beq DONE
+
+ cmp r12,#1
+ beq sub_filter
+
+ cmp r12,#2
+ beq up_filter
+
+ cmp r12,#3
+ beq avg_filter
+
+ cmp r12,#4
+ beq paeth_filter
+
+ b DONE
+
+ #;; ---------------
+ #;; SUB filter type
+ #;; ---------------
+
+
+sub_filter:
+
+ stmdb sp!, {r4}
+
+ add r1,r1,#7 @; bpp = bytes per pixel
+ lsr r1,r1,#3 @; = (pixel_depth + 7) >> 3
+ mov r12,r1
+
+ #;; r0 = rowbytes
+ #;; r1 = loop counter = bpp (initially)
+ #;; r2 = row pointer
+ #;; r12 = bpp = loop/pointer increment value
+
+ cmp r1,r0
+ beq sub_filter_exit @; exit if bpp == rowbytes
+
+ cmp r12,#1
+ beq sub_filter_1bpp
+
+ cmp r12,#2
+ beq sub_filter_2bpp
+
+ cmp r12,#3
+ beq sub_filter_3bpp
+
+ cmp r12,#4
+ beq sub_filter_4bpp
+
+ cmp r12,#6
+ beq sub_filter_6bpp
+
+ cmp r12,#8
+ beq sub_filter_8bpp
+
+sub_filter_exit:
+ b sub_filter_DONE @; return
+
+
+sub_filter_1bpp:
+
+ #;; ----------------------------
+ #;; SUB filter, 1 byte per pixel
+ #;; ----------------------------
+
+ lsrs r4,r0,#4 @; r1 = floor(rowbytes/4)
+ @; = iteration count for loop16
+ beq sub_filter_1bpp_16bytes_done
+
+ vmov.i8 d21, #0
+ vld1.8 {d16,d17}, [r2] @; load 16 pixels
+ @; d16 = a b c d e f g h
+ @; d17 = i j k l m n o p
+
+ mov r1, #0
+sub_filter_1bpp_16bytes:
+
+
+
+
+ vshl.i64 d18, d16, #8 @; d18 = 0 a b c d e f g
+ vadd.i8 d18, d16, d18 @; d18 = a a+b b+c c+d d+e e+f f+g g+h
+
+ vshl.i64 d18, d18, #8 @; d18 = 0 a a+b b+c c+d d+e e+f f+g
+ vadd.i8 d18, d16, d18 @; d18 = a a+b a+b+c b+c+d c+d+e d+e+f e+f+g f+g+h
+
+ vshl.i64 d18, d18, #8 @; shift add continuously to propage the sum of previous
+ vadd.i8 d18, d16, d18 @; and current pixels
+
+ vshl.i64 d18, d18, #8
+ vadd.i8 d18, d16, d18
+
+ vshl.i64 d18, d18, #8
+ vadd.i8 d18, d16, d18
+
+ vshl.i64 d18, d18, #8
+ vadd.i8 d18, d16, d18
+
+ vshl.i64 d18, d18, #8
+ vadd.i8 d18, d16, d18 @; maximum data size for shift is 64 bits i.e. doubleword.
+ @; after computing thh value of all the pixels in the double word
+ @; extract the last computed value which will be used by
+ @; the next set of pixels (i.e next doubleword)
+ vext.8 d22, d18, d21, #7 @; extract the updated value of d18[7] i.e a+b+c+d+e+f+h
+ vadd.i8 d17, d17, d22 @; d17 = a+b+c+d+e+f+g+h+i j k l m n o p
+
+ vshl.i64 d19, d17, #8 @; continue shift-add as the first half
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #8
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #8
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #8
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #8
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #8
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #8
+ vadd.i8 d19, d17, d19
+
+ vst1.8 {d18,d19},[r2]! @; store the result back
+
+ add r1, r1, #16 @; add 16 to the loop counter(no of bytes completed)
+ subs r4,r4,#1 @; decrement iteration count
+ beq sub_filter_1bpp_16bytes_adjust
+
+
+ vext.8 d22, d19, d21, #7 @; more iterations to go
+ @; extract the last computed value
+ vld1.8 {d16,d17}, [r2] @; load the next 16 bytes
+ vadd.i8 d16, d16, d22 @; set up the input by adding the previous pixel
+ @; value to the input
+ b sub_filter_1bpp_16bytes
+
+sub_filter_1bpp_16bytes_adjust:
+
+ cmp r1, r0 @; no more pixels left .. exit
+ sub r2, r2, #1 @; more pixels remaining
+ @; r2 points to the current pixel adjust it
+ @; so that it points to the prev pixel for the below loop
+ beq sub_filter_DONE
+
+sub_filter_1bpp_16bytes_done:
+
+
+ vld1.8 {d0[0]},[r2]! @; load 1 byte (1 pixel) into D0[0]
+ @; increment row pointer
+sub_filter_1bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0 @;
+
+ vld1.8 {d2[0]},[r2] @; load 1 byte (current pixel) into D2[0]
+
+ vadd.i8 d0,d0,d2 @; vector add 1 byte of previous pixel with
+ @; 1 byte of current pixel
+ vst1.8 {d0[0]},[r2]! @; store 1 byte (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+
+ bne sub_filter_1bpp_loop @; loop back until loop counter == rowbytes
+
+ b sub_filter_DONE @; return
+
+ #;; -----------------------------
+ #;; SUB filter, 2 bytes per pixel
+ #;; -----------------------------
+sub_filter_2bpp:
+
+ lsrs r4,r0,#4 @; r1 = floor(rowbytes/4)
+ @; = iteration count for loop16
+ beq sub_filter_2bpp_16bytes_done
+
+ vmov.i8 d21, #0
+ vld1.8 {d16,d17}, [r2] @; load 16 bytes to q8
+ @; d16 = a b c d e f g h
+ @; d17 = i j k l m n o p
+ mov r1, #0
+sub_filter_2bpp_16bytes:
+
+ vshl.i64 d18, d16, #16 @; each pixel is 2bytes .. shift by 16 bits to get previous pixel
+ vadd.i8 d18, d16, d18 @; add to the current pixel
+
+ vshl.i64 d18, d18, #16 @; shift-add to propagate the computed sum as the case for 1bpp
+ vadd.i8 d18, d16, d18
+
+ vshl.i64 d18, d18, #16
+ vadd.i8 d18, d16, d18
+
+
+ vext.8 d22, d18, d21, #6 @; extract the last computed value (i.e. last 2 bytes)
+ vadd.i8 d17, d17, d22 @; add the last computed pixel to the input
+
+ vshl.i64 d19, d17, #16
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #16
+ vadd.i8 d19, d17, d19
+
+ vshl.i64 d19, d19, #16
+ vadd.i8 d19, d17, d19
+
+
+ vst1.8 {d18,d19},[r2]! @; store the result back
+
+
+ add r1, r1, #16 @; add 16 to the loop counter(no of bytes completed)
+ subs r4,r4,#1 @; decrement iteration count
+ beq sub_filter_2bpp_16bytes_adjust
+
+
+ vext.8 d22, d19, d21, #6 @; extract the last computed value
+ @; add the last computed pixel to the input
+ vld1.8 {d16,d17}, [r2]
+ vadd.i8 d16, d16, d22
+
+ b sub_filter_2bpp_16bytes
+
+
+sub_filter_2bpp_16bytes_adjust:
+
+ cmp r1, r0 @; no more pixels left .. exit
+ sub r2, r2, #2 @; more pixels remaining
+ @; r2 points to the current pixel adjust it
+ @; so that it points to the prev pixel for the below loop
+ beq sub_filter_DONE
+
+sub_filter_2bpp_16bytes_done:
+
+ vld1.16 {d0[0]},[r2]! @; load 2 bytes (1 pixel) into D0[0]
+ @; increment row pointer
+sub_filter_2bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0 @;
+
+ vld1.16 {d2[0]},[r2] @; load 2 bytes (current pixel) into D2[0]
+ vadd.i8 d0,d0,d2 @; vector add 2 bytes of previous pixel with
+ @; 2 bytes of current pixel
+ vst1.16 {d0[0]},[r2]! @; store 2 bytes (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+
+ bne sub_filter_2bpp_loop @; loop back until loop counter == rowbytes
+ @
+ b sub_filter_DONE @ ; return
+
+ #;; -----------------------------
+ #;; SUB filter, 3 bytes per pixel
+ #;; -----------------------------
+sub_filter_3bpp:
+ vld1.32 {d0[0]},[r2], r12 @; load 4 bytes (1 pixel + 1 extra byte) into D0[0]
+ @; increment row pointer by bpp
+sub_filter_3bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0 @;
+
+ vld1.32 {d2[0]},[r2] @; load 4 bytes (current pixel + 1 extra byte) into D2[0]
+ vadd.i8 d0,d0,d2 @; vector add 3 bytes of previous pixel with
+ @; 3 bytes of current pixel
+ vst1.16 {d0[0]},[r2]! @; store 2 bytes (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+ vst1.8 {d0[2]},[r2]! @; store 1 byte (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+
+ bne sub_filter_3bpp_loop @; loop back until loop counter == rowbytes
+
+ b sub_filter_DONE @; return
+
+ #;; -----------------------------
+ #;; SUB filter, 4 bytes per pixel
+ #;; -----------------------------
+sub_filter_4bpp:
+ vld1.32 {d0[0]},[r2]! @; load 4 bytes (1 pixel) into D0[0]
+ @; increment row pointer
+sub_filter_4bpp_loop: @
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0 @;
+
+
+ vld1.32 {d2[0]},[r2] @; load 4 bytes (current pixel) into D2[0]
+ vadd.i8 d0,d0,d2 @; vector add 4 bytes of previous pixel with
+ @; 4 bytes of current pixel
+ vst1.32 {d0[0]},[r2]! @; store 4 bytes (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+
+ bne sub_filter_4bpp_loop @; loop back until loop counter == rowbytes
+
+ b sub_filter_DONE @; return
+
+ #;; -----------------------------
+ #;; SUB filter, 6 bytes per pixel
+ #;; -----------------------------
+sub_filter_6bpp:
+ vld1.8 {d0},[r2],r12 @; load 8 bytes (1 pixel + 2 extra bytes) into D0
+ @; increment row pointer by bpp
+sub_filter_6bpp_loop: @
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0 @;
+
+ vld1.8 {d2},[r2] @; load 8 bytes (1 pixel + 2 extra bytes) into D2
+ vadd.i8 d0,d0,d2 @; vector add 6 bytes of previous pixel with
+ @; 6 bytes of current pixel
+ vst1.32 {d0[0]},[r2]! @; store 4 bytes (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+ vst1.16 {d0[2]},[r2]! @; store 2 bytes (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+
+ bne sub_filter_6bpp_loop @; loop back until loop counter == rowbytes
+
+ b sub_filter_DONE @; return
+
+ #;; -----------------------------
+ #;; SUB filter, 8 bytes per pixel
+ #;; -----------------------------
+sub_filter_8bpp:
+ vld1.8 {d0},[r2]! @; load 8 bytes (1 pixel) into D0
+ @; increment row pointer
+sub_filter_8bpp_loop: @
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0 @;
+ vld1.8 {d2},[r2] @; load 8 bytes (current pixel) into D2
+ vadd.i8 d0,d0,d2 @; vector add 8 bytes of previous pixel with
+ @; 8 bytes of current pixel
+ vst1.8 {d0},[r2]! @; store 8 bytes (updated pixel) back
+ @; into row pointer location and increment
+ @; row pointer
+
+
+ bne sub_filter_8bpp_loop @; loop back until loop counter == rowbytes
+ @
+ b sub_filter_DONE @ ; return
+
+sub_filter_DONE:
+
+ ldmia sp!, {r4}
+ bx r14
+
+ #;; --------------
+ #;; UP filter type
+ #;; --------------
+up_filter:
+
+ #;; r0 = rowbytes
+ #;; r1 = pixel_depth (not required for UP filter type)
+ #;; r2 = row pointer
+ #;; r3 = previous row pointer
+
+
+ lsrs r1,r0,#5 @; r1 = floor(rowbytes/32)
+ @; = iteration count for loop32
+ beq up_filter_32bytes_proc_done
+
+
+up_filter_32bytes_proc:
+
+
+ mov r12, r2
+
+ vld1.8 {q0},[r3]! @; load 32 bytes from previous
+ vld1.8 {q2},[r3]! @; row and increment pointer
+ @
+ @
+ vld1.8 {q1},[r12]! @; load 32 bytes from current row
+ vld1.8 {q3},[r12]! @
+ @
+ @
+ @
+ vadd.i8 q0,q0,q1 @; vector add of 16 bytes
+ vadd.i8 q2,q2,q3 @
+ @
+ @
+ @
+ vst1.8 {q0},[r2]! @; store 32 bytes to current row
+ vst1.8 {q2},[r2]! @
+ @; and increment pointer
+ sub r0,r0,#32 @; subtract 32 from rowbytes
+ subs r1,r1,#1 @; decrement iteration count
+ bne up_filter_32bytes_proc
+
+
+
+up_filter_32bytes_proc_done:
+
+ lsrs r1,r0,#4 @; r1 = floor(rowbytes/16)
+ @; = iteration count for loop16
+ beq up_filter_16bytes_proc_done
+
+up_filter_16bytes_proc:
+
+ vld1.8 {q0},[r3]! @; load 16 bytes from previous
+ @; row and increment pointer
+ vld1.8 {q1},[r2] @; load 16 bytes from current row
+ vadd.i8 q0,q0,q1 @; vector add of 16 bytes
+ vst1.8 {q0},[r2]! @; store 16 bytes to current row
+ @; and increment pointer
+ sub r0,r0,#16 @; subtract 16 from rowbytes
+ subs r1,r1,#1 @; decrement iteration count
+ bne up_filter_16bytes_proc
+
+up_filter_16bytes_proc_done:
+
+ lsrs r1,r0,#3 @; r1 = floor(rowbytes/8)
+ beq up_filter_8bytes_proc_done
+
+up_filter_8bytes_proc:
+
+ vld1.8 {d0},[r3]! @; load 8 bytes from previous
+ @; row and increment pointer
+ vld1.8 {d2},[r2] @; load 8 bytes from current row
+ vadd.i8 d0,d0,d2 @; vector add 8 bytes
+ vst1.8 {d0},[r2]! @; store 8 bytes to current row
+ @; and increment pointer
+ sub r0,r0,#8 @; subtract 8 from rowbytes
+
+up_filter_8bytes_proc_done:
+
+ lsrs r1,r0,#2 @; r1 = floor(rowbytes/4)
+ beq up_filter_4bytes_proc_done
+
+up_filter_4bytes_proc:
+
+ vld1.32 {d0[0]},[r3]! @; load 4 bytes from previous row
+ @; and increment pointer
+ vld1.32 {d2[0]},[r2] @; load 4 bytes from current row
+ vadd.i8 d0,d0,d2 @; vector add 4 bytes
+ vst1.32 {d0[0]},[r2]! @; store 4 bytes to current row
+ @; and increment pointer
+ sub r0,r0,#4 @; subtract 4 from rowbytes
+
+up_filter_4bytes_proc_done:
+
+ lsrs r1,r0,#1 @; r1 = floor(rowbytes/2)
+ beq up_filter_2bytes_proc_done
+
+up_filter_2bytes_proc:
+
+ vld1.16 {d0[0]},[r3]! @; load 2 bytes from previous row
+ @; and increment pointer
+ vld1.16 {d2[0]},[r2] @; load 2 bytes from current row
+ vadd.i8 d0,d0,d2 @; vector add 2 bytes
+ vst1.16 {d0[0]},[r2]! @; store 2 bytes to current row
+ @; and increment pointer
+ sub r0,r0,#2 @; subtract 2 from rowbytes
+
+up_filter_2bytes_proc_done:
+
+ cmp r0,#0
+ beq up_filter_1byte_proc_done
+
+up_filter_1byte_proc:
+
+ vld1.8 {d0[0]},[r3]! @; load 1 byte from previous row
+ @; and increment pointer
+ vld1.8 {d2[0]},[r2] @; load 1 byte from current row
+ vadd.i8 d0,d0,d2 @; vector add 1 byte
+ vst1.8 {d0[0]},[r2]! @; store 1 byte to current row
+ @; and increment pointer
+up_filter_1byte_proc_done:
+
+ b DONE
+
+ #;; ---------------
+ #;; AVG filter type
+ #;; ---------------
+avg_filter:
+
+ add r1,r1,#7 @; bpp = byptes per pixel
+ lsr r1,r1,#3 @; = (pixel_depth + 7) >> 3
+ mov r12,r1
+
+ #;; r0 = rowbytes
+ #;; r1 = loop counter = bpp (initially)
+ #;; r2 = row pointer
+ #;; r3 = previous row pointer
+ #;; r12 = bpp = loop/pointer increment value
+
+ cmp r12,#1
+ beq avg_filter_1bpp
+
+ cmp r12,#2
+ beq avg_filter_2bpp
+
+ cmp r12,#3
+ beq avg_filter_3bpp
+
+ cmp r12,#4
+ beq avg_filter_4bpp
+
+ cmp r12,#6
+ beq avg_filter_6bpp
+
+ cmp r12,#8
+ beq avg_filter_8bpp
+
+avg_filter_exit:
+ b DONE @; return
+
+ #;; ----------------------------
+ #;; AVG filter, 1 byte per pixel
+ #;; ----------------------------
+avg_filter_1bpp:
+
+ cmp r1,r0
+
+ vld1.8 {d0[0]},[r2] @; load 1 byte (pixel x) from curr
+ @; row into d0[0]
+ vld1.8 {d1[0]},[r3]! @; load 1 byte (pixel b) from prev
+ @; row into d1[0]
+ @; increment prev row pointer
+ vsra.u8 d0,d1,#1 @; shift right pixel b by 1 and add
+ @; to pixel x
+ vst1.8 {d0[0]},[r2]! @; store 1 byte (updated pixel x)
+ @; increment curr row pointer
+ @; updated pixel x is now pixel a
+ beq DONE
+
+avg_filter_1bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ vld1.8 {d2[0]},[r2] @; load 1 byte (pixel x) from curr
+ @; row into d2[0]
+ vld1.8 {d1[0]},[r3]! @; load 1 byte (pixel b) from prev
+ @; row into d1[0]
+ vaddl.u8 q2,d0,d1 @; q2 = (pixel a + pixel b)
+ vshrn.i16 d1,q2,#1 @; d1[0] = (a + b)/2
+ vadd.i8 d0,d2,d1 @; d0[0] = x + ((a + b)/2)
+ vst1.8 {d0[0]},[r2]! @; store 1 byte (updated pixel x)
+ @; increment curr row pointer
+ bne avg_filter_1bpp_loop
+
+ b DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -----------------------------
+ #;; AVG filter, 2 bytes per pixel
+ #;; -----------------------------
+avg_filter_2bpp:
+
+ cmp r1,r0
+
+ vld1.16 {d0[0]},[r2] @; load 2 bytes (pixel x) from curr
+ @; row into d0[0]
+ vld1.16 {d1[0]},[r3]! @; load 2 bytes (pixel b) from prev
+ @; row into d1[0]
+ @; increment prev row pointer
+ vsra.u8 d0,d1,#1 @; shift right pixel b by 1 and add
+ @; to pixel x
+ vst1.16 {d0[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ @; updated pixel x is now pixel a
+ beq DONE
+
+avg_filter_2bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ vld1.16 {d2[0]},[r2] @; load 2 bytes (pixel x) from curr
+ @; row into d2[0]
+ vld1.16 {d1[0]},[r3]! @; load 2 bytes (pixel b) from prev
+ @; row into d1[0]
+ vaddl.u8 q2,d0,d1 @; q2 = (pixel a + pixel b)
+ vshrn.i16 d1,q2,#1 @; d1[0] = (a + b)/2
+ vadd.i8 d0,d2,d1 @; d0[0] = x + ((a + b)/2)
+ vst1.16 {d0[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+
+ bne avg_filter_2bpp_loop
+
+ b DONE @; exit loop when
+ @; loop counter == rowbytes
+
+ #;; -----------------------------
+ #;; AVG filter, 3 bytes per pixel
+ #;; -----------------------------
+avg_filter_3bpp:
+
+ cmp r1,r0
+
+ vld1.32 {d0[0]},[r2] @; load 4 bytes (pixel x + 1 extra
+ @; byte) from curr row into d0[0]
+ vld1.32 {d1[0]},[r3],r12 @; load 4 bytes (pixel b + 1 extra
+ @; byte) from prev row into d1[0]
+ @; increment prev row pointer
+ vsra.u8 d0,d1,#1 @; shift right pixel b by 1 and add
+ @; to pixel x
+ vst1.16 {d0[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ vst1.8 {d0[2]},[r2]! @; store 1 byte (updated pixel x)
+ @; increment curr row pointer
+ @; updated pixel x is now pixel a
+ beq DONE
+
+avg_filter_3bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+ vld1.32 {d2[0]},[r2] @; load 4 bytes (pixel x + 1 extra
+ @; byte) from curr row into d2[0]
+ vld1.32 {d1[0]},[r3],r12 @; load 4 bytes (pixel b + 1 extra
+ @; byte) from prev row into d1[0]
+ vaddl.u8 q2,d0,d1 @; q2 = (pixel a + pixel b)
+ vshrn.i16 d1,q2,#1 @; d1[0] = (a + b)/2
+ vadd.i8 d0,d2,d1 @; d0[0] = x + ((a + b)/2)
+ vst1.16 {d0[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ vst1.8 {d0[2]},[r2]! @; store 1 byte (updated pixel x)
+ @; increment curr row pointer
+
+ bne avg_filter_3bpp_loop
+
+ b DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -----------------------------
+ #;; AVG filter, 4 bytes per pixel
+ #;; -----------------------------
+avg_filter_4bpp:
+
+ cmp r1,r0
+
+ vld1.32 {d0[0]},[r2] @; load 4 bytes (pixel x) from curr
+ @; row into d0[0]
+ vld1.32 {d1[0]},[r3]! @; load 4 bytes (pixel b) from prev
+ @; row into d1[0]
+ @; increment prev row pointer
+ vsra.u8 d0,d1,#1 @; shift right pixel b by 1 and add
+ @; to pixel x
+ vst1.32 {d0[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ @; updated pixel x is now pixel a
+ beq DONE
+
+avg_filter_4bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ vld1.32 {d2[0]},[r2] @; load 4 bytes (pixel x) from curr
+ @; row into d2[0]
+ vld1.32 {d1[0]},[r3]! @; load 4 bytes (pixel b) from prev
+ @; row into d1[0]
+ vaddl.u8 q2,d0,d1 @; q2 = (pixel a + pixel b)
+ vshrn.i16 d1,q2,#1 @; d1[0] = (a + b)/2
+ vadd.i8 d0,d2,d1 @; d0[0] = x + ((a + b)/2)
+ vst1.32 {d0[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ bne avg_filter_4bpp_loop
+
+ b DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -----------------------------
+ #;; AVG filter, 6 bytes per pixel
+ #;; -----------------------------
+avg_filter_6bpp:
+
+ cmp r1,r0
+
+ vld1.8 {d0},[r2] @; load 8 bytes (pixel x + 2 extra
+ @; bytes) from curr row into d0
+ vld1.8 {d1},[r3],r12 @; load 8 bytes (pixel b + 2 extra
+ @; bytes) from prev row into d1
+ @; increment prev row pointer
+ vsra.u8 d0,d1,#1 @; shift right pixel b by 1 and add
+ @; to pixel x
+ vst1.32 {d0[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ @; updated pixel x is now pixel a
+ vst1.16 {d0[2]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ @; updated pixel x is now pixel a
+ beq DONE
+
+avg_filter_6bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ vld1.8 {d2},[r2] @; load 8 bytes (pixel x + 2 extra
+ @; bytes) from curr row into d2
+ vld1.8 {d1},[r3],r12 @; load 8 bytes (pixel b + 2 extra
+ @; bytes) from prev row into d1
+ vaddl.u8 q2,d0,d1 @; q2 = (pixel a + pixel b)
+ vshrn.i16 d1,q2,#1 @; d1 = (a + b)/2
+ vadd.i8 d0,d2,d1 @; d0 = x + ((a + b)/2)
+ vst1.32 {d0[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ vst1.16 {d0[2]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ bne avg_filter_6bpp_loop
+
+ b DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -----------------------------
+ #;; AVG filter, 8 bytes per pixel
+ #;; -----------------------------
+avg_filter_8bpp:
+
+ cmp r1,r0
+
+ vld1.8 {d0},[r2] @; load 8 bytes (pixel x) from curr
+ @; row into d0
+ vld1.8 {d1},[r3]! @; load 8 bytes (pixel b) from prev
+ @; row into d1
+ @; increment prev row pointer
+ vsra.u8 d0,d1,#1 @; shift right pixel b by 1 and add
+ @; to pixel x
+ vst1.8 {d0},[r2]! @; store 8 bytes (updated pixel x)
+ @; increment curr row pointer
+ @; updated pixel x is now pixel a
+ beq DONE
+avg_filter_8bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ vld1.8 {d2},[r2] @; load 8 bytes (pixel x) from curr
+ @; row into d2
+ vld1.8 {d1},[r3]! @; load 8 bytes (pixel b) from prev
+ @; row into d1
+ vaddl.u8 q2,d0,d1 @; q2 = (pixel a + pixel b)
+ vshrn.i16 d1,q2,#1 @; d1 = (a + b)/2
+ vadd.i8 d0,d2,d1 @; d0 = x + ((a + b)/2)
+ vst1.8 {d0},[r2]! @; store 8 bytes (updated pixel x)
+ @; increment curr row pointer
+ bne avg_filter_8bpp_loop
+
+ b DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -----------------
+ #;; PAETH filter type
+ #;; -----------------
+paeth_filter:
+
+ VPUSH {q4-q7}
+ add r1,r1,#7 @; bpp = bytes per pixel
+ lsr r1,r1,#3 @; = (pixel_depth + 7) >> 3
+ mov r12,r1
+
+ #;; r0 = rowbytes
+ #;; r1 = loop counter = bpp (initially)
+ #;; r2 = row pointer
+ #;; r3 = previous row pointer
+ #;; r12 = bpp = loop/pointer increment value
+
+
+ cmp r12,#1
+ beq paeth_filter_1bpp
+
+ cmp r12,#2
+ beq paeth_filter_2bpp
+
+ cmp r12,#3
+ beq paeth_filter_3bpp
+
+ cmp r12,#4
+ beq paeth_filter_4bpp
+
+ cmp r12,#6
+ beq paeth_filter_6bpp
+
+ cmp r12,#8
+ beq paeth_filter_8bpp
+
+paeth_filter_exit:
+ b paeth_filter_DONE @; return
+
+ #;; ------------------------------
+ #;; PAETH filter, 1 byte per pixel
+ #;; ------------------------------
+paeth_filter_1bpp:
+
+ cmp r1, r0
+
+ vld1.8 {d0[0]},[r2] @; load 1 byte (pixel x) from curr
+ @; row into d0[0]
+ vld1.8 {d1[0]},[r3]! @; load 1 byte (pixel b) from prev
+ @; row into d1[0]
+ @; increment prev row pointer
+ vadd.i8 d2,d0,d1 @; d2 = x + b = updated pixel x
+ vst1.8 {d2[0]},[r2]! @; store 1 byte (updated pixel x)
+ @; increment curr row pointer
+
+ beq paeth_filter_DONE
+
+paeth_filter_1bpp_loop:
+ add r1,r1,r12 @; increment curr row pointer
+ cmp r1,r0
+
+
+ #;; d1[0] = c (b in the previous loop iteration)
+ #;; d2[0] = a (x in the previous loop iteration)
+ vld1.8 {d3[0]},[r3]! @; load 1 byte (pixel b) from prev
+ @; row into d3[0]
+ vld1.8 {d0[0]},[r2] @; load 1 byte (pixel x) from curr
+ @; row into d0[0]
+ vshll.u8 q4,d1,#1 @; q4 = c<<1 = 2c
+ vabdl.u8 q3,d2,d1 @; q3 = pb = abs(a - c)
+ vabdl.u8 q2,d3,d1 @; q2 = pa = abs(b - c)
+ vaddl.u8 q5,d2,d3 @; q5 = a + b
+ vabd.u16 q4,q5,q4 @; q4 = pc = abs(a + b - 2c)
+
+ vcle.s16 q5,q2,q3 @; q5 = (pa <= pb)
+ vcle.s16 q6,q2,q4 @; q6 = (pa <= pc)
+ vand q5,q5,q6 @; q5 = ((pa <= pb) && (pa <= pc))
+ vcle.s16 q7,q3,q4 @; q7 = (pb <= pc)
+ vshrn.u16 d10,q5,#8 @; d10 = ((pa <= pb) && (pa <= pc))
+ vshrn.u16 d14,q7,#8 @; d14 = (pb <= pc)
+ @
+ vand d2,d2,d10 @; d2 = a where 1, 0 where 0
+ vbsl d14,d3,d1 @; d14 = b where 1, c where 0
+ vmvn d10,d10 @; invert d10
+ vand d14,d14,d10 @; d14 = b/c where 1, 0 where 0
+ vadd.i8 d2,d2,d14 @; d2 = p = a/b/c where appropriate
+ vadd.i8 d2,d2,d0 @; d2 = x + p (updated pixel x)
+ vmov d1,d3 @; d1 = b (c for next iteration)
+ vst1.8 {d2[0]},[r2]! @; store 1 byte (updated pixel x)
+
+
+ bne paeth_filter_1bpp_loop
+
+ b paeth_filter_DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -------------------------------
+ #;; PAETH filter, 2 bytes per pixel
+ #;; -------------------------------
+paeth_filter_2bpp:
+
+ cmp r1, r0
+
+ vld1.16 {d0[0]},[r2] @; load 2 bytes (pixel x) from curr
+ @; row into d0[0]
+ vld1.16 {d1[0]},[r3]! @; load 2 bytes (pixel b) from prev
+ @; row into d1[0]
+ @; increment prev row pointer
+ vadd.i8 d2,d0,d1 @; d2 = x + b = updated pixel x
+ vst1.16 {d2[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ beq paeth_filter_DONE
+
+paeth_filter_2bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+ #;; d1[0] = c (b in the previous loop iteration)
+ #;; d2[0] = a (x in the previous loop iteration)
+ vld1.16 {d3[0]},[r3]! @; load 2 bytes (pixel b) from prev
+ @; row into d3[0]
+ vld1.16 {d0[0]},[r2] @; load 2 bytes (pixel x) from curr
+ @; row into d0[0]
+ vshll.u8 q4,d1,#1 @; q4 = c<<1 = 2c
+ vabdl.u8 q3,d2,d1 @; q3 = pb = abs(a - c)
+ vabdl.u8 q2,d3,d1 @; q2 = pa = abs(b - c)
+ vaddl.u8 q5,d2,d3 @; q5 = a + b
+ vabd.u16 q4,q5,q4 @; q4 = pc = abs(a + b - 2c)
+
+ vcle.s16 q5,q2,q3 @; q5 = (pa <= pb)
+ vcle.s16 q6,q2,q4 @; q6 = (pa <= pc)
+ vand q5,q5,q6 @; q5 = ((pa <= pb) && (pa <= pc))
+ vcle.s16 q7,q3,q4 @; q7 = (pb <= pc)
+ vshrn.u16 d10,q5,#8 @; d10 = ((pa <= pb) && (pa <= pc))
+ vshrn.u16 d14,q7,#8 @; d14 = (pb <= pc)
+
+ vand d2,d2,d10 @; d2 = a where 1, 0 where 0
+ vbsl d14,d3,d1 @; d14 = b where 1, c where 0
+ vmvn d10,d10 @; invert d10
+ vand d14,d14,d10 @; d14 = b/c where 1, 0 where 0
+ vadd.i8 d2,d2,d14 @; d2 = p = a/b/c where appropriate
+ vadd.i8 d2,d2,d0 @; d2 = x + p (updated pixel x)
+ vmov d1,d3 @; d1 = b (c for next iteration)
+ vst1.16 {d2[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ bne paeth_filter_2bpp_loop
+
+ b paeth_filter_DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -------------------------------
+ #;; PAETH filter, 3 bytes per pixel
+ #;; -------------------------------
+paeth_filter_3bpp:
+
+ cmp r1, r0
+
+ vld1.32 {d0[0]},[r2] @; load 4 bytes (pixel x + 1 extra
+ @; byte) from curr row into d0[0]
+ vld1.32 {d1[0]},[r3],r12 @; load 4 bytes (pixel b + 1 extra
+ @; byte) from prev row into d1[0]
+ @; increment prev row pointer
+ vadd.i8 d2,d0,d1 @; d2 = x + b = updated pixel x
+ vst1.16 {d2[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ vst1.8 {d2[2]},[r2]! @; store 1 byte (updated pixel x)
+ @; increment curr row pointer
+ beq paeth_filter_DONE
+
+paeth_filter_3bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ #;; d1[0] = c (b in the previous loop iteration)
+ #;; d2[0] = a (x in the previous loop iteration)
+ vld1.32 {d3[0]},[r3],r12 @; load 4 bytes (pixel b + 1 extra
+ @; byte) from prev row into d3[0]
+ vld1.32 {d0[0]},[r2] @; load 4 bytes (pixel x + 1 extra
+ @; byte) from curr row into d0[0]
+ vshll.u8 q4,d1,#1 @; q4 = c<<1 = 2c
+ vabdl.u8 q3,d2,d1 @; q3 = pb = abs(a - c)
+ vabdl.u8 q2,d3,d1 @; q2 = pa = abs(b - c)
+ vaddl.u8 q5,d2,d3 @; q5 = a + b
+ vabd.u16 q4,q5,q4 @; q4 = pc = abs(a + b - 2c)
+ @
+ vcle.s16 q5,q2,q3 @; q5 = (pa <= pb)
+ vcle.s16 q6,q2,q4 @; q6 = (pa <= pc)
+ vand q5,q5,q6 @; q5 = ((pa <= pb) && (pa <= pc))
+ vcle.s16 q7,q3,q4 @; q7 = (pb <= pc)
+ vshrn.u16 d10,q5,#8 @; d10 = ((pa <= pb) && (pa <= pc))
+ vshrn.u16 d14,q7,#8 @; d14 = (pb <= pc)
+ @
+ vand d2,d2,d10 @; d2 = a where 1, 0 where 0
+ vbsl d14,d3,d1 @; d14 = b where 1, c where 0
+ vmvn d10,d10 @; invert d10
+ vand d14,d14,d10 @; d14 = b/c where 1, 0 where 0
+ vadd.i8 d2,d2,d14 @; d2 = p = a/b/c where appropriate
+ vadd.i8 d2,d2,d0 @; d2 = x + p (updated pixel x)
+ vmov d1,d3 @; d1 = b (c for next iteration)
+ vst1.16 {d2[0]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ vst1.8 {d2[2]},[r2]! @; store 1 byte (updated pixel x)
+ @; increment curr row pointer
+ bne paeth_filter_3bpp_loop
+
+ b paeth_filter_DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -------------------------------
+ #;; PAETH filter, 4 bytes per pixel
+ #;; -------------------------------
+paeth_filter_4bpp:
+
+ cmp r1, r0
+
+ vld1.32 {d0[0]},[r2] @; load 4 bytes (pixel x) from curr
+ @; row into d0[0]
+ vld1.32 {d1[0]},[r3]! @; load 4 bytes (pixel b) from prev
+ @; row into d1[0]
+ @; increment prev row pointer
+ vadd.i8 d2,d0,d1 @; d2 = x + b = updated pixel x
+ vst1.32 {d2[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ beq paeth_filter_DONE
+
+paeth_filter_4bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ #;; d1[0] = c (b in the previous loop iteration)
+ #;; d2[0] = a (x in the previous loop iteration)
+ vld1.32 {d3[0]},[r3]! @; load 4 bytes (pixel b) from prev
+ @; row into d3[0]
+ vld1.32 {d0[0]},[r2] @; load 4 bytes (pixel x) from curr
+ @; row into d0[0]
+ vshll.u8 q4,d1,#1 @; q4 = c<<1 = 2c
+ vabdl.u8 q3,d2,d1 @; q3 = pb = abs(a - c)
+ vabdl.u8 q2,d3,d1 @; q2 = pa = abs(b - c)
+ vaddl.u8 q5,d2,d3 @; q5 = a + b
+ vabd.u16 q4,q5,q4 @; q4 = pc = abs(a + b - 2c)
+ @
+ vcle.s16 q5,q2,q3 @; q5 = (pa <= pb)
+ vcle.s16 q6,q2,q4 @; q6 = (pa <= pc)
+ vand q5,q5,q6 @; q5 = ((pa <= pb) && (pa <= pc))
+ vcle.s16 q7,q3,q4 @; q7 = (pb <= pc)
+ vshrn.u16 d10,q5,#8 @; d10 = ((pa <= pb) && (pa <= pc))
+ vshrn.u16 d14,q7,#8 @; d14 = (pb <= pc)
+ @
+ vand d2,d2,d10 @; d2 = a where 1, 0 where 0
+ vbsl d14,d3,d1 @; d14 = b where 1, c where 0
+ vmvn d10,d10 @; invert d10
+ vand d14,d14,d10 @; d14 = b/c where 1, 0 where 0
+ vadd.i8 d2,d2,d14 @; d2 = p = a/b/c where appropriate
+ vadd.i8 d2,d2,d0 @; d2 = x + p (updated pixel x)
+ vmov d1,d3 @; d1 = b (c for next iteration)
+ vst1.32 {d2[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ bne paeth_filter_4bpp_loop
+
+ b paeth_filter_DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -------------------------------
+ #;; PAETH filter, 6 bytes per pixel
+ #;; -------------------------------
+paeth_filter_6bpp:
+ cmp r1, r0
+
+ vld1.8 {d0},[r2] @; load 8 bytes (pixel x + 2 extra
+ @; bytes) from curr row into d0
+ vld1.8 {d1},[r3],r12 @; load 8 bytes (pixel b + 2 extra
+ @; bytes) from prev row into d1
+ @; increment prev row pointer
+ vadd.i8 d2,d0,d1 @; d2 = x + b = updated pixel x
+ vst1.32 {d2[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ vst1.16 {d2[2]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ beq paeth_filter_DONE
+
+paeth_filter_6bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ #;; d1[0] = c (b in the previous loop iteration)
+ #;; d2[0] = a (x in the previous loop iteration)
+ vld1.8 {d3},[r3],r12 @; load 8 bytes (pixel b + 2 extra
+ @; bytes) from prev row into d3
+ vld1.8 {d0},[r2] @; load 8 bytes (pixel x + 2 extra
+ @; bytes) from curr row into d0
+ vshll.u8 q4,d1,#1 @; q4 = c<<1 = 2c
+ vabdl.u8 q3,d2,d1 @; q3 = pb = abs(a - c)
+ vabdl.u8 q2,d3,d1 @; q2 = pa = abs(b - c)
+ vaddl.u8 q5,d2,d3 @; q5 = a + b
+ vabd.u16 q4,q5,q4 @; q4 = pc = abs(a + b - 2c)
+
+ vcle.s16 q5,q2,q3 @; q5 = (pa <= pb)
+ vcle.s16 q6,q2,q4 @; q6 = (pa <= pc)
+ vand q5,q5,q6 @; q5 = ((pa <= pb) && (pa <= pc))
+ vcle.s16 q7,q3,q4 @; q7 = (pb <= pc)
+ vshrn.u16 d10,q5,#8 @; d10 = ((pa <= pb) && (pa <= pc))
+ vshrn.u16 d14,q7,#8 @; d14 = (pb <= pc)
+
+ vand d2,d2,d10 @; d2 = a where 1, 0 where 0
+ vbsl d14,d3,d1 @; d14 = b where 1, c where 0
+ vmvn d10,d10 @; invert d10
+ vand d14,d14,d10 @; d14 = b/c where 1, 0 where 0
+ vadd.i8 d2,d2,d14 @; d2 = p = a/b/c where appropriate
+ vadd.i8 d2,d2,d0 @; d2 = x + p (updated pixel x)
+ vmov d1,d3 @; d1 = b (c for next iteration)
+ vst1.32 {d2[0]},[r2]! @; store 4 bytes (updated pixel x)
+ @; increment curr row pointer
+ vst1.16 {d2[2]},[r2]! @; store 2 bytes (updated pixel x)
+ @; increment curr row pointer
+ bne paeth_filter_6bpp_loop
+
+ b paeth_filter_DONE @; exit loop when
+ @; loop counter == rowbytes
+ #;; -------------------------------
+ #;; PAETH filter, 8 bytes per pixel
+ #;; -------------------------------
+paeth_filter_8bpp:
+ cmp r1, r0
+
+ vld1.8 {d0},[r2] @; load 8 bytes (pixel x) from curr
+ @; row into d0
+ vld1.8 {d1},[r3]! @; load 8 bytes (pixel b) from prev
+ @; row into d1
+ @; increment prev row pointer
+ vadd.i8 d2,d0,d1 @; d2 = x + b = updated pixel x
+ vst1.8 {d2},[r2]! @; store 8 bytes (updated pixel x)
+ @; increment curr row pointer
+ beq paeth_filter_DONE
+
+paeth_filter_8bpp_loop:
+ add r1,r1,r12 @; loop counter += bpp
+ cmp r1,r0
+
+
+ #;; d1[0] = c (b in the previous loop iteration)
+ #;; d2[0] = a (x in the previous loop iteration)
+ vld1.8 {d3},[r3]! @; load 8 bytes (pixel b) from prev
+ @; row into d3
+ vld1.8 {d0},[r2] @; load 8 bytes (pixel x) from curr
+ @; row into d0
+ vshll.u8 q4,d1,#1 @; q4 = c<<1 = 2c
+ vabdl.u8 q3,d2,d1 @; q3 = pb = abs(a - c)
+ vabdl.u8 q2,d3,d1 @; q2 = pa = abs(b - c)
+ vaddl.u8 q5,d2,d3 @; q5 = a + b
+ vabd.u16 q4,q5,q4 @; q4 = pc = abs(a + b - 2c)
+ @
+ vcle.s16 q5,q2,q3 @; q5 = (pa <= pb)
+ vcle.s16 q6,q2,q4 @; q6 = (pa <= pc)
+ vand q5,q5,q6 @; q5 = ((pa <= pb) && (pa <= pc))
+ vcle.s16 q7,q3,q4 @; q7 = (pb <= pc)
+ vshrn.u16 d10,q5,#8 @; d10 = ((pa <= pb) && (pa <= pc))
+ vshrn.u16 d14,q7,#8 @; d14 = (pb <= pc)
+ @
+ vand d2,d2,d10 @; d2 = a where 1, 0 where 0
+ vbsl d14,d3,d1 @; d14 = b where 1, c where 0
+ vmvn d10,d10 @; invert d10
+ vand d14,d14,d10 @; d14 = b/c where 1, 0 where 0
+ vadd.i8 d2,d2,d14 @; d2 = p = a/b/c where appropriate
+ vadd.i8 d2,d2,d0 @; d2 = x + p (updated pixel x)
+ vmov d1,d3 @; d1 = b (c for next iteration)
+ vst1.8 {d2},[r2]! @; store 8 bytes (updated pixel x)
+ @; increment curr row pointer
+ bne paeth_filter_8bpp_loop
+
+ b paeth_filter_DONE @; exit loop when
+ @; loop counter == rowbytes
+paeth_filter_DONE:
+
+ VPOP {q4-q7}
+ bx r14
+
+DONE:
+ bx r14
+
+
+.size png_read_filter_row_neon, .-png_read_filter_row_neon
+ .END
generated by cgit v1.1 at 2024-05-13 22:33:33 +0000