/media/libvpx/vp8/encoder/arm/armv6/vp8_variance8x8_armv6.asm
http://github.com/zpao/v8monkey · Assembly · 101 lines · 55 code · 23 blank · 23 comment · 0 complexity · b4d46b33e1a06a552ff29963590ead42 MD5 · raw file
- ;
- ; Copyright (c) 2011 The WebM project authors. All Rights Reserved.
- ;
- ; Use of this source code is governed by a BSD-style license
- ; that can be found in the LICENSE file in the root of the source
- ; tree. An additional intellectual property rights grant can be found
- ; in the file PATENTS. All contributing project authors may
- ; be found in the AUTHORS file in the root of the source tree.
- ;
- EXPORT |vp8_variance8x8_armv6|
- ARM
- AREA ||.text||, CODE, READONLY, ALIGN=2
- ; r0 unsigned char *src_ptr
- ; r1 int source_stride
- ; r2 unsigned char *ref_ptr
- ; r3 int recon_stride
- ; stack unsigned int *sse
- |vp8_variance8x8_armv6| PROC
- push {r4-r10, lr}
- pld [r0, r1, lsl #0]
- pld [r2, r3, lsl #0]
- mov r12, #8 ; set loop counter to 8 (=block height)
- mov r4, #0 ; initialize sum = 0
- mov r5, #0 ; initialize sse = 0
- loop
- ; 1st 4 pixels
- ldr r6, [r0, #0x0] ; load 4 src pixels
- ldr r7, [r2, #0x0] ; load 4 ref pixels
- mov lr, #0 ; constant zero
- usub8 r8, r6, r7 ; calculate difference
- pld [r0, r1, lsl #1]
- sel r10, r8, lr ; select bytes with positive difference
- usub8 r9, r7, r6 ; calculate difference with reversed operands
- pld [r2, r3, lsl #1]
- sel r8, r9, lr ; select bytes with negative difference
- ; calculate partial sums
- usad8 r6, r10, lr ; calculate sum of positive differences
- usad8 r7, r8, lr ; calculate sum of negative differences
- orr r8, r8, r10 ; differences of all 4 pixels
- ; calculate total sum
- add r4, r4, r6 ; add positive differences to sum
- sub r4, r4, r7 ; substract negative differences from sum
- ; calculate sse
- uxtb16 r7, r8 ; byte (two pixels) to halfwords
- uxtb16 r10, r8, ror #8 ; another two pixels to halfwords
- smlad r5, r7, r7, r5 ; dual signed multiply, add and accumulate (1)
- ; 2nd 4 pixels
- ldr r6, [r0, #0x4] ; load 4 src pixels
- ldr r7, [r2, #0x4] ; load 4 ref pixels
- smlad r5, r10, r10, r5 ; dual signed multiply, add and accumulate (2)
- usub8 r8, r6, r7 ; calculate difference
- add r0, r0, r1 ; set src_ptr to next row
- sel r10, r8, lr ; select bytes with positive difference
- usub8 r9, r7, r6 ; calculate difference with reversed operands
- add r2, r2, r3 ; set dst_ptr to next row
- sel r8, r9, lr ; select bytes with negative difference
- ; calculate partial sums
- usad8 r6, r10, lr ; calculate sum of positive differences
- usad8 r7, r8, lr ; calculate sum of negative differences
- orr r8, r8, r10 ; differences of all 4 pixels
- ; calculate total sum
- add r4, r4, r6 ; add positive differences to sum
- sub r4, r4, r7 ; substract negative differences from sum
- ; calculate sse
- uxtb16 r7, r8 ; byte (two pixels) to halfwords
- uxtb16 r10, r8, ror #8 ; another two pixels to halfwords
- smlad r5, r7, r7, r5 ; dual signed multiply, add and accumulate (1)
- subs r12, r12, #1 ; next row
- smlad r5, r10, r10, r5 ; dual signed multiply, add and accumulate (2)
- bne loop
- ; return stuff
- ldr r8, [sp, #32] ; get address of sse
- mul r1, r4, r4 ; sum * sum
- str r5, [r8] ; store sse
- sub r0, r5, r1, ASR #6 ; return (sse - ((sum * sum) >> 6))
- pop {r4-r10, pc}
- ENDP
- END