/media/libvpx/vp8/encoder/arm/armv6/vp8_mse16x16_armv6.asm

  1;
  2;  Copyright (c) 2011 The WebM project authors. All Rights Reserved.
  3;
  4;  Use of this source code is governed by a BSD-style license
  5;  that can be found in the LICENSE file in the root of the source
  6;  tree. An additional intellectual property rights grant can be found
  7;  in the file PATENTS.  All contributing project authors may
  8;  be found in the AUTHORS file in the root of the source tree.
  9;
 10
 11
 12    EXPORT  |vp8_mse16x16_armv6|
 13
 14    ARM
 15
 16    AREA ||.text||, CODE, READONLY, ALIGN=2
 17
 18; r0    unsigned char *src_ptr
 19; r1    int source_stride
 20; r2    unsigned char *ref_ptr
 21; r3    int  recon_stride
 22; stack unsigned int *sse
 23;
 24;note: Based on vp8_variance16x16_armv6. In this function, sum is never used.
 25;      So, we can remove this part of calculation.
 26
 27|vp8_mse16x16_armv6| PROC
 28
 29    push    {r4-r9, lr}
 30
 31    pld     [r0, r1, lsl #0]
 32    pld     [r2, r3, lsl #0]
 33
 34    mov     r12, #16            ; set loop counter to 16 (=block height)
 35    mov     r4, #0              ; initialize sse = 0
 36
 37loop
 38    ; 1st 4 pixels
 39    ldr     r5, [r0, #0x0]      ; load 4 src pixels
 40    ldr     r6, [r2, #0x0]      ; load 4 ref pixels
 41
 42    mov     lr, #0              ; constant zero
 43
 44    usub8   r8, r5, r6          ; calculate difference
 45    pld     [r0, r1, lsl #1]
 46    sel     r7, r8, lr          ; select bytes with positive difference
 47    usub8   r9, r6, r5          ; calculate difference with reversed operands
 48    pld     [r2, r3, lsl #1]
 49    sel     r8, r9, lr          ; select bytes with negative difference
 50
 51    ; calculate partial sums
 52    usad8   r5, r7, lr          ; calculate sum of positive differences
 53    usad8   r6, r8, lr          ; calculate sum of negative differences
 54    orr     r8, r8, r7          ; differences of all 4 pixels
 55
 56    ldr     r5, [r0, #0x4]      ; load 4 src pixels
 57
 58    ; calculate sse
 59    uxtb16  r6, r8              ; byte (two pixels) to halfwords
 60    uxtb16  r7, r8, ror #8      ; another two pixels to halfwords
 61    smlad   r4, r6, r6, r4      ; dual signed multiply, add and accumulate (1)
 62
 63    ; 2nd 4 pixels
 64    ldr     r6, [r2, #0x4]      ; load 4 ref pixels
 65    smlad   r4, r7, r7, r4      ; dual signed multiply, add and accumulate (2)
 66
 67    usub8   r8, r5, r6          ; calculate difference
 68    sel     r7, r8, lr          ; select bytes with positive difference
 69    usub8   r9, r6, r5          ; calculate difference with reversed operands
 70    sel     r8, r9, lr          ; select bytes with negative difference
 71
 72    ; calculate partial sums
 73    usad8   r5, r7, lr          ; calculate sum of positive differences
 74    usad8   r6, r8, lr          ; calculate sum of negative differences
 75    orr     r8, r8, r7          ; differences of all 4 pixels
 76    ldr     r5, [r0, #0x8]      ; load 4 src pixels
 77    ; calculate sse
 78    uxtb16  r6, r8              ; byte (two pixels) to halfwords
 79    uxtb16  r7, r8, ror #8      ; another two pixels to halfwords
 80    smlad   r4, r6, r6, r4      ; dual signed multiply, add and accumulate (1)
 81
 82    ; 3rd 4 pixels
 83    ldr     r6, [r2, #0x8]      ; load 4 ref pixels
 84    smlad   r4, r7, r7, r4      ; dual signed multiply, add and accumulate (2)
 85
 86    usub8   r8, r5, r6          ; calculate difference
 87    sel     r7, r8, lr          ; select bytes with positive difference
 88    usub8   r9, r6, r5          ; calculate difference with reversed operands
 89    sel     r8, r9, lr          ; select bytes with negative difference
 90
 91    ; calculate partial sums
 92    usad8   r5, r7, lr          ; calculate sum of positive differences
 93    usad8   r6, r8, lr          ; calculate sum of negative differences
 94    orr     r8, r8, r7          ; differences of all 4 pixels
 95
 96    ldr     r5, [r0, #0xc]      ; load 4 src pixels
 97
 98    ; calculate sse
 99    uxtb16  r6, r8              ; byte (two pixels) to halfwords
100    uxtb16  r7, r8, ror #8      ; another two pixels to halfwords
101    smlad   r4, r6, r6, r4      ; dual signed multiply, add and accumulate (1)
102
103    ; 4th 4 pixels
104    ldr     r6, [r2, #0xc]      ; load 4 ref pixels
105    smlad   r4, r7, r7, r4      ; dual signed multiply, add and accumulate (2)
106
107    usub8   r8, r5, r6          ; calculate difference
108    add     r0, r0, r1          ; set src_ptr to next row
109    sel     r7, r8, lr          ; select bytes with positive difference
110    usub8   r9, r6, r5          ; calculate difference with reversed operands
111    add     r2, r2, r3          ; set dst_ptr to next row
112    sel     r8, r9, lr          ; select bytes with negative difference
113
114    ; calculate partial sums
115    usad8   r5, r7, lr          ; calculate sum of positive differences
116    usad8   r6, r8, lr          ; calculate sum of negative differences
117    orr     r8, r8, r7          ; differences of all 4 pixels
118
119    subs    r12, r12, #1        ; next row
120
121    ; calculate sse
122    uxtb16  r6, r8              ; byte (two pixels) to halfwords
123    uxtb16  r7, r8, ror #8      ; another two pixels to halfwords
124    smlad   r4, r6, r6, r4      ; dual signed multiply, add and accumulate (1)
125    smlad   r4, r7, r7, r4      ; dual signed multiply, add and accumulate (2)
126
127    bne     loop
128
129    ; return stuff
130    ldr     r1, [sp, #28]       ; get address of sse
131    mov     r0, r4              ; return sse
132    str     r4, [r1]            ; store sse
133
134    pop     {r4-r9, pc}
135
136    ENDP
137
138    END