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_variance16x16_armv6| 13 14 ARM 15 REQUIRE8 16 PRESERVE8 17 18 AREA ||.text||, CODE, READONLY, ALIGN=2 19 20 ; r0 unsigned char *src_ptr 21 ; r1 int source_stride 22 ; r2 unsigned char *ref_ptr 23 ; r3 int recon_stride 24 ; stack unsigned int *sse 25 |vp8_variance16x16_armv6| PROC 26 27 stmfd sp!, {r4-r12, lr} 28 mov r8, #0 ; initialize sum = 0 29 mov r11, #0 ; initialize sse = 0 30 mov r12, #16 ; set loop counter to 16 (=block height) 31 32 loop 33 ; 1st 4 pixels 34 ldr r4, [r0, #0] ; load 4 src pixels 35 ldr r5, [r2, #0] ; load 4 ref pixels 36 37 mov lr, #0 ; constant zero 38 39 usub8 r6, r4, r5 ; calculate difference 40 sel r7, r6, lr ; select bytes with positive difference 41 usub8 r9, r5, r4 ; calculate difference with reversed operands 42 sel r6, r9, lr ; select bytes with negative difference 43 44 ; calculate partial sums 45 usad8 r4, r7, lr ; calculate sum of positive differences 46 usad8 r5, r6, lr ; calculate sum of negative differences 47 orr r6, r6, r7 ; differences of all 4 pixels 48 ; calculate total sum 49 adds r8, r8, r4 ; add positive differences to sum 50 subs r8, r8, r5 ; substract negative differences from sum 51 52 ; calculate sse 53 uxtb16 r5, r6 ; byte (two pixels) to halfwords 54 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 55 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 56 57 ; 2nd 4 pixels 58 ldr r4, [r0, #4] ; load 4 src pixels 59 ldr r5, [r2, #4] ; load 4 ref pixels 60 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 61 62 usub8 r6, r4, r5 ; calculate difference 63 sel r7, r6, lr ; select bytes with positive difference 64 usub8 r9, r5, r4 ; calculate difference with reversed operands 65 sel r6, r9, lr ; select bytes with negative difference 66 67 ; calculate partial sums 68 usad8 r4, r7, lr ; calculate sum of positive differences 69 usad8 r5, r6, lr ; calculate sum of negative differences 70 orr r6, r6, r7 ; differences of all 4 pixels 71 72 ; calculate total sum 73 add r8, r8, r4 ; add positive differences to sum 74 sub r8, r8, r5 ; substract negative differences from sum 75 76 ; calculate sse 77 uxtb16 r5, r6 ; byte (two pixels) to halfwords 78 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 79 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 80 81 ; 3rd 4 pixels 82 ldr r4, [r0, #8] ; load 4 src pixels 83 ldr r5, [r2, #8] ; load 4 ref pixels 84 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 85 86 usub8 r6, r4, r5 ; calculate difference 87 sel r7, r6, lr ; select bytes with positive difference 88 usub8 r9, r5, r4 ; calculate difference with reversed operands 89 sel r6, r9, lr ; select bytes with negative difference 90 91 ; calculate partial sums 92 usad8 r4, r7, lr ; calculate sum of positive differences 93 usad8 r5, r6, lr ; calculate sum of negative differences 94 orr r6, r6, r7 ; differences of all 4 pixels 95 96 ; calculate total sum 97 add r8, r8, r4 ; add positive differences to sum 98 sub r8, r8, r5 ; substract negative differences from sum 99 100 ; calculate sse 101 uxtb16 r5, r6 ; byte (two pixels) to halfwords 102 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 103 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 104 105 ; 4th 4 pixels 106 ldr r4, [r0, #12] ; load 4 src pixels 107 ldr r5, [r2, #12] ; load 4 ref pixels 108 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 109 110 usub8 r6, r4, r5 ; calculate difference 111 add r0, r0, r1 ; set src_ptr to next row 112 sel r7, r6, lr ; select bytes with positive difference 113 usub8 r9, r5, r4 ; calculate difference with reversed operands 114 add r2, r2, r3 ; set dst_ptr to next row 115 sel r6, r9, lr ; select bytes with negative difference 116 117 ; calculate partial sums 118 usad8 r4, r7, lr ; calculate sum of positive differences 119 usad8 r5, r6, lr ; calculate sum of negative differences 120 orr r6, r6, r7 ; differences of all 4 pixels 121 122 ; calculate total sum 123 add r8, r8, r4 ; add positive differences to sum 124 sub r8, r8, r5 ; substract negative differences from sum 125 126 ; calculate sse 127 uxtb16 r5, r6 ; byte (two pixels) to halfwords 128 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 129 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 130 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 131 132 133 subs r12, r12, #1 134 135 bne loop 136 137 ; return stuff 138 ldr r6, [sp, #40] ; get address of sse 139 mul r0, r8, r8 ; sum * sum 140 str r11, [r6] ; store sse 141 sub r0, r11, r0, asr #8 ; return (sse - ((sum * sum) >> 8)) 142 143 ldmfd sp!, {r4-r12, pc} 144 145 ENDP 146 147 END 148 149
