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 29 pld [r0, r1, lsl #0] 30 pld [r2, r3, lsl #0] 31 32 mov r8, #0 ; initialize sum = 0 33 mov r11, #0 ; initialize sse = 0 34 mov r12, #16 ; set loop counter to 16 (=block height) 35 36 loop 37 ; 1st 4 pixels 38 ldr r4, [r0, #0] ; load 4 src pixels 39 ldr r5, [r2, #0] ; load 4 ref pixels 40 41 mov lr, #0 ; constant zero 42 43 usub8 r6, r4, r5 ; calculate difference 44 pld [r0, r1, lsl #1] 45 sel r7, r6, lr ; select bytes with positive difference 46 usub8 r9, r5, r4 ; calculate difference with reversed operands 47 pld [r2, r3, lsl #1] 48 sel r6, r9, lr ; select bytes with negative difference 49 50 ; calculate partial sums 51 usad8 r4, r7, lr ; calculate sum of positive differences 52 usad8 r5, r6, lr ; calculate sum of negative differences 53 orr r6, r6, r7 ; differences of all 4 pixels 54 ; calculate total sum 55 adds r8, r8, r4 ; add positive differences to sum 56 subs r8, r8, r5 ; subtract negative differences from sum 57 58 ; calculate sse 59 uxtb16 r5, r6 ; byte (two pixels) to halfwords 60 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 61 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 62 63 ; 2nd 4 pixels 64 ldr r4, [r0, #4] ; load 4 src pixels 65 ldr r5, [r2, #4] ; load 4 ref pixels 66 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 67 68 usub8 r6, r4, r5 ; calculate difference 69 sel r7, r6, lr ; select bytes with positive difference 70 usub8 r9, r5, r4 ; calculate difference with reversed operands 71 sel r6, r9, lr ; select bytes with negative difference 72 73 ; calculate partial sums 74 usad8 r4, r7, lr ; calculate sum of positive differences 75 usad8 r5, r6, lr ; calculate sum of negative differences 76 orr r6, r6, r7 ; differences of all 4 pixels 77 78 ; calculate total sum 79 add r8, r8, r4 ; add positive differences to sum 80 sub r8, r8, r5 ; subtract negative differences from sum 81 82 ; calculate sse 83 uxtb16 r5, r6 ; byte (two pixels) to halfwords 84 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 85 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 86 87 ; 3rd 4 pixels 88 ldr r4, [r0, #8] ; load 4 src pixels 89 ldr r5, [r2, #8] ; load 4 ref pixels 90 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 91 92 usub8 r6, r4, r5 ; calculate difference 93 sel r7, r6, lr ; select bytes with positive difference 94 usub8 r9, r5, r4 ; calculate difference with reversed operands 95 sel r6, r9, lr ; select bytes with negative difference 96 97 ; calculate partial sums 98 usad8 r4, r7, lr ; calculate sum of positive differences 99 usad8 r5, r6, lr ; calculate sum of negative differences 100 orr r6, r6, r7 ; differences of all 4 pixels 101 102 ; calculate total sum 103 add r8, r8, r4 ; add positive differences to sum 104 sub r8, r8, r5 ; subtract negative differences from sum 105 106 ; calculate sse 107 uxtb16 r5, r6 ; byte (two pixels) to halfwords 108 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 109 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 110 111 ; 4th 4 pixels 112 ldr r4, [r0, #12] ; load 4 src pixels 113 ldr r5, [r2, #12] ; load 4 ref pixels 114 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 115 116 usub8 r6, r4, r5 ; calculate difference 117 add r0, r0, r1 ; set src_ptr to next row 118 sel r7, r6, lr ; select bytes with positive difference 119 usub8 r9, r5, r4 ; calculate difference with reversed operands 120 add r2, r2, r3 ; set dst_ptr to next row 121 sel r6, r9, lr ; select bytes with negative difference 122 123 ; calculate partial sums 124 usad8 r4, r7, lr ; calculate sum of positive differences 125 usad8 r5, r6, lr ; calculate sum of negative differences 126 orr r6, r6, r7 ; differences of all 4 pixels 127 128 ; calculate total sum 129 add r8, r8, r4 ; add positive differences to sum 130 sub r8, r8, r5 ; subtract negative differences from sum 131 132 ; calculate sse 133 uxtb16 r5, r6 ; byte (two pixels) to halfwords 134 uxtb16 r10, r6, ror #8 ; another two pixels to halfwords 135 smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1) 136 smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2) 137 138 139 subs r12, r12, #1 140 141 bne loop 142 143 ; return stuff 144 ldr r6, [sp, #40] ; get address of sse 145 mul r0, r8, r8 ; sum * sum 146 str r11, [r6] ; store sse 147 sub r0, r11, r0, lsr #8 ; return (sse - ((sum * sum) >> 8)) 148 149 ldmfd sp!, {r4-r12, pc} 150 151 ENDP 152 153 END 154 155
