--- /dev/null
+;
+; 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_variance16x16_armv6|
+
+ ARM
+ REQUIRE8
+ PRESERVE8
+
+ 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_variance16x16_armv6| PROC
+
+ stmfd sp!, {r4-r12, lr}
+ mov r12, #16 ; set loop counter to 16 (=block height)
+ mov r8, #0 ; initialize sum = 0
+ mov r11, #0 ; initialize sse = 0
+
+loop
+ ; 1st 4 pixels
+ ldr r4, [r0, #0x0] ; load 4 src pixels
+ ldr r5, [r2, #0x0] ; load 4 ref pixels
+
+ mov lr, #0 ; constant zero
+
+ usub8 r6, r4, r5 ; calculate difference
+ sel r7, r6, lr ; select bytes with positive difference
+ usub8 r9, r5, r4 ; calculate difference with reversed operands
+ sel r6, r9, lr ; select bytes with negative difference
+
+ ; calculate partial sums
+ usad8 r4, r7, lr ; calculate sum of positive differences
+ usad8 r5, r6, lr ; calculate sum of negative differences
+ orr r6, r6, r7 ; differences of all 4 pixels
+ ; calculate total sum
+ adds r8, r8, r4 ; add positive differences to sum
+ subs r8, r8, r5 ; substract negative differences from sum
+
+ ; calculate sse
+ uxtb16 r5, r6 ; byte (two pixels) to halfwords
+ uxtb16 r10, r6, ror #8 ; another two pixels to halfwords
+ smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1)
+
+ ; 2nd 4 pixels
+ ldr r4, [r0, #0x4] ; load 4 src pixels
+ ldr r5, [r2, #0x4] ; load 4 ref pixels
+ smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2)
+
+ usub8 r6, r4, r5 ; calculate difference
+ sel r7, r6, lr ; select bytes with positive difference
+ usub8 r9, r5, r4 ; calculate difference with reversed operands
+ sel r6, r9, lr ; select bytes with negative difference
+
+ ; calculate partial sums
+ usad8 r4, r7, lr ; calculate sum of positive differences
+ usad8 r5, r6, lr ; calculate sum of negative differences
+ orr r6, r6, r7 ; differences of all 4 pixels
+
+ ; calculate total sum
+ add r8, r8, r4 ; add positive differences to sum
+ sub r8, r8, r5 ; substract negative differences from sum
+
+ ; calculate sse
+ uxtb16 r5, r6 ; byte (two pixels) to halfwords
+ uxtb16 r10, r6, ror #8 ; another two pixels to halfwords
+ smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1)
+
+ ; 3rd 4 pixels
+ ldr r4, [r0, #0x8] ; load 4 src pixels
+ ldr r5, [r2, #0x8] ; load 4 ref pixels
+ smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2)
+
+ usub8 r6, r4, r5 ; calculate difference
+ sel r7, r6, lr ; select bytes with positive difference
+ usub8 r9, r5, r4 ; calculate difference with reversed operands
+ sel r6, r9, lr ; select bytes with negative difference
+
+ ; calculate partial sums
+ usad8 r4, r7, lr ; calculate sum of positive differences
+ usad8 r5, r6, lr ; calculate sum of negative differences
+ orr r6, r6, r7 ; differences of all 4 pixels
+
+ ; calculate total sum
+ add r8, r8, r4 ; add positive differences to sum
+ sub r8, r8, r5 ; substract negative differences from sum
+
+ ; calculate sse
+ uxtb16 r5, r6 ; byte (two pixels) to halfwords
+ uxtb16 r10, r6, ror #8 ; another two pixels to halfwords
+ smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1)
+
+ ; 4th 4 pixels
+ ldr r4, [r0, #0xc] ; load 4 src pixels
+ ldr r5, [r2, #0xc] ; load 4 ref pixels
+ smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2)
+
+ usub8 r6, r4, r5 ; calculate difference
+ add r0, r0, r1 ; set src_ptr to next row
+ sel r7, r6, lr ; select bytes with positive difference
+ usub8 r9, r5, r4 ; calculate difference with reversed operands
+ add r2, r2, r3 ; set dst_ptr to next row
+ sel r6, r9, lr ; select bytes with negative difference
+
+ ; calculate partial sums
+ usad8 r4, r7, lr ; calculate sum of positive differences
+ usad8 r5, r6, lr ; calculate sum of negative differences
+ orr r6, r6, r7 ; differences of all 4 pixels
+
+ ; calculate total sum
+ add r8, r8, r4 ; add positive differences to sum
+ sub r8, r8, r5 ; substract negative differences from sum
+
+ ; calculate sse
+ uxtb16 r5, r6 ; byte (two pixels) to halfwords
+ uxtb16 r10, r6, ror #8 ; another two pixels to halfwords
+ smlad r11, r5, r5, r11 ; dual signed multiply, add and accumulate (1)
+ smlad r11, r10, r10, r11 ; dual signed multiply, add and accumulate (2)
+
+
+ subs r12, r12, #1
+
+ bne loop
+
+ ; return stuff
+ ldr r6, [sp, #0x28] ; get address of sse
+ mul r0, r8, r8 ; sum * sum
+ str r11, [r6] ; store sse
+ sub r0, r11, r0, ASR #8 ; return (sse - ((sum * sum) >> 8))
+
+ ldmfd sp!, {r4-r12, pc}
+
+ ENDP
+
+ END
projects / libvpx / commitdiff