Add vp9_tm_predictor_16x16 neon implementation

which is 3.5 times faster than C.

Change-Id: I24439ba7a2971829c11620f34848facf2c916678

vp9/common/arm/neon/vp9_reconintra_neon.asm

@@ -18,6 +18,7 @@
     EXPORT  |vp9_h_predictor_32x32_neon|
     EXPORT  |vp9_tm_predictor_4x4_neon|
     EXPORT  |vp9_tm_predictor_8x8_neon|
+    EXPORT  |vp9_tm_predictor_16x16_neon|
     ARM
     REQUIRE8
     PRESERVE8
@@ -403,4 +404,100 @@ loop_h
     bx                  lr
     ENDP                ; |vp9_tm_predictor_8x8_neon|
 
+;void vp9_tm_predictor_16x16_neon (uint8_t *dst, ptrdiff_t y_stride,
+;                                const uint8_t *above,
+;                                const uint8_t *left)
+; r0  uint8_t *dst
+; r1  ptrdiff_t y_stride
+; r2  const uint8_t *above
+; r3  const uint8_t *left
+
+|vp9_tm_predictor_16x16_neon| PROC
+    ; Load ytop_left = above[-1];
+    sub                 r12, r2, #1
+    ldrb                r12, [r12]
+    vdup.u8             q0, r12
+
+    ; Load above 8 pixels
+    vld1.8              q1, [r2]
+
+    ; preload 8 left into r12
+    vld1.8              d18, [r3]!
+
+    ; Compute above - ytop_left
+    vsubl.u8            q2, d2, d0
+    vsubl.u8            q3, d3, d1
+
+    vmovl.u8            q10, d18
+
+    ; Load left row by row and compute left + (above - ytop_left)
+    ; Process 8 rows in each single loop and loop 2 times to process 16 rows.
+    mov                 r2, #2
+
+loop_16x16_neon
+    ; Process two rows.
+    vdup.16             q0, d20[0]
+    vdup.16             q8, d20[1]
+    vadd.s16            q1, q0, q2
+    vadd.s16            q0, q0, q3
+    vadd.s16            q11, q8, q2
+    vadd.s16            q8, q8, q3
+    vqshrun.s16         d2, q1, #0
+    vqshrun.s16         d3, q0, #0
+    vqshrun.s16         d22, q11, #0
+    vqshrun.s16         d23, q8, #0
+    vdup.16             q0, d20[2]                  ; proload next 2 rows data
+    vdup.16             q8, d20[3]
+    vst1.64             {d2,d3}, [r0], r1
+    vst1.64             {d22,d23}, [r0], r1
+
+    ; Process two rows.
+    vadd.s16            q1, q0, q2
+    vadd.s16            q0, q0, q3
+    vadd.s16            q11, q8, q2
+    vadd.s16            q8, q8, q3
+    vqshrun.s16         d2, q1, #0
+    vqshrun.s16         d3, q0, #0
+    vqshrun.s16         d22, q11, #0
+    vqshrun.s16         d23, q8, #0
+    vdup.16             q0, d21[0]                  ; proload next 2 rows data
+    vdup.16             q8, d21[1]
+    vst1.64             {d2,d3}, [r0], r1
+    vst1.64             {d22,d23}, [r0], r1
+
+    vadd.s16            q1, q0, q2
+    vadd.s16            q0, q0, q3
+    vadd.s16            q11, q8, q2
+    vadd.s16            q8, q8, q3
+    vqshrun.s16         d2, q1, #0
+    vqshrun.s16         d3, q0, #0
+    vqshrun.s16         d22, q11, #0
+    vqshrun.s16         d23, q8, #0
+    vdup.16             q0, d21[2]                  ; proload next 2 rows data
+    vdup.16             q8, d21[3]
+    vst1.64             {d2,d3}, [r0], r1
+    vst1.64             {d22,d23}, [r0], r1
+
+
+    vadd.s16            q1, q0, q2
+    vadd.s16            q0, q0, q3
+    vadd.s16            q11, q8, q2
+    vadd.s16            q8, q8, q3
+    vqshrun.s16         d2, q1, #0
+    vqshrun.s16         d3, q0, #0
+    vqshrun.s16         d22, q11, #0
+    vqshrun.s16         d23, q8, #0
+    vdup.16             q0, d20[2]
+    vdup.16             q8, d20[3]
+    vld1.8              d18, [r3]!                  ; preload 8 left into r12
+    vmovl.u8            q10, d18
+    vst1.64             {d2,d3}, [r0], r1
+    vst1.64             {d22,d23}, [r0], r1
+
+    subs                r2, r2, #1
+    bgt                 loop_16x16_neon
+
+    bx                  lr
+    ENDP                ; |vp9_tm_predictor_16x16_neon|
+
     END

vp9/common/vp9_rtcd_defs.sh

@@ -135,7 +135,7 @@ prototype void vp9_v_predictor_16x16 "uint8_t *dst, ptrdiff_t y_stride, const ui
 specialize vp9_v_predictor_16x16 $sse2_x86inc neon
 
 prototype void vp9_tm_predictor_16x16 "uint8_t *dst, ptrdiff_t y_stride, const uint8_t *above, const uint8_t *left"
-specialize vp9_tm_predictor_16x16 $sse2_x86inc
+specialize vp9_tm_predictor_16x16 $sse2_x86inc neon
 
 prototype void vp9_dc_predictor_16x16 "uint8_t *dst, ptrdiff_t y_stride, const uint8_t *above, const uint8_t *left"
 specialize vp9_dc_predictor_16x16 $sse2_x86inc dspr2