Add 4-tap specialisation to aom_convolve8_horiz_neon
Add specialised path for 4-tap filters in aom_convolve8_horiz_neon. This
gives between 40% and 50% uplift compared to using the 8-tap path.
Change-Id: If48815ef9d1d8fe6882f3a1290d8a7cbffc57e9e
diff --git a/aom_dsp/arm/aom_convolve8_neon.c b/aom_dsp/arm/aom_convolve8_neon.c
index 142aaf8..6a177b2 100644
--- a/aom_dsp/arm/aom_convolve8_neon.c
+++ b/aom_dsp/arm/aom_convolve8_neon.c
@@ -20,6 +20,7 @@
#include "aom/aom_integer.h"
#include "aom_dsp/aom_dsp_common.h"
#include "aom_dsp/aom_filter.h"
+#include "aom_dsp/arm/aom_filter.h"
#include "aom_dsp/arm/mem_neon.h"
#include "aom_dsp/arm/transpose_neon.h"
#include "aom_ports/mem.h"
@@ -64,20 +65,11 @@
return vqrshrun_n_s16(sum, FILTER_BITS);
}
-void aom_convolve8_horiz_neon(const uint8_t *src, ptrdiff_t src_stride,
- uint8_t *dst, ptrdiff_t dst_stride,
- const int16_t *filter_x, int x_step_q4,
- const int16_t *filter_y, int y_step_q4, int w,
- int h) {
- assert((intptr_t)dst % 4 == 0);
- assert(dst_stride % 4 == 0);
-
- (void)x_step_q4;
- (void)filter_y;
- (void)y_step_q4;
-
- src -= ((SUBPEL_TAPS / 2) - 1);
-
+static INLINE void convolve8_horiz_8tap_neon(const uint8_t *src,
+ ptrdiff_t src_stride, uint8_t *dst,
+ ptrdiff_t dst_stride,
+ const int16_t *filter_x, int w,
+ int h) {
const int16x8_t filter = vld1q_s16(filter_x);
if (h == 4) {
@@ -239,6 +231,137 @@
}
}
+static INLINE int16x4_t convolve4_4(const int16x4_t s0, const int16x4_t s1,
+ const int16x4_t s2, const int16x4_t s3,
+ const int16x4_t filter) {
+ int16x4_t sum = vmul_lane_s16(s0, filter, 0);
+ sum = vmla_lane_s16(sum, s1, filter, 1);
+ sum = vmla_lane_s16(sum, s2, filter, 2);
+ sum = vmla_lane_s16(sum, s3, filter, 3);
+
+ return sum;
+}
+
+static INLINE uint8x8_t convolve4_8(const int16x8_t s0, const int16x8_t s1,
+ const int16x8_t s2, const int16x8_t s3,
+ const int16x4_t filter) {
+ int16x8_t sum = vmulq_lane_s16(s0, filter, 0);
+ sum = vmlaq_lane_s16(sum, s1, filter, 1);
+ sum = vmlaq_lane_s16(sum, s2, filter, 2);
+ sum = vmlaq_lane_s16(sum, s3, filter, 3);
+
+ // We halved the filter values so -1 from right shift.
+ return vqrshrun_n_s16(sum, FILTER_BITS - 1);
+}
+
+static INLINE void convolve8_horiz_4tap_neon(const uint8_t *src,
+ ptrdiff_t src_stride, uint8_t *dst,
+ ptrdiff_t dst_stride,
+ const int16_t *filter_x, int w,
+ int h) {
+ // All filter values are even, halve to reduce intermediate precision
+ // requirements.
+ const int16x4_t filter = vshr_n_s16(vld1_s16(filter_x + 2), 1);
+
+ if (w == 4) {
+ do {
+ int16x8_t t0 =
+ vreinterpretq_s16_u16(vmovl_u8(vld1_u8(src + 0 * src_stride)));
+ int16x8_t t1 =
+ vreinterpretq_s16_u16(vmovl_u8(vld1_u8(src + 1 * src_stride)));
+
+ int16x4_t s0[4], s1[4];
+ s0[0] = vget_low_s16(t0);
+ s0[1] = vget_low_s16(vextq_s16(t0, t0, 1));
+ s0[2] = vget_low_s16(vextq_s16(t0, t0, 2));
+ s0[3] = vget_low_s16(vextq_s16(t0, t0, 3));
+
+ s1[0] = vget_low_s16(t1);
+ s1[1] = vget_low_s16(vextq_s16(t1, t1, 1));
+ s1[2] = vget_low_s16(vextq_s16(t1, t1, 2));
+ s1[3] = vget_low_s16(vextq_s16(t1, t1, 3));
+
+ int16x4_t d0 = convolve4_4(s0[0], s0[1], s0[2], s0[3], filter);
+ int16x4_t d1 = convolve4_4(s1[0], s1[1], s1[2], s1[3], filter);
+ // We halved the filter values so -1 from right shift.
+ uint8x8_t d01 = vqrshrun_n_s16(vcombine_s16(d0, d1), FILTER_BITS - 1);
+
+ store_u8x4_strided_x2(dst + 0 * dst_stride, dst_stride, d01);
+
+ src += 2 * src_stride;
+ dst += 2 * dst_stride;
+ h -= 2;
+ } while (h > 0);
+ } else {
+ do {
+ int width = w;
+ const uint8_t *s = src;
+ uint8_t *d = dst;
+
+ int16x8_t t0 =
+ vreinterpretq_s16_u16(vmovl_u8(vld1_u8(s + 0 * src_stride)));
+ int16x8_t t1 =
+ vreinterpretq_s16_u16(vmovl_u8(vld1_u8(s + 1 * src_stride)));
+
+ s += 8;
+ do {
+ int16x8_t t2 =
+ vreinterpretq_s16_u16(vmovl_u8(vld1_u8(s + 0 * src_stride)));
+ int16x8_t t3 =
+ vreinterpretq_s16_u16(vmovl_u8(vld1_u8(s + 1 * src_stride)));
+
+ int16x8_t s0[4], s1[4];
+ s0[0] = t0;
+ s0[1] = vextq_s16(t0, t2, 1);
+ s0[2] = vextq_s16(t0, t2, 2);
+ s0[3] = vextq_s16(t0, t2, 3);
+
+ s1[0] = t1;
+ s1[1] = vextq_s16(t1, t3, 1);
+ s1[2] = vextq_s16(t1, t3, 2);
+ s1[3] = vextq_s16(t1, t3, 3);
+
+ uint8x8_t d0 = convolve4_8(s0[0], s0[1], s0[2], s0[3], filter);
+ uint8x8_t d1 = convolve4_8(s1[0], s1[1], s1[2], s1[3], filter);
+
+ store_u8_8x2(d, dst_stride, d0, d1);
+
+ t0 = t2;
+ t1 = t3;
+
+ s += 8;
+ d += 8;
+ width -= 8;
+ } while (width != 0);
+ src += 2 * src_stride;
+ dst += 2 * dst_stride;
+ h -= 2;
+ } while (h > 0);
+ }
+}
+
+void aom_convolve8_horiz_neon(const uint8_t *src, ptrdiff_t src_stride,
+ uint8_t *dst, ptrdiff_t dst_stride,
+ const int16_t *filter_x, int x_step_q4,
+ const int16_t *filter_y, int y_step_q4, int w,
+ int h) {
+ assert((intptr_t)dst % 4 == 0);
+ assert(dst_stride % 4 == 0);
+
+ (void)x_step_q4;
+ (void)filter_y;
+ (void)y_step_q4;
+
+ src -= ((SUBPEL_TAPS / 2) - 1);
+
+ if (get_filter_taps_convolve8(filter_x) <= 4) {
+ convolve8_horiz_4tap_neon(src + 2, src_stride, dst, dst_stride, filter_x, w,
+ h);
+ } else {
+ convolve8_horiz_8tap_neon(src, src_stride, dst, dst_stride, filter_x, w, h);
+ }
+}
+
void aom_convolve8_vert_neon(const uint8_t *src, ptrdiff_t src_stride,
uint8_t *dst, ptrdiff_t dst_stride,
const int16_t *filter_x, int x_step_q4,
