[x265] [PATCH 8/9] AArch64: Add SVE implementation of 16x16 DCT
Jonathan Wright
jonathan.wright at arm.com
Thu Aug 22 15:19:55 UTC 2024
The widening 16-bit multiply + pairwise add pattern in the Neon DCT
paths is a good fit for the SVE 16-bit dot-product instructions. This
patch adds an SVE implementation of the 16x16 DCT path.
Relative performance compared to the Neon implementation:
Neoverse-V1: 1.04x
Neoverse-V2: 1.35x
Neoverse-N2: 1.42x
---
source/common/aarch64/dct-prim-sve.cpp | 122 +++++++++++++++++++++++++
source/common/aarch64/dct-prim.cpp | 16 ----
source/common/aarch64/dct-prim.h | 28 ++++++
3 files changed, 150 insertions(+), 16 deletions(-)
diff --git a/source/common/aarch64/dct-prim-sve.cpp b/source/common/aarch64/dct-prim-sve.cpp
index 2f32e6397..f5a49b457 100644
--- a/source/common/aarch64/dct-prim-sve.cpp
+++ b/source/common/aarch64/dct-prim-sve.cpp
@@ -145,6 +145,110 @@ static void partialButterfly8_sve(const int16_t *src, int16_t *dst)
}
}
+template<int shift>
+static void partialButterfly16_sve(const int16_t *src, int16_t *dst)
+{
+ const int line = 16;
+
+ int16x8_t O[line];
+ int16x8_t EO[line / 2];
+ int32x4_t EEE[line];
+ int32x4_t EEO[line];
+
+ for (int i = 0; i < line; i += 2)
+ {
+ int16x8_t s0_lo = vld1q_s16(src + i * line);
+ int16x8_t s0_hi = rev16(vld1q_s16(src + i * line + 8));
+
+ int16x8_t s1_lo = vld1q_s16(src + (i + 1) * line);
+ int16x8_t s1_hi = rev16(vld1q_s16(src + (i + 1) * line + 8));
+
+ int32x4_t E0[2];
+ E0[0] = vaddl_s16(vget_low_s16(s0_lo), vget_low_s16(s0_hi));
+ E0[1] = vaddl_s16(vget_high_s16(s0_lo), vget_high_s16(s0_hi));
+
+ int32x4_t E1[2];
+ E1[0] = vaddl_s16(vget_low_s16(s1_lo), vget_low_s16(s1_hi));
+ E1[1] = vaddl_s16(vget_high_s16(s1_lo), vget_high_s16(s1_hi));
+
+ O[i + 0] = vsubq_s16(s0_lo, s0_hi);
+ O[i + 1] = vsubq_s16(s1_lo, s1_hi);
+
+ int16x4_t EO_lo = vmovn_s32(vsubq_s32(E0[0], rev32(E0[1])));
+ int16x4_t EO_hi = vmovn_s32(vsubq_s32(E1[0], rev32(E1[1])));
+ EO[i / 2] = vcombine_s16(EO_lo, EO_hi);
+
+ int32x4_t EE0 = vaddq_s32(E0[0], rev32(E0[1]));
+ int32x4_t EE1 = vaddq_s32(E1[0], rev32(E1[1]));
+
+ int32x4_t t0 = vreinterpretq_s32_s64(
+ vzip1q_s64(vreinterpretq_s64_s32(EE0), vreinterpretq_s64_s32(EE1)));
+ int32x4_t t1 = vrev64q_s32(vreinterpretq_s32_s64(
+ vzip2q_s64(vreinterpretq_s64_s32(EE0),
+ vreinterpretq_s64_s32(EE1))));
+
+ EEE[i / 2] = vaddq_s32(t0, t1);
+ EEO[i / 2] = vsubq_s32(t0, t1);
+ }
+
+ for (int i = 0; i < line; i += 4)
+ {
+ for (int k = 1; k < 16; k += 2)
+ {
+ int16x8_t c0_c4 = vld1q_s16(&g_t16[k][0]);
+
+ int64x2_t t0 = x265_sdotq_s16(vdupq_n_s64(0), c0_c4, O[i + 0]);
+ int64x2_t t1 = x265_sdotq_s16(vdupq_n_s64(0), c0_c4, O[i + 1]);
+ int64x2_t t2 = x265_sdotq_s16(vdupq_n_s64(0), c0_c4, O[i + 2]);
+ int64x2_t t3 = x265_sdotq_s16(vdupq_n_s64(0), c0_c4, O[i + 3]);
+
+ int32x4_t t01 = vcombine_s32(vmovn_s64(t0), vmovn_s64(t1));
+ int32x4_t t23 = vcombine_s32(vmovn_s64(t2), vmovn_s64(t3));
+ int16x4_t res = vrshrn_n_s32(vpaddq_s32(t01, t23), shift);
+ vst1_s16(dst + k * line, res);
+ }
+
+ for (int k = 2; k < 16; k += 4)
+ {
+ int16x8_t c0 = vld1q_s16(t8_odd[(k - 2) / 4]);
+
+ int64x2_t t0 = x265_sdotq_s16(vdupq_n_s64(0), c0, EO[i / 2 + 0]);
+ int64x2_t t1 = x265_sdotq_s16(vdupq_n_s64(0), c0, EO[i / 2 + 1]);
+
+ int32x4_t t01 = vcombine_s32(vmovn_s64(t0), vmovn_s64(t1));
+ int16x4_t res = vrshrn_n_s32(t01, shift);
+ vst1_s16(dst + k * line, res);
+ }
+
+ int32x4_t c0 = vld1q_s32(t8_even[0]);
+ int32x4_t c4 = vld1q_s32(t8_even[1]);
+ int32x4_t c8 = vld1q_s32(t8_even[2]);
+ int32x4_t c12 = vld1q_s32(t8_even[3]);
+
+ int32x4_t t0 = vpaddq_s32(EEE[i / 2 + 0], EEE[i / 2 + 1]);
+ int32x4_t t1 = vmulq_s32(c0, t0);
+ int16x4_t res0 = vrshrn_n_s32(t1, shift);
+ vst1_s16(dst + 0 * line, res0);
+
+ int32x4_t t2 = vmulq_s32(c4, EEO[i / 2 + 0]);
+ int32x4_t t3 = vmulq_s32(c4, EEO[i / 2 + 1]);
+ int16x4_t res4 = vrshrn_n_s32(vpaddq_s32(t2, t3), shift);
+ vst1_s16(dst + 4 * line, res4);
+
+ int32x4_t t4 = vmulq_s32(c8, EEE[i / 2 + 0]);
+ int32x4_t t5 = vmulq_s32(c8, EEE[i / 2 + 1]);
+ int16x4_t res8 = vrshrn_n_s32(vpaddq_s32(t4, t5), shift);
+ vst1_s16(dst + 8 * line, res8);
+
+ int32x4_t t6 = vmulq_s32(c12, EEO[i / 2 + 0]);
+ int32x4_t t7 = vmulq_s32(c12, EEO[i / 2 + 1]);
+ int16x4_t res12 = vrshrn_n_s32(vpaddq_s32(t6, t7), shift);
+ vst1_s16(dst + 12 * line, res12);
+
+ dst += 4;
+ }
+}
+
}
@@ -168,9 +272,27 @@ void dct8_sve(const int16_t *src, int16_t *dst, intptr_t srcStride)
partialButterfly8_sve<shift_pass2>(coef, dst);
}
+void dct16_sve(const int16_t *src, int16_t *dst, intptr_t srcStride)
+{
+ const int shift_pass1 = 3 + X265_DEPTH - 8;
+ const int shift_pass2 = 10;
+
+ ALIGN_VAR_32(int16_t, coef[16 * 16]);
+ ALIGN_VAR_32(int16_t, block[16 * 16]);
+
+ for (int i = 0; i < 16; i++)
+ {
+ memcpy(&block[i * 16], &src[i * srcStride], 16 * sizeof(int16_t));
+ }
+
+ partialButterfly16_sve<shift_pass1>(block, coef);
+ partialButterfly16_sve<shift_pass2>(coef, dst);
+}
+
void setupDCTPrimitives_sve(EncoderPrimitives &p)
{
p.cu[BLOCK_8x8].dct = dct8_sve;
+ p.cu[BLOCK_16x16].dct = dct16_sve;
}
};
diff --git a/source/common/aarch64/dct-prim.cpp b/source/common/aarch64/dct-prim.cpp
index 09ba9b973..e75783425 100644
--- a/source/common/aarch64/dct-prim.cpp
+++ b/source/common/aarch64/dct-prim.cpp
@@ -28,22 +28,6 @@ const int32_t t8_even[4][4] =
{ 36, -83, 36, -83 },
};
-static int16x8_t rev16(const int16x8_t a)
-{
- static const uint8x16_t tbl = {14, 15, 12, 13, 10, 11, 8, 9, 6, 7, 4, 5, 2, 3, 0, 1};
- const int8x16_t a_s8 = vreinterpretq_s8_s16(a);
-
- return vreinterpretq_s16_s8(vqtbx1q_s8(a_s8, a_s8, tbl));
-}
-
-static int32x4_t rev32(const int32x4_t a)
-{
- static const uint8x16_t tbl = {12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3};
- const int8x16_t a_s8 = vreinterpretq_s8_s32(a);
-
- return vreinterpretq_s32_s8(vqtbx1q_s8(a_s8, a_s8, tbl));
-}
-
static void transpose_4x4x16(int16x4_t &x0, int16x4_t &x1, int16x4_t &x2, int16x4_t &x3)
{
int32x2_t s0, s1, s2, s3;
diff --git a/source/common/aarch64/dct-prim.h b/source/common/aarch64/dct-prim.h
index d62a90075..8ddfd3856 100644
--- a/source/common/aarch64/dct-prim.h
+++ b/source/common/aarch64/dct-prim.h
@@ -6,9 +6,37 @@
#include "primitives.h"
#include "contexts.h" // costCoeffNxN_c
#include "threading.h" // CLZ
+#include <arm_neon.h>
namespace X265_NS
{
+
+const uint8_t rev16_tbl[16] =
+{
+ 14, 15, 12, 13, 10, 11, 8, 9, 6, 7, 4, 5, 2, 3, 0, 1
+};
+
+const uint8_t rev32_tbl[16] =
+{
+ 12, 13, 14, 15, 8, 9, 10, 11, 4, 5, 6, 7, 0, 1, 2, 3
+};
+
+static inline int16x8_t rev16(const int16x8_t a)
+{
+ const uint8x16_t tbl = vld1q_u8(rev16_tbl);
+ const int8x16_t a_s8 = vreinterpretq_s8_s16(a);
+
+ return vreinterpretq_s16_s8(vqtbx1q_s8(a_s8, a_s8, tbl));
+}
+
+static inline int32x4_t rev32(const int32x4_t a)
+{
+ const uint8x16_t tbl = vld1q_u8(rev32_tbl);
+ const int8x16_t a_s8 = vreinterpretq_s8_s32(a);
+
+ return vreinterpretq_s32_s8(vqtbx1q_s8(a_s8, a_s8, tbl));
+}
+
// x265 private namespace
void setupDCTPrimitives_neon(EncoderPrimitives &p);
#if defined(HAVE_SVE) && HAVE_SVE_BRIDGE
--
2.42.1
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