COMPMID-464 Implement Depthwise convolution 3x3 on NEON

Change-Id: Ie4e1803a52afac6b6c597c6e551729dad2347cd1
Reviewed-on: http://mpd-gerrit.cambridge.arm.com/92607
Tested-by: Kaizen <jeremy.johnson+kaizengerrit@arm.com>
Reviewed-by: Pablo Tello <pablo.tello@arm.com>

1 files changed, 488 insertions, 0 deletions

diff --git a/arm_compute/core/NEON/kernels/convolution/NEDirectConvolutionDetail.h b/arm_compute/core/NEON/kernels/convolution/NEDirectConvolutionDetail.h
new file mode 100644
index 0000000000..aac70b0a81
--- /dev/null
+++ b/arm_compute/core/NEON/kernels/convolution/NEDirectConvolutionDetail.h
@@ -0,0 +1,488 @@
+/*
+ * Copyright (c) 2017 ARM Limited.
+ *
+ * SPDX-License-Identifier: MIT
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to
+ * deal in the Software without restriction, including without limitation the
+ * rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+ * sell copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in all
+ * copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ */
+
+#ifndef __ARM_COMPUTE_NEDIRECTCONVOLUTIONDETAIL_H__
+#define __ARM_COMPUTE_NEDIRECTCONVOLUTIONDETAIL_H__
+
+#include "arm_compute/core/AccessWindowStatic.h"
+#include "arm_compute/core/NEON/NEFixedPoint.h"
+
+#include <arm_neon.h>
+
+namespace arm_compute
+{
+namespace detail
+{
+/** Loads a 3x3 matrix as a row  (float).
+ *
+ * @param[in] ptr Pointer to a float 3x3 matrix.
+ *
+ * @return The loaded matrix.
+ */
+inline float32x4x3_t load_matrix_row(const float *ptr)
+{
+    const float32x4x3_t r =
+    {
+        {
+            vld1q_dup_f32(ptr),
+            vld1q_dup_f32(1 + ptr),
+            vld1q_dup_f32(2 + ptr)
+        }
+    };
+    return r;
+}
+
+/** Loads a 3x3 matrix as a row  (qint8_t).
+ *
+ * @param[in] ptr Pointer to a qint8 3x3 matrix.
+ *
+ * @return The loaded matrix.
+ */
+inline qint8x8x3_t load_matrix_row(const qint8_t *ptr)
+{
+    /* ptr is a pointer to a row in a 3x3 matrix, the function returns 3 vectors holding exactly the same value in all lanes:
+       r.val[0] contains the first element, r.val[1] the second element and r.val[2] the third element (in all lanes) */
+    const qint8x8x3_t r =
+    {
+        {
+            vld1_dup_qs8(ptr),
+            vld1_dup_qs8(1 + ptr),
+            vld1_dup_qs8(2 + ptr)
+        }
+    };
+    return r;
+}
+
+/** Perform a convolve3x3 on float32.
+ *
+ * @param[in] in_top               Pointer to the first row of the input.
+ * @param[in] in_mid               Pointer to the second row of the input.
+ * @param[in] in_low               Pointer to the third row of the input.
+ * @param[in] m0                   First row of the filter.
+ * @param[in] m1                   Second row of the filter.
+ * @param[in] m2                   Third row of the filter.
+ * @param[in] fixed_point_position (Optional) Fixed point position.
+ *
+ */
+template <unsigned int stridex>
+float32x4x2_t convolve_3x3(const float *in_top, const float *in_mid, const float *in_low, const float32x4x3_t &m0, const float32x4x3_t &m1, const float32x4x3_t &m2, int fixed_point_position);
+
+template <>
+inline float32x4x2_t convolve_3x3<1>(const float *in_top, const float *in_mid, const float *in_low, const float32x4x3_t &m0, const float32x4x3_t &m1, const float32x4x3_t &m2, int fixed_point_position)
+{
+    ARM_COMPUTE_UNUSED(fixed_point_position);
+
+    const float32x4x3_t vtop =
+    {
+        {
+            vld1q_f32(in_top),
+            vld1q_f32(in_top + 4),
+            vld1q_f32(in_top + 8)
+        }
+    };
+    const float32x4x3_t vmid =
+    {
+        {
+            vld1q_f32(in_mid),
+            vld1q_f32(in_mid + 4),
+            vld1q_f32(in_mid + 8)
+        }
+    };
+    const float32x4x3_t vlow =
+    {
+        {
+            vld1q_f32(in_low),
+            vld1q_f32(in_low + 4),
+            vld1q_f32(in_low + 8)
+        }
+    };
+    float32x4x2_t out =
+    {
+        {
+            vmulq_f32(vtop.val[0], m0.val[0]),
+            vmulq_f32(vtop.val[1], m0.val[0])
+        }
+    };
+    out.val[0] = vmlaq_f32(out.val[0], vextq_f32(vtop.val[0], vtop.val[1], 1), m0.val[1]);
+    out.val[0] = vmlaq_f32(out.val[0], vextq_f32(vtop.val[0], vtop.val[1], 2), m0.val[2]);
+
+    out.val[0] = vmlaq_f32(out.val[0], vmid.val[0], m1.val[0]);
+    out.val[0] = vmlaq_f32(out.val[0], vextq_f32(vmid.val[0], vmid.val[1], 1), m1.val[1]);
+    out.val[0] = vmlaq_f32(out.val[0], vextq_f32(vmid.val[0], vmid.val[1], 2), m1.val[2]);
+
+    out.val[0] = vmlaq_f32(out.val[0], vlow.val[0], m2.val[0]);
+    out.val[0] = vmlaq_f32(out.val[0], vextq_f32(vlow.val[0], vlow.val[1], 1), m2.val[1]);
+    out.val[0] = vmlaq_f32(out.val[0], vextq_f32(vlow.val[0], vlow.val[1], 2), m2.val[2]);
+
+    out.val[1] = vmlaq_f32(out.val[1], vextq_f32(vtop.val[1], vtop.val[2], 1), m0.val[1]);
+    out.val[1] = vmlaq_f32(out.val[1], vextq_f32(vtop.val[1], vtop.val[2], 2), m0.val[2]);
+
+    out.val[1] = vmlaq_f32(out.val[1], vmid.val[1], m1.val[0]);
+    out.val[1] = vmlaq_f32(out.val[1], vextq_f32(vmid.val[1], vmid.val[2], 1), m1.val[1]);
+    out.val[1] = vmlaq_f32(out.val[1], vextq_f32(vmid.val[1], vmid.val[2], 2), m1.val[2]);
+
+    out.val[1] = vmlaq_f32(out.val[1], vlow.val[1], m2.val[0]);
+    out.val[1] = vmlaq_f32(out.val[1], vextq_f32(vlow.val[1], vlow.val[2], 1), m2.val[1]);
+    out.val[1] = vmlaq_f32(out.val[1], vextq_f32(vlow.val[1], vlow.val[2], 2), m2.val[2]);
+    return out;
+}
+
+template <>
+inline float32x4x2_t convolve_3x3<2>(const float *in_top, const float *in_mid, const float *in_low, const float32x4x3_t &m0, const float32x4x3_t &m1, const float32x4x3_t &m2, int fixed_point_position)
+{
+    float32x4x2_t out = convolve_3x3<1>(in_top, in_mid, in_low, m0, m1, m2, fixed_point_position);
+    out.val[0]        = vsetq_lane_f32(vgetq_lane_f32(out.val[0], 2), out.val[0], 1);
+    out.val[0]        = vsetq_lane_f32(vgetq_lane_f32(out.val[1], 0), out.val[0], 2);
+    out.val[0]        = vsetq_lane_f32(vgetq_lane_f32(out.val[1], 2), out.val[0], 3);
+    return out;
+}
+
+template <>
+inline float32x4x2_t convolve_3x3<3>(const float *in_top, const float *in_mid, const float *in_low, const float32x4x3_t &m0, const float32x4x3_t &m1, const float32x4x3_t &m2, int fixed_point_position)
+{
+    float32x4x2_t out = convolve_3x3<1>(in_top, in_mid, in_low, m0, m1, m2, fixed_point_position);
+    out.val[0]        = vsetq_lane_f32(vgetq_lane_f32(out.val[0], 3), out.val[0], 1);
+    return out;
+}
+
+/** Perform a convolve3x3 on qint16.
+ *
+ * @param[in] in_top               Pointer to the first row of the input.
+ * @param[in] in_mid               Pointer to the second row of the input.
+ * @param[in] in_low               Pointer to the third row of the input.
+ * @param[in] m0                   First row of the filter.
+ * @param[in] m1                   Second row of the filter.
+ * @param[in] m2                   Third row of the filter.
+ * @param[in] fixed_point_position (Optional) Fixed point position.
+ *
+ */
+template <unsigned int stridex>
+qint16x8x2_t convolve_3x3(const qint8_t *in_top, const qint8_t *in_mid, const qint8_t *in_low, const qint8x8x3_t &m0, const qint8x8x3_t &m1, const qint8x8x3_t &m2, int fixed_point_position);
+
+template <>
+inline qint16x8x2_t convolve_3x3<1>(const qint8_t *in_top, const qint8_t *in_mid, const qint8_t *in_low, const qint8x8x3_t &m0, const qint8x8x3_t &m1, const qint8x8x3_t &m2, int fixed_point_position)
+{
+    ARM_COMPUTE_UNUSED(fixed_point_position);
+
+    const qint8x8x3_t vtop =
+    {
+        {
+            vld1_qs8(in_top),
+            vld1_qs8(in_top + 8),
+            vld1_qs8(in_top + 16)
+        }
+    };
+    const qint8x8x3_t vmid =
+    {
+        {
+            vld1_qs8(in_mid),
+            vld1_qs8(in_mid + 8),
+            vld1_qs8(in_mid + 16)
+        }
+    };
+    const qint8x8x3_t vlow =
+    {
+        {
+            vld1_qs8(in_low),
+            vld1_qs8(in_low + 8),
+            vld1_qs8(in_low + 16)
+        }
+    };
+    qint16x8x2_t out =
+    {
+        {
+            vmull_qs8(vtop.val[0], m0.val[0], fixed_point_position),
+            vmull_qs8(vtop.val[1], m0.val[0], fixed_point_position)
+        }
+    };
+    out.val[0] = vqmlal_qs8(out.val[0], vext_s8(vtop.val[0], vtop.val[1], 1), m0.val[1], fixed_point_position);
+    out.val[0] = vqmlal_qs8(out.val[0], vext_s8(vtop.val[0], vtop.val[1], 2), m0.val[2], fixed_point_position);
+    out.val[0] = vqmlal_qs8(out.val[0], vmid.val[0], m1.val[0], fixed_point_position);
+    out.val[0] = vqmlal_qs8(out.val[0], vext_s8(vmid.val[0], vmid.val[1], 1), m1.val[1], fixed_point_position);
+    out.val[0] = vqmlal_qs8(out.val[0], vext_s8(vmid.val[0], vmid.val[1], 2), m1.val[2], fixed_point_position);
+    out.val[0] = vqmlal_qs8(out.val[0], vlow.val[0], m2.val[0], fixed_point_position);
+    out.val[0] = vqmlal_qs8(out.val[0], vext_s8(vlow.val[0], vlow.val[1], 1), m2.val[1], fixed_point_position);
+    out.val[0] = vqmlal_qs8(out.val[0], vext_s8(vlow.val[0], vlow.val[1], 2), m2.val[2], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vext_s8(vtop.val[1], vtop.val[2], 1), m0.val[1], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vext_s8(vtop.val[1], vtop.val[2], 2), m0.val[2], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vmid.val[1], m1.val[0], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vext_s8(vmid.val[1], vmid.val[2], 1), m1.val[1], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vext_s8(vmid.val[1], vmid.val[2], 2), m1.val[2], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vlow.val[1], m2.val[0], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vext_s8(vlow.val[1], vlow.val[2], 1), m2.val[1], fixed_point_position);
+    out.val[1] = vqmlal_qs8(out.val[1], vext_s8(vlow.val[1], vlow.val[2], 2), m2.val[2], fixed_point_position);
+    return out;
+}
+
+template <>
+inline qint16x8x2_t convolve_3x3<2>(const qint8_t *in_top, const qint8_t *in_mid, const qint8_t *in_low, const qint8x8x3_t &m0, const qint8x8x3_t &m1, const qint8x8x3_t &m2, int fixed_point_position)
+{
+    qint16x8x2_t out = convolve_3x3<1>(in_top, in_mid, in_low, m0, m1, m2, fixed_point_position);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[0], 2), out.val[0], 1);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[0], 4), out.val[0], 2);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[0], 6), out.val[0], 3);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[1], 0), out.val[0], 4);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[1], 2), out.val[0], 5);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[1], 4), out.val[0], 6);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[1], 6), out.val[0], 7);
+    return out;
+}
+
+template <>
+inline qint16x8x2_t convolve_3x3<3>(const qint8_t *in_top, const qint8_t *in_mid, const qint8_t *in_low, const qint8x8x3_t &m0, const qint8x8x3_t &m1, const qint8x8x3_t &m2, int fixed_point_position)
+{
+    qint16x8x2_t out = convolve_3x3<1>(in_top, in_mid, in_low, m0, m1, m2, fixed_point_position);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[0], 3), out.val[0], 1);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[0], 6), out.val[0], 2);
+    out.val[0]       = vsetq_lane_s16(vgetq_lane_s16(out.val[1], 1), out.val[0], 3);
+    return out;
+}
+
+/** Stores a float32x4x2_t array into a memory location.
+ *
+ * @param[in] buffer Pointer to the memory location where the values will be stored.
+ * @param[in] values Values that will be stored.
+ *
+ */
+template <unsigned int stridex>
+void store_results(float *buffer, const float32x4x2_t &values);
+
+template <>
+inline void store_results<1>(float *buffer, const float32x4x2_t &values)
+{
+    vst1q_f32(buffer, values.val[0]);
+    vst1q_f32(buffer + 4, values.val[1]);
+}
+
+template <>
+inline void store_results<2>(float *buffer, const float32x4x2_t &values)
+{
+    vst1q_f32(buffer, values.val[0]);
+}
+
+template <>
+inline void store_results<3>(float *buffer, const float32x4x2_t &values)
+{
+    vst1_f32(buffer, vget_low_f32(values.val[0]));
+}
+
+/** Stores a qint16_t array into a memory location.
+ *
+ * @param[in] buffer Pointer to the memory location where the values will be stored.
+ * @param[in] values Values that will be stored.
+ *
+ */
+template <unsigned int stridex>
+void store_results(qint16_t *buffer, const qint16x8x2_t &values);
+
+template <>
+inline void store_results<1>(qint16_t *buffer, const qint16x8x2_t &values)
+{
+    vst1q_qs16(buffer, values.val[0]);
+    vst1q_qs16(buffer + 8, values.val[1]);
+}
+
+template <>
+inline void store_results<2>(qint16_t *buffer, const qint16x8x2_t &values)
+{
+    vst1q_qs16(buffer, values.val[0]);
+}
+
+template <>
+inline void store_results<3>(qint16_t *buffer, const qint16x8x2_t &values)
+{
+    vst1_qs16(buffer, vget_low_s16(values.val[0]));
+}
+
+#ifdef ARM_COMPUTE_AARCH64_V8_2
+/** Loads a 3x3 matrix as a row (float16_t).
+ *
+ * @param[in] ptr Pointer to a float 3x3 matrix.
+ *
+ * @return The loaded matrix.
+ */
+inline float16x8x3_t load_matrix_row(const float16_t *ptr)
+{
+    /* ptr is a pointer to a row in a 3x3 matrix, the function returns 3 vectors holding exactly the same value in all lanes:
+       r.val[0] contains the first element, r.val[1] the second element and r.val[2] the third element (in all lanes) */
+    const float16x8x3_t r =
+    {
+        {
+            vld1q_dup_f16(ptr),
+            vld1q_dup_f16(1 + ptr),
+            vld1q_dup_f16(2 + ptr)
+        }
+    };
+    return r;
+}
+
+/** Perform a convolve3x3 on float16.
+ *
+ * @param[in] in_top               Pointer to the first row of the input.
+ * @param[in] in_mid               Pointer to the second row of the input.
+ * @param[in] in_low               Pointer to the third row of the input.
+ * @param[in] m0                   First row of the filter.
+ * @param[in] m1                   Second row of the filter.
+ * @param[in] m2                   Third row of the filter.
+ * @param[in] fixed_point_position (Optional) Fixed point position.
+ *
+ */
+template <unsigned int stridex>
+float16x8x2_t convolve_3x3(const float16_t *in_top, const float16_t *in_mid, const float16_t *in_low, const float16x8x3_t &m0, const float16x8x3_t &m1, const float16x8x3_t &m2,
+                           int fixed_point_position);
+
+template <>
+inline float16x8x2_t convolve_3x3<1>(const float16_t *in_top, const float16_t *in_mid, const float16_t *in_low, const float16x8x3_t &m0, const float16x8x3_t &m1, const float16x8x3_t &m2,
+                                     int fixed_point_position)
+{
+    ARM_COMPUTE_UNUSED(fixed_point_position);
+
+    const float16x8x3_t vtop =
+    {
+        {
+            vld1q_f16(in_top),
+            vld1q_f16(in_top + 8),
+            vld1q_f16(in_top + 16)
+        }
+    };
+    const float16x8x3_t vmid =
+    {
+        {
+            vld1q_f16(in_mid),
+            vld1q_f16(in_mid + 8),
+            vld1q_f16(in_mid + 16)
+        }
+    };
+    const float16x8x3_t vlow =
+    {
+        {
+            vld1q_f16(in_low),
+            vld1q_f16(in_low + 8),
+            vld1q_f16(in_low + 16)
+        }
+    };
+    float16x8x2_t out =
+    {
+        {
+            vmulq_f16(vtop.val[0], m0.val[0]),
+            vmulq_f16(vtop.val[1], m0.val[0])
+        }
+    };
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vextq_f16(vtop.val[0], vtop.val[1], 1), m0.val[1]));
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vextq_f16(vtop.val[0], vtop.val[1], 2), m0.val[2]));
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vmid.val[0], m1.val[0]));
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vextq_f16(vmid.val[0], vmid.val[1], 1), m1.val[1]));
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vextq_f16(vmid.val[0], vmid.val[1], 2), m1.val[2]));
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vlow.val[0], m2.val[0]));
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vextq_f16(vlow.val[0], vlow.val[1], 1), m2.val[1]));
+    out.val[0] = vaddq_f16(out.val[0], vmulq_f16(vextq_f16(vlow.val[0], vlow.val[1], 2), m2.val[2]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vextq_f16(vtop.val[1], vtop.val[2], 1), m0.val[1]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vextq_f16(vtop.val[1], vtop.val[2], 2), m0.val[2]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vmid.val[1], m1.val[0]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vextq_f16(vmid.val[1], vmid.val[2], 1), m1.val[1]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vextq_f16(vmid.val[1], vmid.val[2], 2), m1.val[2]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vlow.val[1], m2.val[0]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vextq_f16(vlow.val[1], vlow.val[2], 1), m2.val[1]));
+    out.val[1] = vaddq_f16(out.val[1], vmulq_f16(vextq_f16(vlow.val[1], vlow.val[2], 2), m2.val[2]));
+    return out;
+}
+
+template <>
+inline float16x8x2_t convolve_3x3<2>(const float16_t *in_top, const float16_t *in_mid, const float16_t *in_low, const float16x8x3_t &m0, const float16x8x3_t &m1, const float16x8x3_t &m2,
+                                     int fixed_point_position)
+{
+    float16x8x2_t out = convolve_3x3<1>(in_top, in_mid, in_low, m0, m1, m2, fixed_point_position);
+    out.val[0]        = vsetq_lane_f16(vgetq_lane_f16(out.val[0], 2), out.val[0], 1);
+    out.val[0]        = vsetq_lane_f16(vgetq_lane_f16(out.val[1], 0), out.val[0], 2);
+    out.val[0]        = vsetq_lane_f16(vgetq_lane_f16(out.val[1], 2), out.val[0], 3);
+    return out;
+}
+
+template <>
+inline float16x8x2_t convolve_3x3<3>(const float16_t *in_top, const float16_t *in_mid, const float16_t *in_low, const float16x8x3_t &m0, const float16x8x3_t &m1, const float16x8x3_t &m2,
+                                     int fixed_point_position)
+{
+    float16x8x2_t out = convolve_3x3<1>(in_top, in_mid, in_low, m0, m1, m2, fixed_point_position);
+    out.val[0]        = vsetq_lane_f16(vgetq_lane_f16(out.val[0], 3), out.val[0], 1);
+    return out;
+}
+
+/** Stores a float16x8x2_t array into a memory location.
+ *
+ * @param[in] buffer Pointer to the memory location where the values will be stored.
+ * @param[in] values Values that will be stored.
+ *
+ */
+template <unsigned int stridex>
+void store_results(float16_t *buffer, const float16x8x2_t &values);
+
+template <>
+inline void store_results<1>(float16_t *buffer, const float16x8x2_t &values)
+{
+    vst1q_f16(buffer, values.val[0]);
+    vst1q_f16(buffer + 8, values.val[1]);
+}
+
+template <>
+inline void store_results<2>(float16_t *buffer, const float16x8x2_t &values)
+{
+    vst1q_f16(buffer, values.val[0]);
+}
+
+template <>
+inline void store_results<3>(float16_t *buffer, const float16x8x2_t &values)
+{
+    vst1_f16(buffer, vget_low_f16(values.val[0]));
+}
+#endif /* ARM_COMPUTE_AARCH64_V8_2 */
+
+/** Get the number of elements processed on 3x3 convolution.
+ *
+ * @param[in] num_elems_written_per_iteration Number of elements written per iteration on 3x3 convolution.
+ *
+ * @return The number of elements processed.
+ */
+template <unsigned int stridex>
+int get_input_num_elems_processed(unsigned int num_elems_written_per_iteration);
+
+template <>
+inline int get_input_num_elems_processed<1>(unsigned int num_elems_written_per_iteration)
+{
+    return num_elems_written_per_iteration;
+}
+
+template <>
+inline int get_input_num_elems_processed<2>(unsigned int num_elems_written_per_iteration)
+{
+    return num_elems_written_per_iteration << 1;
+}
+
+template <>
+inline int get_input_num_elems_processed<3>(unsigned int num_elems_written_per_iteration)
+{
+    return num_elems_written_per_iteration * 3;
+}
+}
+} // namespace arm_compute
+#endif /* __ARM_COMPUTE_NEDIRECTCONVOLUTIONDETAIL_H__ */
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