src/cpu/kernels/activation/generic/neon/qasymm8.cpp

/*
 * Copyright (c) 2020-2022 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.
 */

#include "arm_compute/core/Helpers.h"
#include "arm_compute/core/Window.h"
#include "src/core/NEON/NEAsymm.h"
#include "src/core/NEON/NEMath.h"
#include "src/core/NEON/wrapper/wrapper.h"

#include <arm_neon.h>
#include <cmath>
#include <cstddef>
#include <cstdint>

namespace arm_compute
{
namespace cpu
{
namespace
{
#ifdef __aarch64__

void substitute_bytes_neon(
    const uint8_t        *table,
    size_t                num_strings,
    size_t                string_length,
    const uint8_t *const *input,
    uint8_t *const       *output)
{
    __asm__ __volatile__(
        "ldr q16, [%x[table], #0x0]\n"
        "ldr q17, [%x[table], #0x10]\n"
        "mov x22, #0x0\n"
        "ldr q18, [%x[table], #0x20]\n"
        "ldr q19, [%x[table], #0x30]\n"
        "ldr q20, [%x[table], #0x40]\n"
        "ldr q21, [%x[table], #0x50]\n"
        "ldr q22, [%x[table], #0x60]\n"
        "ldr q23, [%x[table], #0x70]\n"
        "ldr q24, [%x[table], #0x80]\n"
        "ldr q25, [%x[table], #0x90]\n"
        "ldr q26, [%x[table], #0xa0]\n"
        "ldr q27, [%x[table], #0xb0]\n"
        "ldr q28, [%x[table], #0xc0]\n"
        "ldr q29, [%x[table], #0xd0]\n"
        "ldr q30, [%x[table], #0xe0]\n"
        "ldr q31, [%x[table], #0xf0]\n"
        "1:" // string loop
        "ldr x21, [%x[input], x22, LSL #0x3]\n"
        "ldr x20, [%x[output], x22, LSL #0x3]\n"
        "movi v12.16b, #0x40\n"
        "movi v11.16b, #0x80\n"
        "movi v10.16b, #0xc0\n"
        "mov x19, %x[string_length]\n"
        "2:" // 4 rounds: width loop
        "cmp x19, #0x30\n"
        "bge 27f\n"
        "tbz x19, #5, 10f\n"
        "ld1 { v9.16b }, [x21], #0x10\n"
        "ld1 { v13.16b }, [x21], #0x10\n"
        "tbz x19, #3, 6f\n"
        "ldr d14, [x21], #0x8\n"
        "tbz x19, #2, 4f\n"
        "ld1 { v14.s }[2], [x21], #0x4\n"
        "tbz x19, #1, 3f\n"
        "ld1 { v14.h }[6], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v14.b }[14], [x21]\n"
        "b 26f\n"
        "3:" // 4 rounds: Partial load: partial_1_44
        "tbz x19, #0, 26f\n"
        "ld1 { v14.b }[12], [x21]\n"
        "b 26f\n"
        "4:" // 4 rounds: Partial load: partial_2_40
        "tbz x19, #1, 5f\n"
        "ld1 { v14.h }[4], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v14.b }[10], [x21]\n"
        "b 26f\n"
        "5:" // 4 rounds: Partial load: partial_1_40
        "tbz x19, #0, 26f\n"
        "ld1 { v14.b }[8], [x21]\n"
        "b 26f\n"
        "6:" // 4 rounds: Partial load: partial_4_32
        "tbz x19, #2, 8f\n"
        "ldr s14, [x21], #0x4\n"
        "tbz x19, #1, 7f\n"
        "ld1 { v14.h }[2], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v14.b }[6], [x21]\n"
        "b 26f\n"
        "7:" // 4 rounds: Partial load: partial_1_36
        "tbz x19, #0, 26f\n"
        "ld1 { v14.b }[4], [x21]\n"
        "b 26f\n"
        "8:" // 4 rounds: Partial load: partial_2_32
        "tbz x19, #1, 9f\n"
        "ldr h14, [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v14.b }[2], [x21]\n"
        "b 26f\n"
        "9:" // 4 rounds: Partial load: partial_1_32
        "tbz x19, #0, 26f\n"
        "ldr b14, [x21, #0x0]\n"
        "b 26f\n"
        "10:" // 4 rounds: Partial load: partial_16_0
        "tbz x19, #4, 18f\n"
        "ld1 { v9.16b }, [x21], #0x10\n"
        "tbz x19, #3, 14f\n"
        "ldr d13, [x21], #0x8\n"
        "tbz x19, #2, 12f\n"
        "ld1 { v13.s }[2], [x21], #0x4\n"
        "tbz x19, #1, 11f\n"
        "ld1 { v13.h }[6], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v13.b }[14], [x21]\n"
        "b 26f\n"
        "11:" // 4 rounds: Partial load: partial_1_28
        "tbz x19, #0, 26f\n"
        "ld1 { v13.b }[12], [x21]\n"
        "b 26f\n"
        "12:" // 4 rounds: Partial load: partial_2_24
        "tbz x19, #1, 13f\n"
        "ld1 { v13.h }[4], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v13.b }[10], [x21]\n"
        "b 26f\n"
        "13:" // 4 rounds: Partial load: partial_1_24
        "tbz x19, #0, 26f\n"
        "ld1 { v13.b }[8], [x21]\n"
        "b 26f\n"
        "14:" // 4 rounds: Partial load: partial_4_16
        "tbz x19, #2, 16f\n"
        "ldr s13, [x21], #0x4\n"
        "tbz x19, #1, 15f\n"
        "ld1 { v13.h }[2], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v13.b }[6], [x21]\n"
        "b 26f\n"
        "15:" // 4 rounds: Partial load: partial_1_20
        "tbz x19, #0, 26f\n"
        "ld1 { v13.b }[4], [x21]\n"
        "b 26f\n"
        "16:" // 4 rounds: Partial load: partial_2_16
        "tbz x19, #1, 17f\n"
        "ldr h13, [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v13.b }[2], [x21]\n"
        "b 26f\n"
        "17:" // 4 rounds: Partial load: partial_1_16
        "tbz x19, #0, 26f\n"
        "ldr b13, [x21, #0x0]\n"
        "b 26f\n"
        "18:" // 4 rounds: Partial load: partial_8_0
        "tbz x19, #3, 22f\n"
        "ldr d9, [x21], #0x8\n"
        "tbz x19, #2, 20f\n"
        "ld1 { v9.s }[2], [x21], #0x4\n"
        "tbz x19, #1, 19f\n"
        "ld1 { v9.h }[6], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v9.b }[14], [x21]\n"
        "b 26f\n"
        "19:" // 4 rounds: Partial load: partial_1_12
        "tbz x19, #0, 26f\n"
        "ld1 { v9.b }[12], [x21]\n"
        "b 26f\n"
        "20:" // 4 rounds: Partial load: partial_2_8
        "tbz x19, #1, 21f\n"
        "ld1 { v9.h }[4], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v9.b }[10], [x21]\n"
        "b 26f\n"
        "21:" // 4 rounds: Partial load: partial_1_8
        "tbz x19, #0, 26f\n"
        "ld1 { v9.b }[8], [x21]\n"
        "b 26f\n"
        "22:" // 4 rounds: Partial load: partial_4_0
        "tbz x19, #2, 24f\n"
        "ldr s9, [x21], #0x4\n"
        "tbz x19, #1, 23f\n"
        "ld1 { v9.h }[2], [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v9.b }[6], [x21]\n"
        "b 26f\n"
        "23:" // 4 rounds: Partial load: partial_1_4
        "tbz x19, #0, 26f\n"
        "ld1 { v9.b }[4], [x21]\n"
        "b 26f\n"
        "24:" // 4 rounds: Partial load: partial_2_0
        "tbz x19, #1, 25f\n"
        "ldr h9, [x21], #0x2\n"
        "tbz x19, #0, 26f\n"
        "ld1 { v9.b }[2], [x21]\n"
        "b 26f\n"
        "25:" // 4 rounds: Partial load: partial_1_0
        "ldr b9, [x21, #0x0]\n"
        "26:" // 4 rounds: Partial load: Done
        "b 28f\n"
        "27:" // 4 rounds: Full load
        "ldr q9, [x21, #0x0]\n"
        "ldr q13, [x21, #0x10]\n"
        "ldr q14, [x21, #0x20]\n"
        "add x21, x21, #0x30\n"
        "28:" // 4 rounds: Load done
        "sub v8.16b, v9.16b, v12.16b\n"
        "sub v7.16b, v9.16b, v11.16b\n"
        "tbl v8.16b, { v20.16b, v21.16b, v22.16b, v23.16b }, v8.16b\n"
        "sub v6.16b, v9.16b, v10.16b\n"
        "sub v5.16b, v13.16b, v12.16b\n"
        "tbl v9.16b, { v16.16b, v17.16b, v18.16b, v19.16b }, v9.16b\n"
        "sub v4.16b, v13.16b, v11.16b\n"
        "sub v3.16b, v13.16b, v10.16b\n"
        "tbl v7.16b, { v24.16b, v25.16b, v26.16b, v27.16b }, v7.16b\n"
        "sub v2.16b, v14.16b, v12.16b\n"
        "sub v1.16b, v14.16b, v11.16b\n"
        "tbl v6.16b, { v28.16b, v29.16b, v30.16b, v31.16b }, v6.16b\n"
        "sub v0.16b, v14.16b, v10.16b\n"
        "tbl v13.16b, { v16.16b, v17.16b, v18.16b, v19.16b }, v13.16b\n"
        "tbl v5.16b, { v20.16b, v21.16b, v22.16b, v23.16b }, v5.16b\n"
        "tbl v4.16b, { v24.16b, v25.16b, v26.16b, v27.16b }, v4.16b\n"
        "tbl v3.16b, { v28.16b, v29.16b, v30.16b, v31.16b }, v3.16b\n"
        "orr v9.16b, v9.16b, v8.16b\n"
        "tbl v14.16b, { v16.16b, v17.16b, v18.16b, v19.16b }, v14.16b\n"
        "tbl v2.16b, { v20.16b, v21.16b, v22.16b, v23.16b }, v2.16b\n"
        "orr v7.16b, v7.16b, v6.16b\n"
        "tbl v1.16b, { v24.16b, v25.16b, v26.16b, v27.16b }, v1.16b\n"
        "tbl v0.16b, { v28.16b, v29.16b, v30.16b, v31.16b }, v0.16b\n"
        "orr v13.16b, v13.16b, v5.16b\n"
        "orr v4.16b, v4.16b, v3.16b\n"
        "orr v14.16b, v14.16b, v2.16b\n"
        "cmp x19, #0x30\n"
        "orr v1.16b, v1.16b, v0.16b\n"
        "orr v9.16b, v9.16b, v7.16b\n"
        "orr v13.16b, v13.16b, v4.16b\n"
        "orr v14.16b, v14.16b, v1.16b\n"
        "bge 53f\n"
        "tbz x19, #5, 36f\n"
        "st1 { v9.16b }, [x20], #0x10\n"
        "st1 { v13.16b }, [x20], #0x10\n"
        "tbz x19, #3, 32f\n"
        "str d14, [x20], #0x8\n"
        "tbz x19, #2, 30f\n"
        "st1 { v14.s }[2], [x20], #0x4\n"
        "tbz x19, #1, 29f\n"
        "st1 { v14.h }[6], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v14.b }[14], [x20]\n"
        "b 52f\n"
        "29:" // 4 rounds: Partial writeback: partial_1_44
        "tbz x19, #0, 52f\n"
        "st1 { v14.b }[12], [x20]\n"
        "b 52f\n"
        "30:" // 4 rounds: Partial writeback: partial_2_40
        "tbz x19, #1, 31f\n"
        "st1 { v14.h }[4], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v14.b }[10], [x20]\n"
        "b 52f\n"
        "31:" // 4 rounds: Partial writeback: partial_1_40
        "tbz x19, #0, 52f\n"
        "st1 { v14.b }[8], [x20]\n"
        "b 52f\n"
        "32:" // 4 rounds: Partial writeback: partial_4_32
        "tbz x19, #2, 34f\n"
        "str s14, [x20], #0x4\n"
        "tbz x19, #1, 33f\n"
        "st1 { v14.h }[2], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v14.b }[6], [x20]\n"
        "b 52f\n"
        "33:" // 4 rounds: Partial writeback: partial_1_36
        "tbz x19, #0, 52f\n"
        "st1 { v14.b }[4], [x20]\n"
        "b 52f\n"
        "34:" // 4 rounds: Partial writeback: partial_2_32
        "tbz x19, #1, 35f\n"
        "str h14, [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v14.b }[2], [x20]\n"
        "b 52f\n"
        "35:" // 4 rounds: Partial writeback: partial_1_32
        "tbz x19, #0, 52f\n"
        "str b14, [x20, #0x0]\n"
        "b 52f\n"
        "36:" // 4 rounds: Partial writeback: partial_16_0
        "tbz x19, #4, 44f\n"
        "st1 { v9.16b }, [x20], #0x10\n"
        "tbz x19, #3, 40f\n"
        "str d13, [x20], #0x8\n"
        "tbz x19, #2, 38f\n"
        "st1 { v13.s }[2], [x20], #0x4\n"
        "tbz x19, #1, 37f\n"
        "st1 { v13.h }[6], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v13.b }[14], [x20]\n"
        "b 52f\n"
        "37:" // 4 rounds: Partial writeback: partial_1_28
        "tbz x19, #0, 52f\n"
        "st1 { v13.b }[12], [x20]\n"
        "b 52f\n"
        "38:" // 4 rounds: Partial writeback: partial_2_24
        "tbz x19, #1, 39f\n"
        "st1 { v13.h }[4], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v13.b }[10], [x20]\n"
        "b 52f\n"
        "39:" // 4 rounds: Partial writeback: partial_1_24
        "tbz x19, #0, 52f\n"
        "st1 { v13.b }[8], [x20]\n"
        "b 52f\n"
        "40:" // 4 rounds: Partial writeback: partial_4_16
        "tbz x19, #2, 42f\n"
        "str s13, [x20], #0x4\n"
        "tbz x19, #1, 41f\n"
        "st1 { v13.h }[2], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v13.b }[6], [x20]\n"
        "b 52f\n"
        "41:" // 4 rounds: Partial writeback: partial_1_20
        "tbz x19, #0, 52f\n"
        "st1 { v13.b }[4], [x20]\n"
        "b 52f\n"
        "42:" // 4 rounds: Partial writeback: partial_2_16
        "tbz x19, #1, 43f\n"
        "str h13, [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v13.b }[2], [x20]\n"
        "b 52f\n"
        "43:" // 4 rounds: Partial writeback: partial_1_16
        "tbz x19, #0, 52f\n"
        "str b13, [x20, #0x0]\n"
        "b 52f\n"
        "44:" // 4 rounds: Partial writeback: partial_8_0
        "tbz x19, #3, 48f\n"
        "str d9, [x20], #0x8\n"
        "tbz x19, #2, 46f\n"
        "st1 { v9.s }[2], [x20], #0x4\n"
        "tbz x19, #1, 45f\n"
        "st1 { v9.h }[6], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v9.b }[14], [x20]\n"
        "b 52f\n"
        "45:" // 4 rounds: Partial writeback: partial_1_12
        "tbz x19, #0, 52f\n"
        "st1 { v9.b }[12], [x20]\n"
        "b 52f\n"
        "46:" // 4 rounds: Partial writeback: partial_2_8
        "tbz x19, #1, 47f\n"
        "st1 { v9.h }[4], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v9.b }[10], [x20]\n"
        "b 52f\n"
        "47:" // 4 rounds: Partial writeback: partial_1_8
        "tbz x19, #0, 52f\n"
        "st1 { v9.b }[8], [x20]\n"
        "b 52f\n"
        "48:" // 4 rounds: Partial writeback: partial_4_0
        "tbz x19, #2, 50f\n"
        "str s9, [x20], #0x4\n"
        "tbz x19, #1, 49f\n"
        "st1 { v9.h }[2], [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v9.b }[6], [x20]\n"
        "b 52f\n"
        "49:" // 4 rounds: Partial writeback: partial_1_4
        "tbz x19, #0, 52f\n"
        "st1 { v9.b }[4], [x20]\n"
        "b 52f\n"
        "50:" // 4 rounds: Partial writeback: partial_2_0
        "tbz x19, #1, 51f\n"
        "str h9, [x20], #0x2\n"
        "tbz x19, #0, 52f\n"
        "st1 { v9.b }[2], [x20]\n"
        "b 52f\n"
        "51:" // 4 rounds: Partial writeback: partial_1_0
        "str b9, [x20, #0x0]\n"
        "52:" // 4 rounds: Partial writeback: Done
        "b 54f\n"
        "53:" // 4 rounds: Full writeback
        "str q9, [x20, #0x0]\n"
        "str q13, [x20, #0x10]\n"
        "str q14, [x20, #0x20]\n"
        "add x20, x20, #0x30\n"
        "54:" // 4 rounds: Writeback done
        "subs x19, x19, #0x30\n"
        "bgt 2b\n"
        "add x22, x22, #0x1\n"
        "cmp x22, %x[num_strings]\n"
        "bne 1b\n"
        :
        : [input] "r"(input), [num_strings] "r"(num_strings), [output] "r"(output), [string_length] "r"(string_length), [table] "r"(table)
        : "cc", "memory", "v0", "v1", "v2", "v3", "v4", "v5", "v6", "v7", "v8", "v9", "v10", "v11", "v12", "v13", "v14", "v16", "v17", "v18", "v19", "v20", "v21", "v22", "v23", "v24", "v25", "v26", "v27", "v28", "v29", "v30", "v31", "x19", "x20", "x21", "x22");
}

#endif // __aarch64__
} // namespace

void neon_qasymm8_activation_lut(const ITensor *src, ITensor *dst, const ActivationLayerInfo &act_info, const Window &window)
{
    ARM_COMPUTE_ERROR_ON(!ActivationLayerInfo::is_lut_supported(act_info.activation(), src->info()->data_type()));
#ifdef __aarch64__
    const int window_step_x  = src->info()->tensor_shape().x();
    Window win_collapsed = window.collapse_if_possible(window, Window::DimZ);
    win_collapsed.set(Window::DimX, Window::Dimension(0, 1, 1));
    Iterator input(src, win_collapsed);
    Iterator output(dst, win_collapsed);
    execute_window_loop(win_collapsed, [&](const Coordinates &)
    {
        const auto input_ptr  = reinterpret_cast<const uint8_t *>(input.ptr());
        auto       output_ptr = reinterpret_cast<uint8_t *>(output.ptr());
        substitute_bytes_neon(act_info.lut().data(), 1u, window_step_x, &input_ptr, &output_ptr);
    },
    input, output);
#else  // #ifdef __aarch64__
    ARM_COMPUTE_UNUSED(src);
    ARM_COMPUTE_UNUSED(dst);
    ARM_COMPUTE_UNUSED(act_info);
    ARM_COMPUTE_UNUSED(window);
    ARM_COMPUTE_ERROR("LUT Only supported in aarch64.");
#endif // __aarch64__
}

void neon_qasymm8_activation(const ITensor *src, ITensor *dst, const ActivationLayerInfo &act_info, const Window &window)
{
    constexpr int                                 window_step_x  = 16;
    const auto                                    window_start_x = static_cast<int>(window.x().start());
    const auto                                    window_end_x   = static_cast<int>(window.x().end());
    const ActivationLayerInfo::ActivationFunction act            = act_info.activation();

    Window win_collapsed = window.collapse_if_possible(window, Window::DimZ);
    win_collapsed.set(Window::DimX, Window::Dimension(0, 1, 1));

    Iterator input(src, win_collapsed);
    Iterator output(dst, win_collapsed);

    const UniformQuantizationInfo qi_in    = src->info()->quantization_info().uniform();
    const UniformQuantizationInfo qi_out   = dst->info()->quantization_info().uniform();
    const qasymm8x16_t            va       = vdupq_n_u8(quantize_qasymm8(act_info.a(), qi_in));
    const qasymm8x16_t            vb       = vdupq_n_u8(quantize_qasymm8(act_info.b(), qi_in));
    const qasymm8_t               a        = quantize_qasymm8(act_info.a(), qi_in);
    const qasymm8_t               b        = quantize_qasymm8(act_info.b(), qi_in);
    const qasymm8_t               const_0  = quantize_qasymm8(0.f, qi_in);
    const qasymm8x16_t            vconst_0 = vdupq_n_u8(const_0);
    const auto                    vconst_1 = vdupq_n_f32(1.f);
#ifndef __aarch64__
    const auto vconst_0_f32 = vdupq_n_f32(0);
#endif // __aarch64__
    const float32x4_t va_f32 = vdupq_n_f32(act_info.a());
    const float32x4_t vb_f32 = vdupq_n_f32(act_info.b());
    const float       a_f32  = act_info.a();
    const float       b_f32  = act_info.b();

#ifndef __aarch64__
    const auto const_6_f32     = vdupq_n_f32(6.f);
    const auto const_0_f32     = vdupq_n_f32(0.f);
    const auto const_3_f32     = vdupq_n_f32(3.f);
    const auto const_inv_6_f32 = vdupq_n_f32(0.166666667f);
#endif // __aarch64__

    // Initialise scale/offset for re-quantization
    float       s  = qi_in.scale / qi_out.scale;
    float       o  = -qi_in.offset * s + qi_out.offset;
    float32x4_t vs = vdupq_n_f32(s);
    float32x4_t vo = vdupq_n_f32(o);

    execute_window_loop(win_collapsed, [&](const Coordinates &)
    {
        const auto input_ptr  = reinterpret_cast<const qasymm8_t *>(input.ptr());
        const auto output_ptr = reinterpret_cast<qasymm8_t *>(output.ptr());

        wrapper::traits::neon_bitvector_t<qasymm8_t, wrapper::traits::BitWidth::W128> tmp;

        // Compute S elements per iteration
        int x = window_start_x;
        for(; x <= (window_end_x - window_step_x); x += window_step_x)
        {
            const auto vin = wrapper::vloadq(input_ptr + x);
            if(act == ActivationLayerInfo::ActivationFunction::RELU)
            {
                // Perform activation
                tmp = vmaxq_u8(vconst_0, vin);
                // Re-quantize to new output space
                tmp = vmlaq_qasymm8(tmp, vs, vo);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::BOUNDED_RELU)
            {
                // Perform activation
                tmp = vminq_u8(va, vmaxq_u8(vconst_0, vin));
                // Re-quantize to new output space
                tmp = vmlaq_qasymm8(tmp, vs, vo);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU)
            {
                // Perform activation
                tmp = vminq_u8(va, vmaxq_u8(vb, vin));
                // Re-quantize to new output space
                tmp = vmlaq_qasymm8(tmp, vs, vo);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::LOGISTIC)
            {
                // De-quantize
                const auto vin_deq = vdequantize(vin, qi_in);
                // Perform activation
                const float32x4x4_t tmp_dep =
                {
                    {
                        wrapper::vdiv(vconst_1, wrapper::vadd(vconst_1, wrapper::vexpq(wrapper::vneg(vin_deq.val[0])))),
                        wrapper::vdiv(vconst_1, wrapper::vadd(vconst_1, wrapper::vexpq(wrapper::vneg(vin_deq.val[1])))),
                        wrapper::vdiv(vconst_1, wrapper::vadd(vconst_1, wrapper::vexpq(wrapper::vneg(vin_deq.val[2])))),
                        wrapper::vdiv(vconst_1, wrapper::vadd(vconst_1, wrapper::vexpq(wrapper::vneg(vin_deq.val[3])))),
                    }
                };
                // Re-quantize to new output space
                tmp = vquantize(tmp_dep, qi_out);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::TANH)
            {
                // De-quantize
                const auto vin_deq = vdequantize(vin, qi_in);
                // Perform activation
                const float32x4x4_t tmp_dep =
                {
                    {
                        wrapper::vmul(va_f32, wrapper::vtanh(wrapper::vmul(vin_deq.val[0], vb_f32))),
                        wrapper::vmul(va_f32, wrapper::vtanh(wrapper::vmul(vin_deq.val[1], vb_f32))),
                        wrapper::vmul(va_f32, wrapper::vtanh(wrapper::vmul(vin_deq.val[2], vb_f32))),
                        wrapper::vmul(va_f32, wrapper::vtanh(wrapper::vmul(vin_deq.val[3], vb_f32))),
                    }
                };
                // Re-quantize to new output space
                tmp = vquantize(tmp_dep, qi_out);
            }
#ifndef __aarch64__ // LUT-based implementation is used for aarch64 instead.
            else if(act == ActivationLayerInfo::ActivationFunction::HARD_SWISH)
            {
                // De-quantize
                const auto vin_deq = vdequantize(vin, qi_in);
                // Perform activation
                const float32x4x4_t tmp_dep =
                {
                    {
                        wrapper::vmul(vin_deq.val[0], wrapper::vmul(const_inv_6_f32, wrapper::vmin(const_6_f32, wrapper::vmax(const_0_f32, wrapper::vadd(vin_deq.val[0], const_3_f32))))),
                        wrapper::vmul(vin_deq.val[1], wrapper::vmul(const_inv_6_f32, wrapper::vmin(const_6_f32, wrapper::vmax(const_0_f32, wrapper::vadd(vin_deq.val[1], const_3_f32))))),
                        wrapper::vmul(vin_deq.val[2], wrapper::vmul(const_inv_6_f32, wrapper::vmin(const_6_f32, wrapper::vmax(const_0_f32, wrapper::vadd(vin_deq.val[2], const_3_f32))))),
                        wrapper::vmul(vin_deq.val[3], wrapper::vmul(const_inv_6_f32, wrapper::vmin(const_6_f32, wrapper::vmax(const_0_f32, wrapper::vadd(vin_deq.val[3], const_3_f32))))),
                    }
                };
                // Re-quantize to new output space
                tmp = vquantize(tmp_dep, qi_out);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::LEAKY_RELU)
            {
                const auto vin_deq = vdequantize(vin, qi_in);

                const uint32x4x4_t pos_mask =
                {
                    {
                        wrapper::vcgt(vin_deq.val[0], vconst_0_f32),
                        wrapper::vcgt(vin_deq.val[1], vconst_0_f32),
                        wrapper::vcgt(vin_deq.val[2], vconst_0_f32),
                        wrapper::vcgt(vin_deq.val[3], vconst_0_f32),
                    }
                };

                const float32x4x4_t tmp_dep =
                {
                    {
                        wrapper::vbsl(pos_mask.val[0], vin_deq.val[0], wrapper::vmul(va_f32, vin_deq.val[0])),
                        wrapper::vbsl(pos_mask.val[1], vin_deq.val[1], wrapper::vmul(va_f32, vin_deq.val[1])),
                        wrapper::vbsl(pos_mask.val[2], vin_deq.val[2], wrapper::vmul(va_f32, vin_deq.val[2])),
                        wrapper::vbsl(pos_mask.val[3], vin_deq.val[3], wrapper::vmul(va_f32, vin_deq.val[3])),
                    }
                };

                tmp = vquantize(tmp_dep, qi_out);
            }
#endif // __aarch64__
            else
            {
                ARM_COMPUTE_ERROR("Unsupported activation function");
            }
            wrapper::vstore(output_ptr + x, tmp);
        }

        // Compute left-over elements
        for(; x < window_end_x; ++x)
        {
            qasymm8_t in  = *(reinterpret_cast<const qasymm8_t *>(input_ptr + x));
            qasymm8_t tmp = 0;
            if(act == ActivationLayerInfo::ActivationFunction::RELU)
            {
                tmp = std::max(const_0, in);
                tmp = utility::clamp<int32_t, qasymm8_t>(tmp * s + o);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::BOUNDED_RELU)
            {
                tmp = std::min(a, std::max(const_0, in));
                tmp = utility::clamp<int32_t, qasymm8_t>(tmp * s + o);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::LU_BOUNDED_RELU)
            {
                tmp = std::min(a, std::max(b, in));
                tmp = utility::clamp<int32_t, qasymm8_t>(tmp * s + o);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::LOGISTIC)
            {
                float tmp_f = dequantize_qasymm8(in, qi_in);
                tmp_f       = 1.f / (1.f + std::exp(-tmp_f));
                tmp         = quantize_qasymm8(tmp_f, qi_out);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::TANH)
            {
                float tmp_f = dequantize_qasymm8(in, qi_in);
                tmp_f       = a_f32 * std::tanh(b_f32 * tmp_f);
                tmp         = quantize_qasymm8(tmp_f, qi_out);
            }
#ifndef __aarch64__ // LUT-based implementation is used for aarch64 instead.
            else if(act == ActivationLayerInfo::ActivationFunction::HARD_SWISH)
            {
                float tmp_f = dequantize_qasymm8(in, qi_in);
                tmp_f       = tmp_f * ((std::min(std::max((tmp_f + 3), 0.0f), 6.0f)) * 0.166666667f);
                tmp         = quantize_qasymm8(tmp_f, qi_out);
            }
            else if(act == ActivationLayerInfo::ActivationFunction::LEAKY_RELU)
            {
                float tmp_f = dequantize_qasymm8(in, qi_in);
                tmp_f       = tmp_f > 0 ? tmp_f : tmp_f * a_f32;
                tmp         = quantize_qasymm8(tmp_f, qi_out);
            }
#endif // __aarch64__
            else
            {
                ARM_COMPUTE_ERROR("Unsupported activation function");
            }
            *(output_ptr + x) = tmp;
        }
    },
    input, output);
}
} // namespace cpu
} // namespace arm_compute