Add SME2 implementation of softmax for FP16

In addition to the softmax kernel, this patch fixes minor issues in the fp32 implementation.

Resolves: COMPMID-6920

Change-Id: Ibbd9f0af5f2a93fba0e92d72ba437279c34149d3
Reviewed-on: https://review.mlplatform.org/c/ml/ComputeLibrary/+/11402
Benchmark: Arm Jenkins <bsgcomp@arm.com>
Tested-by: Arm Jenkins <bsgcomp@arm.com>
Reviewed-by: Viet-Hoa Do <viet-hoa.do@arm.com>
Comments-Addressed: Arm Jenkins <bsgcomp@arm.com>

11 files changed, 831 insertions, 29 deletions

diff --git a/docs/user_guide/release_version_and_change_log.dox b/docs/user_guide/release_version_and_change_log.dox
index b8910c9237..9da4956c43 100644
--- a/docs/user_guide/release_version_and_change_log.dox
+++ b/docs/user_guide/release_version_and_change_log.dox
@@ -45,7 +45,7 @@ v24.04 Public major release
  - Add Bfloat16 data type support for @ref NEMatMul.
  - Optimize start-up time of @ref NEConvolutionLayer for some input configurations where GeMM is selected as the convolution algorithm
  - Optimize @ref NEConvolutionLayer for input tensor size > 1e7 bytes and weight tensor height > 7
- - Add support for SoftMax in SME2 for FP32.
+ - Add support for SoftMax in SME2 for FP32 and FP16.
  - Performance optimizations:
    - Optimize @ref NESoftmaxLayer for axis != 0 by natively supporting higher axes up to axis 3.
  - Add support for in place accumulation to CPU GEMM kernels.
diff --git a/filelist.json b/filelist.json
index f6e85473c2..497da8e723 100644
--- a/filelist.json
+++ b/filelist.json
@@ -2238,7 +2238,8 @@
           },
           "sve2":{
             "common" :["src/cpu/kernels/softmax/generic/sve2/impl.cpp"],
-            "fp32" :["src/cpu/kernels/softmax/generic/sme2/fp32.cpp"]
+            "fp32" :["src/cpu/kernels/softmax/generic/sme2/fp32.cpp"],
+            "fp16" :["src/cpu/kernels/softmax/generic/sme2/fp16.cpp"]
           }
         }
       },
diff --git a/src/BUILD.bazel b/src/BUILD.bazel
index be6337a2c0..11d988338f 100644
--- a/src/BUILD.bazel
+++ b/src/BUILD.bazel
@@ -117,6 +117,7 @@ filegroup(
 	"cpu/kernels/elementwise_binary/generic/sve2/qasymm8_signed.cpp",
 	"cpu/kernels/elementwise_unary/generic/sve2/q8.cpp",
 	"cpu/kernels/lut/generic/sve2/u8.cpp",
+	"cpu/kernels/softmax/generic/sme2/fp16.cpp",
 	"cpu/kernels/softmax/generic/sme2/fp32.cpp",
 	"cpu/kernels/softmax/generic/sve2/impl.cpp"]  +
     glob(["**/*.h",
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index a1cba792b7..dbd3028859 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -335,6 +335,7 @@ target_sources(
 	cpu/kernels/elementwise_binary/generic/sve2/qasymm8_signed.cpp
 	cpu/kernels/elementwise_unary/generic/sve2/q8.cpp
 	cpu/kernels/lut/generic/sve2/u8.cpp
+	cpu/kernels/softmax/generic/sme2/fp16.cpp
 	cpu/kernels/softmax/generic/sme2/fp32.cpp
 	cpu/kernels/softmax/generic/sve2/impl.cpp
 )
diff --git a/src/core/common/Registrars.h b/src/core/common/Registrars.h
index 50b3fc1284..a74316b486 100644
--- a/src/core/common/Registrars.h
+++ b/src/core/common/Registrars.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2020-2023 Arm Limited.
+ * Copyright (c) 2020-2024 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -38,6 +38,12 @@
 #define REGISTER_FP16_SVE2(func_name) nullptr
 #endif /* defined(ARM_COMPUTE_ENABLE_SVE2) */
 
+#if defined(ARM_COMPUTE_ENABLE_SME2)
+#define REGISTER_FP16_SME2(func_name) &(func_name)
+#else /* !defined(ARM_COMPUTE_ENABLE_SME2) */
+#define REGISTER_FP16_SME2(func_name) nullptr
+#endif /* defined(ARM_COMPUTE_ENABLE_SME2) */
+
 #if defined(ARM_COMPUTE_ENABLE_NEON)
 #define REGISTER_FP16_NEON(func_name) &(func_name)
 #else /* !defined(ARM_COMPUTE_ENABLE_NEON) */
@@ -48,6 +54,7 @@
 #define REGISTER_FP16_NEON(func_name) nullptr
 #define REGISTER_FP16_SVE(func_name)  nullptr
 #define REGISTER_FP16_SVE2(func_name) nullptr
+#define REGISTER_FP16_SME2(func_name) nullptr
 #endif /* defined(__ARM_FEATURE_FP16_VECTOR_ARITHMETIC) && defined(ENABLE_FP16_KERNELS) */
 
 #if defined(ENABLE_FP32_KERNELS)
@@ -64,6 +71,12 @@
 #define REGISTER_FP32_SVE2(func_name) nullptr
 #endif /* defined(ARM_COMPUTE_ENABLE_SVE2) */
 
+#if defined(ARM_COMPUTE_ENABLE_SME2)
+#define REGISTER_FP32_SME2(func_name) &(func_name)
+#else /* !defined(ARM_COMPUTE_ENABLE_SME2) */
+#define REGISTER_FP32_SME2(func_name) nullptr
+#endif /* defined(ARM_COMPUTE_ENABLE_SME2) */
+
 #if defined(ARM_COMPUTE_ENABLE_NEON)
 #define REGISTER_FP32_NEON(func_name) &(func_name)
 #else /* !defined(ARM_COMPUTE_ENABLE_NEON) */
@@ -74,6 +87,7 @@
 #define REGISTER_FP32_NEON(func_name) nullptr
 #define REGISTER_FP32_SVE(func_name)  nullptr
 #define REGISTER_FP32_SVE2(func_name) nullptr
+#define REGISTER_FP32_SME2(func_name) nullptr
 #endif /* defined(ENABLE_FP32_KERNELS) */
 
 #if defined(ENABLE_QASYMM8_SIGNED_KERNELS)
diff --git a/src/cpu/kernels/CpuKernelSelectionTypes.h b/src/cpu/kernels/CpuKernelSelectionTypes.h
index 45ebeec394..d71789cc39 100644
--- a/src/cpu/kernels/CpuKernelSelectionTypes.h
+++ b/src/cpu/kernels/CpuKernelSelectionTypes.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2021-2023 Arm Limited.
+ * Copyright (c) 2021-2024 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -104,6 +104,7 @@ struct SoftmaxKernelDataTypeISASelectorData
     DataType            dt;
     cpuinfo::CpuIsaInfo isa;
     bool                is_log;
+    int                 axis;
 };
 
 // Selector pointer types
diff --git a/src/cpu/kernels/CpuSoftmaxKernel.cpp b/src/cpu/kernels/CpuSoftmaxKernel.cpp
index a088fb6660..5cf81f815c 100644
--- a/src/cpu/kernels/CpuSoftmaxKernel.cpp
+++ b/src/cpu/kernels/CpuSoftmaxKernel.cpp
@@ -50,15 +50,17 @@ namespace
 {
 /* Softmax */
 static const std::vector<typename CpuSoftmaxKernel::SoftmaxKernel> available_kernels = {
-#ifdef ARM_COMPUTE_ENABLE_SME2
     {"sme2_fp32_softmax",
      [](const SoftmaxKernelDataTypeISASelectorData &data)
-     { return (!data.is_log && data.dt == DataType::F32 && data.isa.sme2); },
-     REGISTER_FP32_NEON(sme2_fp32_softmax)},
-#endif // ARM_COMPUTE_ENABLE_SME2
+     { return (!data.is_log && data.dt == DataType::F32 && data.isa.sme2 && data.axis == 0); },
+     REGISTER_FP32_SME2(sme2_fp32_softmax)},
     {"neon_fp32_softmax",
      [](const SoftmaxKernelDataTypeISASelectorData &data) { return (!data.is_log && data.dt == DataType::F32); },
      REGISTER_FP32_NEON(neon_fp32_softmax<false>)},
+    {"sme2_fp16_softmax",
+     [](const SoftmaxKernelDataTypeISASelectorData &data)
+     { return (!data.is_log && data.dt == DataType::F16 && data.isa.sme2 && data.axis == 0); },
+     REGISTER_FP16_SME2(sme2_fp16_softmax)},
     {"neon_fp16_softmax",
      [](const SoftmaxKernelDataTypeISASelectorData &data)
      { return (!data.is_log && data.dt == DataType::F16) && data.isa.fp16; },
@@ -156,7 +158,7 @@ void CpuSoftmaxKernel::configure(
     }
 
     const auto *uk = CpuSoftmaxKernel::get_implementation(
-        SoftmaxKernelDataTypeISASelectorData{src->data_type(), CPUInfo::get().get_isa(), is_log});
+        SoftmaxKernelDataTypeISASelectorData{src->data_type(), CPUInfo::get().get_isa(), is_log, axis});
     ARM_COMPUTE_ERROR_ON(uk == nullptr || uk->ukernel == nullptr);
 
     std::string kernel_name = is_log ? std::string("CpuLogSoftmaxKernel") : std::string("CpuSoftmaxKernel");
diff --git a/src/cpu/kernels/softmax/generic/sme2/fp16.cpp b/src/cpu/kernels/softmax/generic/sme2/fp16.cpp
new file mode 100644
index 0000000000..bcd34d1ca2
--- /dev/null
+++ b/src/cpu/kernels/softmax/generic/sme2/fp16.cpp
@@ -0,0 +1,774 @@
+/*
+ * Copyright (c) 2024 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.
+ */
+
+#ifdef ARM_COMPUTE_ENABLE_SME2
+
+#include "arm_compute/core/ITensor.h"
+#include "arm_compute/core/Window.h"
+
+namespace arm_compute
+{
+namespace cpu
+{
+
+// SoftMax
+//
+// Steps:
+//   * Find max:   max_value = max(src)
+//   * Regularize: dst[i] = exp(src[i] - max_value)
+//                 sum_value = sum(dst)
+//   * Normalize:  dst[i] = dst[i] / sum_value
+void sme2_f16_softmax_kernel( //
+    const float16_t *src,
+    float16_t       *dst,
+    float            beta,
+    const uintptr_t  shape[4],
+    const uintptr_t  src_strides[4],
+    const uintptr_t  dst_strides[4])
+{
+    __asm__ volatile(
+        R"(
+            .inst 0xd503477f  // smstart
+
+            // Registers
+            //
+            //   *  x9: temporary, index
+            //   * x10: temporary, -inf
+            //   * x11: temporary, 0
+            //   * x12: temporary, 1.0f
+            //   * x13: temporary, body_length
+            //
+            //   * x20: index_3
+            //   * x21: src_3
+            //   * x22: dst_3
+            //   * x23: index_2
+            //   * x24: src_2
+            //   * x25: dst_2
+            //   * x26: index_1
+            //   * x27: src_1
+            //   * x28: dst_1
+            //
+            //   *  z0: c1
+            //   *  z1: c2
+            //   *  z2: c3
+            //   *  z3: c4
+            //   *  z4: c5
+            //   *  z5: shift
+            //   *  z6: inv_ln2
+            //   *  z7: neg_ln2_hi
+            //   *  z8: neg_ln2_lo
+            //   *  z9: min_input
+            //   * z10: 23, 0
+            //   * z11: max_value
+            //   * z12-z15: x, x_fp32_lower_halves, r_hi, r, r2
+            //   * z16-z19: max_value, shift, z, scale, poly
+            //   * z20-z21: n, p1, p12345
+            //   * z22-z23: n, p23, p2345
+            //   * z24-z25: p45
+            //   * z26: beta
+            //   * z28-z31: sum_value, x_fp32_upper_halves
+            //
+            //   * za0-za3: sum_value
+            //
+            //   * p0: all-true
+            //   * p1: left-over predicate for find-max & normalize loops
+            //   * p2-p4: left-over predicates for regularize loop
+            //   * p4-p7: underflow in vector loop
+            //   * p5-p6: underflow in leftover loop
+            //   *
+            //   * pn9: all-true
+
+            // Prepares all constant values
+
+            ptrue p0.b
+            .inst 0x25207811  // ptrue pn9.b
+
+            mov  w9, #0xfff6  // c1: 0x1.ffffecp-1f = 0x3f7ffff6
+            mov w10, #0xfedb  // c2: 0x1.fffdb6p-2f = 0x3efffedb
+            mov w11, #0xaf33  // c3: 0x1.555e66p-3f = 0x3e2aaf33
+            mov w12, #0x9f17  // c4: 0x1.573e2ep-5f = 0x3d2b9f17
+            mov w13, #0x2010  // c5: 0x1.0e4020p-7f = 0x3c072010
+
+            movk  w9, #0x3f7f, LSL #16  // c1: 0x1.ffffecp-1f = 0x3f7ffff6
+            movk w10, #0x3eff, LSL #16  // c2: 0x1.fffdb6p-2f = 0x3efffedb
+            movk x11, #0x3e2a, LSL #16  // c3: 0x1.555e66p-3f = 0x3e2aaf33
+            movk w12, #0x3d2b, LSL #16  // c4: 0x1.573e2ep-5f = 0x3d2b9f17
+            movk w13, #0x3c07, LSL #16  // c5: 0x1.0e4020p-7f = 0x3c072010
+
+            dup z0.s, w9   // c1.
+            dup z1.s, w10  // c2.
+            dup z2.s, w11  // c3.
+            dup z3.s, w12  // c4.
+            dup z4.s, w13  // c5.
+
+            mov  w9, #0x007f  // shift: 2^23 + 127 = 0x1.0000fep23f = 0x4b00007f
+            mov w10, #0xaa3b  // inv_ln2: 1 / ln(2) = 0x1.715476p+0f = 0x3fb8aa3b
+            mov w11, #0x7200  // neg_ln2_hi: -ln(2) from bits  -1 to -19 = -0x1.62e400p-1f = 0xbf317200
+            mov w12, #0xbe8e  // neg_ln2_lo: -ln(2) from bits -20 to -42 = -0x1.7f7d1cp-20f = 0xb5bfbe8e
+            mov w13, #0x47ae  // min_input (Approximately ln 2^-125): -86.64 = 0xc2ad47ae
+
+            movk  w9, #0x4b00, LSL #16  // shift: 2^23 + 127 = 0x1.0000fep23f = 0x4b00007f
+            movk w10, #0x3fb8, LSL #16  // inv_ln2: 1 / ln(2) = 0x1.715476p+0f = 0x3fb8aa3b
+            movk w11, #0xbf31, LSL #16  // neg_ln2_hi: -ln(2) from bits  -1 to -19 = -0x1.62e400p-1f = 0xbf317200
+            movk w12, #0xb5bf, LSL #16  // neg_ln2_lo: -ln(2) from bits -20 to -42 = -0x1.7f7d1cp-20f = 0xb5bfbe8e
+            movk w13, #0xc2ad, LSL #16  // min_input (Approximately ln 2^-125): -86.64 = 0xc2ad47ae
+
+            dup z5.s, w9   // shift
+            dup z6.s, w10  // inv_ln2
+            dup z7.s, w11  // neg_ln2_hi
+            dup z8.s, w12  // neg_ln2_lo
+            dup z9.s, w13  // min_input
+
+            dup z26.s, %w[beta]  // beta
+            fcvt h26, s26
+            dup z26.h, z26.h[0]
+
+            mov w10, #0xfc00  // -inf: 0xfc00 for fp16
+
+            mov w11, #0  // 0
+
+            // ---------------------------------------------------------------- x13: body_length = (length / vl) * vl
+            cnth x13, ALL, MUL #4
+            udiv x9, %x[length], x13
+            mul x13, x13, x9
+
+            // ==================================================
+            // 3D loop opening
+            // ==================================================
+
+            mov x20, %x[shape_3]
+            mov x21, %x[src]
+            mov x22, %x[dst]
+
+loop_3_start%=:
+            // for index_3 in shape_3 downto 1
+            cmp x20, #0
+            b.eq loop_3_end%=
+            sub x20, x20, #1
+
+            mov x23, %x[shape_2]
+            mov x24, x21
+            mov x25, x22
+
+loop_2_start%=:
+            // for index_2 in shape_2 downto 1
+            cmp x23, #0
+            b.eq loop_2_end%=
+            sub x23, x23, #1
+
+            mov x26, %x[shape_1]
+            mov x27, x24
+            mov x28, x25
+
+loop_1_start%=:
+            // for index_1 in shape_2 downto 1
+            cmp x26, #0
+            b.eq loop_1_end%=
+            sub x26, x26, #1
+
+            // ==================================================
+            // Step 1: Find max
+            // ==================================================
+
+            // ---------------------------------------------------------------- z16-z19: max_value = -inf
+            dup z16.h, w10
+            dup z17.h, w10
+            dup z18.h, w10
+            dup z19.h, w10
+
+            // Loop for processing 4 vectors per iteration.
+            mov x9, #0                                                         // x9: index
+            dup z11.h, w10                                                     // z11: max_value = -inf
+
+find_max_body_start%=:
+            cmp x9, x13
+            b.eq find_max_body_end%=
+
+            .inst 0xa009a76c  // ld1h {z12.h-z15.h}, pn9/z, [x27, x9, LSL #1]      // z12-z15: x
+            .inst 0xc16cb910  // fmax {z16.h-z19.h}, {z16.h-z19.h}, {z12.h-z15.h}  // z16-z19: max_value = max(max_value, x)
+
+            inch x9, ALL, MUL #4
+            b find_max_body_start%=
+find_max_body_end%=:
+
+            // Loop for processing the leftover part.
+find_max_leftover_start%=:
+            whilelo p1.h, x9, %x[length]
+            b.none find_max_leftover_end%=
+
+            ld1h z12.h, p1/z, [x27, x9, LSL #1]                                // z12: x
+            fmax z16.h, p1/m, z16.h, z12.h                                     // z16: max_value = max(max_value, x)
+
+            inch x9
+            b find_max_leftover_start%=
+find_max_leftover_end%=:
+
+            // ---------------------------------------------------------------- z16: max_value
+            .inst 0xc172b110  // fmax {z16.h-z17.h}, {z16.h-z17.h}, {z18.s-z19.h}
+            fmax z16.h, p0/m, z16.h, z17.h
+            fmaxv h16, p0, z16.h
+
+            // ---------------------------------------------------------------- z11: max_value
+            dup z11.h, z16.h[0]
+
+            // ==================================================
+            // Step 2: Regularize, i.e. Calculate exp(x - max(x)
+            // ==================================================
+
+            .inst 0xc00800ff  // zero {za0.s, za1.s, za2.s, za3.s}              za0-za3: sum_value (in fp32)
+
+            // Loop for processing 4 vectors per iteration.
+            mov x9, #0  // ---------------------------------------------------- x9: index
+
+regularize_body_start%=:
+            cmp x9, x13
+            b.eq regularize_body_end%=
+
+            // Loads the input data to 4 consecutive registers ---------------- z12-z15: input_data
+            .inst 0xa009a76c  // ld1h {z12.h-z15.h}, pn9/z, [x27, x9, LSL #1]      // z12-z15: x
+
+            // ---------------------------------------------------------------- z12-z15: x = input_data - max_value
+            fsub z12.h, z12.h, z11.h
+            fsub z13.h, z13.h, z11.h
+            fsub z14.h, z14.h, z11.h
+            fsub z15.h, z15.h, z11.h
+
+            // ---------------------------------------------------------------- z12-z15: x = (input_data - max_value) * beta
+            fmul z12.h, z12.h, z26.h
+            fmul z13.h, z13.h, z26.h
+            fmul z14.h, z14.h, z26.h
+            fmul z15.h, z15.h, z26.h
+
+            // ----------------------------------------------------------------
+            // Convert fp16 values to fp32. This results in four more registers.
+            // z12 --> z12, z28
+            fcvtlt z28.s, p0/m, z12.h
+            fcvt z12.s, p0/m, z12.h
+
+            // z13 --> z13, z29
+            fcvtlt z29.s, p0/m, z13.h
+            fcvt z13.s, p0/m, z13.h
+
+            // z14 --> z14, z30
+            fcvtlt z30.s, p0/m, z14.h
+            fcvt z14.s, p0/m, z14.h
+
+            // z15 --> z15, z31
+            fcvtlt z31.s, p0/m, z15.h
+            fcvt z15.s, p0/m, z15.h
+
+            // ----------------------------------------------------------------
+            //                         Process z12-z15
+            // ----------------------------------------------------------------
+            // ---------------------------------------------------------------- z16-z19: shift
+            mov z16.d, z5.d
+            mov z17.d, z5.d
+            mov z18.d, z5.d
+            mov z19.d, z5.d
+
+            // ---------------------------------------------------------------- p4-p7: underflow = x < min_input
+            fcmlt p4.s, p0/z, z12.s, z9.s
+            fcmlt p5.s, p0/z, z13.s, z9.s
+            fcmlt p6.s, p0/z, z14.s, z9.s
+            fcmlt p7.s, p0/z, z15.s, z9.s
+
+            // ---------------------------------------------------------------- z16-z19: z = shift + x * inv_ln2
+            fmla z16.s, p0/m, z12.s, z6.s
+            fmla z17.s, p0/m, z13.s, z6.s
+            fmla z18.s, p0/m, z14.s, z6.s
+            fmla z19.s, p0/m, z15.s, z6.s
+
+            // ---------------------------------------------------------------- z20-z23: n = z - shift
+            fsub z20.s, z16.s, z5.s
+            fsub z21.s, z17.s, z5.s
+            fsub z22.s, z18.s, z5.s
+            fsub z23.s, z19.s, z5.s
+
+            // ---------------------------------------------------------------- z12-z15: r_hi = x + n * neg_ln2_hi
+            fmla z12.s, p0/m, z20.s, z7.s
+            fmla z13.s, p0/m, z21.s, z7.s
+            fmla z14.s, p0/m, z22.s, z7.s
+            fmla z15.s, p0/m, z23.s, z7.s
+
+            // ---------------------------------------------------------------- z12-z15: r = r_hi + n * neg_ln2_lo
+            fmla z12.s, p0/m, z20.s, z8.s
+            fmla z13.s, p0/m, z21.s, z8.s
+            fmla z14.s, p0/m, z22.s, z8.s
+            fmla z15.s, p0/m, z23.s, z8.s
+
+            // ---------------------------------------------------------------- z16-z19: scale = z << 23 (2^n)
+            dup z10.s, #23
+            urshl z16.s, p0/m, z16.s, z10.s
+            urshl z17.s, p0/m, z17.s, z10.s
+            urshl z18.s, p0/m, z18.s, z10.s
+            urshl z19.s, p0/m, z19.s, z10.s
+
+            // Processes the first 2 vectors. (z12-z13)
+
+            // ---------------------------------------------------------------- z20-z21: p1 = r * c1
+            fmul z20.s, z12.s, z0.s
+            fmul z21.s, z13.s, z0.s
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2
+            mov z22.d, z1.d
+            mov z23.d, z1.d
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2 + r * c3
+            fmla z22.s, p0/m, z12.s, z2.s
+            fmla z23.s, p0/m, z13.s, z2.s
+
+            // ---------------------------------------------------------------- z24-z35: c4
+            mov z24.d, z3.d
+            mov z25.d, z3.d
+
+            // ---------------------------------------------------------------- z24-z25: p45 = c4 + r * c5
+            fmla z24.s, p0/m, z12.s, z4.s
+            fmla z25.s, p0/m, z13.s, z4.s
+
+            // ---------------------------------------------------------------- z12-z13: r2 = r * r
+            fmul z12.s, z12.s, z12.s
+            fmul z13.s, z13.s, z13.s
+
+            // ---------------------------------------------------------------- z22-z23: p2345 = p23 + r2 * p45
+            fmla z22.s, p0/m, z12.s, z24.s
+            fmla z23.s, p0/m, z13.s, z25.s
+
+            // ---------------------------------------------------------------- z20-z21: p12345 = p1 + r2 * p2345
+            fmla z20.s, p0/m, z12.s, z22.s
+            fmla z21.s, p0/m, z13.s, z23.s
+
+            // ---------------------------------------------------------------- z16-z17: poly = scale + p12345 * scale
+            fmla z16.s, p0/m, z20.s, z16.s
+            fmla z17.s, p0/m, z21.s, z17.s
+
+            // Processes the last 2 vectors (z14-z15)
+
+            // ---------------------------------------------------------------- z20-z21: p1 = r * c1
+            fmul z20.s, z14.s, z0.s
+            fmul z21.s, z15.s, z0.s
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2
+            mov z22.d, z1.d
+            mov z23.d, z1.d
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2 + r * c3
+            fmla z22.s, p0/m, z14.s, z2.s
+            fmla z23.s, p0/m, z15.s, z2.s
+
+            // ---------------------------------------------------------------- z24-z35: c4
+            mov z24.d, z3.d
+            mov z25.d, z3.d
+
+            // ---------------------------------------------------------------- z24-z25: p45 = c4 + r * c5
+            fmla z24.s, p0/m, z14.s, z4.s
+            fmla z25.s, p0/m, z15.s, z4.s
+
+            // ---------------------------------------------------------------- z14-z15: r2 = r * r
+            fmul z14.s, z14.s, z14.s
+            fmul z15.s, z15.s, z15.s
+
+            // ---------------------------------------------------------------- z22-z23: p2345 = p23 + r2 * p45
+            fmla z22.s, p0/m, z14.s, z24.s
+            fmla z23.s, p0/m, z15.s, z25.s
+
+            // ---------------------------------------------------------------- z20-z21: p12345 = p1 + r2 * p2345
+            fmla z20.s, p0/m, z14.s, z22.s
+            fmla z21.s, p0/m, z15.s, z23.s
+
+            // ---------------------------------------------------------------- z18-z19: poly = scale + p12345 * scale
+            fmla z18.s, p0/m, z20.s, z18.s
+            fmla z19.s, p0/m, z21.s, z19.s
+
+            // ---------------------------------------------------------------- z16-z19: poly = underflow ? 0 : poly
+            dup z10.s, #0
+            sel z12.s, p4, z10.s, z16.s
+            sel z13.s, p5, z10.s, z17.s
+            sel z14.s, p6, z10.s, z18.s
+            sel z15.s, p7, z10.s, z19.s
+
+            // ---------------------------------------------------------------- sum in fp32
+            .inst 0xc1a17d80  // fadd za.s[w11, #0, VGx4], {z12.s-z15.s}        za0-za3: sum_value = sum_value + poly
+
+            // ----------------------------------------------------------------
+            //                         Process z28-z31
+            // ----------------------------------------------------------------
+            // ---------------------------------------------------------------- z16-z19: shift
+            mov z16.d, z5.d
+            mov z17.d, z5.d
+            mov z18.d, z5.d
+            mov z19.d, z5.d
+
+            // ---------------------------------------------------------------- p4-p7: underflow = x < min_input
+            fcmlt p4.s, p0/z, z28.s, z9.s
+            fcmlt p5.s, p0/z, z29.s, z9.s
+            fcmlt p6.s, p0/z, z30.s, z9.s
+            fcmlt p7.s, p0/z, z31.s, z9.s
+
+            // ---------------------------------------------------------------- z16-z19: z = shift + x * inv_ln2
+            fmla z16.s, p0/m, z28.s, z6.s
+            fmla z17.s, p0/m, z29.s, z6.s
+            fmla z18.s, p0/m, z30.s, z6.s
+            fmla z19.s, p0/m, z31.s, z6.s
+
+            // ---------------------------------------------------------------- z20-z23: n = z - shift
+            fsub z20.s, z16.s, z5.s
+            fsub z21.s, z17.s, z5.s
+            fsub z22.s, z18.s, z5.s
+            fsub z23.s, z19.s, z5.s
+
+            // ---------------------------------------------------------------- z24-z27: r_hi = x + n * neg_ln2_hi
+            fmla z28.s, p0/m, z20.s, z7.s
+            fmla z29.s, p0/m, z21.s, z7.s
+            fmla z30.s, p0/m, z22.s, z7.s
+            fmla z31.s, p0/m, z23.s, z7.s
+
+            // ---------------------------------------------------------------- z27-z30: r = r_hi + n * neg_ln2_lo
+            fmla z28.s, p0/m, z20.s, z8.s
+            fmla z29.s, p0/m, z21.s, z8.s
+            fmla z30.s, p0/m, z22.s, z8.s
+            fmla z31.s, p0/m, z23.s, z8.s
+
+            // ---------------------------------------------------------------- z16-z19: scale = z << 23 (2^n)
+            dup z10.s, #23
+            urshl z16.s, p0/m, z16.s, z10.s
+            urshl z17.s, p0/m, z17.s, z10.s
+            urshl z18.s, p0/m, z18.s, z10.s
+            urshl z19.s, p0/m, z19.s, z10.s
+
+            // Processes the first 2 vectors. (z28-z29)
+
+            // ---------------------------------------------------------------- z20-z21: p1 = r * c1
+            fmul z20.s, z28.s, z0.s
+            fmul z21.s, z29.s, z0.s
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2
+            mov z22.d, z1.d
+            mov z23.d, z1.d
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2 + r * c3
+            fmla z22.s, p0/m, z28.s, z2.s
+            fmla z23.s, p0/m, z29.s, z2.s
+
+            // ---------------------------------------------------------------- z24-z25: c4
+            mov z24.d, z3.d
+            mov z25.d, z3.d
+
+            // ---------------------------------------------------------------- z24-z25: p45 = c4 + r * c5
+            fmla z24.s, p0/m, z28.s, z4.s
+            fmla z25.s, p0/m, z29.s, z4.s
+
+            // ---------------------------------------------------------------- z28-z29: r2 = r * r
+            fmul z28.s, z28.s, z28.s
+            fmul z29.s, z29.s, z29.s
+
+            // ---------------------------------------------------------------- z22-z23: p2345 = p23 + r2 * p45
+            fmla z22.s, p0/m, z28.s, z24.s
+            fmla z23.s, p0/m, z29.s, z25.s
+
+            // ---------------------------------------------------------------- z20-z21: p12345 = p1 + r2 * p2345
+            fmla z20.s, p0/m, z28.s, z22.s
+            fmla z21.s, p0/m, z29.s, z23.s
+
+            // ---------------------------------------------------------------- z16-z17: poly = scale + p12345 * scale
+            fmla z16.s, p0/m, z20.s, z16.s
+            fmla z17.s, p0/m, z21.s, z17.s
+
+            // Processes the last 2 vectors (z30-z31)
+
+            // ---------------------------------------------------------------- z20-z21: p1 = r * c1
+            fmul z20.s, z30.s, z0.s
+            fmul z21.s, z31.s, z0.s
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2
+            mov z22.d, z1.d
+            mov z23.d, z1.d
+
+            // ---------------------------------------------------------------- z22-z23: p23 = c2 + r * c3
+            fmla z22.s, p0/m, z30.s, z2.s
+            fmla z23.s, p0/m, z31.s, z2.s
+
+            // ---------------------------------------------------------------- z24-z35: c4
+            mov z24.d, z3.d
+            mov z25.d, z3.d
+
+            // ---------------------------------------------------------------- z24-z25: p45 = c4 + r * c5
+            fmla z24.s, p0/m, z30.s, z4.s
+            fmla z25.s, p0/m, z31.s, z4.s
+
+            // ---------------------------------------------------------------- z30-z31: r2 = r * r
+            fmul z30.s, z30.s, z30.s
+            fmul z31.s, z31.s, z31.s
+
+            // ---------------------------------------------------------------- z22-z23: p2345 = p23 + r2 * p45
+            fmla z22.s, p0/m, z30.s, z24.s
+            fmla z23.s, p0/m, z31.s, z25.s
+
+            // ---------------------------------------------------------------- z20-z21: p12345 = p1 + r2 * p2345
+            fmla z20.s, p0/m, z30.s, z22.s
+            fmla z21.s, p0/m, z31.s, z23.s
+
+            // ---------------------------------------------------------------- z18-z19: poly = scale + p12345 * scale
+            fmla z18.s, p0/m, z20.s, z18.s
+            fmla z19.s, p0/m, z21.s, z19.s
+
+            // ---------------------------------------------------------------- z16-z19: poly = underflow ? 0 : poly
+            dup z10.s, #0
+            sel z28.s, p4, z10.s, z16.s
+            sel z29.s, p5, z10.s, z17.s
+            sel z30.s, p6, z10.s, z18.s
+            sel z31.s, p7, z10.s, z19.s
+
+            // ---------------------------------------------------------------- sum in fp32
+            .inst 0xc1a17f80  // fadd za.s[w11, #0, VGx4], {z28.s-z31.s}        za0-za3: sum_value = sum_value + poly
+
+            fcvt z12.h, p0/m, z12.s
+            fcvtnt z12.h, p0/m, z28.s
+
+            fcvt z13.h, p0/m, z13.s
+            fcvtnt z13.h, p0/m, z29.s
+
+            fcvt z14.h, p0/m, z14.s
+            fcvtnt z14.h, p0/m, z30.s
+
+            fcvt z15.h, p0/m, z15.s
+            fcvtnt z15.h, p0/m, z31.s
+
+            // Stores 4 consecutive registers to the output
+            .inst 0xa029a78c  // st1h {z12.h-z15.h}, pn9, [x28, x9, LSL #1]
+
+            inch x9, ALL, MUL #4
+            b regularize_body_start%=
+regularize_body_end%=:
+
+            // ---------------------------------------------------------------- z28: sum_value
+            .inst 0xc0066c1c  // mova {z28.s-z31.s}, za.s[w11, #0, VGx4]
+            fadd z28.s, z28.s, z29.s
+            fadd z30.s, z30.s, z31.s
+            fadd z28.s, z28.s, z30.s
+
+            // Loop for processing the leftover part.
+regularize_leftover_start%=:
+            whilelo p2.h, x9, %x[length]
+            b.none regularize_leftover_end%=
+
+            ld1h z12.h, p2/z, [x27, x9, LSL #1]                                // x12: input_data
+
+            fsub z12.h, z12.h, z11.h                                           // z12: x = input_data - max_value
+            fmul z12.h, z12.h, z26.h                                           // z12: x = (input_data - max_value) * beta
+
+            // ---------------------------------------------------------------- z12.h --> z12.s, z13.s
+            fcvtlt z13.s, p2/m, z12.h
+            fcvt z12.s, p2/m, z12.h
+
+            // ---------------------------------------------------------------- p3, p4: predicates for z12, z14
+            pfalse p1.b
+            trn1 p3.h, p2.h, p1.h       // for z12
+            trn2 p4.h, p2.h, p1.h       // for z13
+
+            mov z16.d, z5.d                                                    // z16: shift
+            mov z17.d, z5.d                                                    // z17: shift
+            fcmlt p5.s, p3/z, z12.s, z9.s                                      // p5: underflow = x < min_input
+            fcmlt p6.s, p4/z, z13.s, z9.s                                      // p6: underflow = x < min_input
+            fmla z16.s, p3/m, z12.s, z6.s                                      // z16: z = shift + x * inv_ln2
+            fmla z17.s, p4/m, z13.s, z6.s                                      // z17: z = shift + x * inv_ln2
+            fsub z20.s, z16.s, z5.s                                            // z20: n = z - shift
+            fsub z21.s, z17.s, z5.s                                            // z21: n = z - shift
+            fmla z12.s, p3/m, z20.s, z7.s                                      // z12: r_hi = x + n * neg_ln2_hi
+            fmla z13.s, p4/m, z21.s, z7.s                                      // z13: r_hi = x + n * neg_ln2_hi
+            fmla z12.s, p3/m, z20.s, z8.s                                      // z12: r = r_hi + n * neg_ln2_lo
+            fmla z13.s, p4/m, z21.s, z8.s                                      // z13: r = r_hi + n * neg_ln2_lo
+            dup z10.s, #23                                                     // z10: 23
+            urshl z16.s, p3/m, z16.s, z10.s                                    // z16: scale = z << 23 (2^n)
+            urshl z17.s, p4/m, z17.s, z10.s                                    // z17: scale = z << 23 (2^n)
+            fmul z20.s, z12.s, z0.s                                            // z20: p1 = r * c1
+            fmul z21.s, z13.s, z0.s                                            // z21: p1 = r * c1
+            mov z22.d, z1.d                                                    // z22: p23 = c2
+            mov z23.d, z1.d                                                    // z23: p23 = c2
+            fmla z22.s, p3/m, z12.s, z2.s                                      // z22: p23 = c2 + r * c3
+            fmla z23.s, p4/m, z13.s, z2.s                                      // z23: p23 = c2 + r * c3
+            mov z24.d, z3.d                                                    // z24: c4
+            mov z25.d, z3.d                                                    // z25: c4
+            fmla z24.s, p3/m, z12.s, z4.s                                      // z24: p45 = c4 + r * c5
+            fmla z25.s, p4/m, z13.s, z4.s                                      // z25: p45 = c4 + r * c5
+            fmul z12.s, z12.s, z12.s                                           // z12: r2 = r * r
+            fmul z13.s, z13.s, z13.s                                           // z13: r2 = r * r
+            fmla z22.s, p3/m, z12.s, z24.s                                     // z22: p2345 = p23 + r2 * p45
+            fmla z23.s, p4/m, z13.s, z25.s                                     // z23: p2345 = p23 + r2 * p45
+            fmla z20.s, p3/m, z12.s, z22.s                                     // z20: p12345 = p1 + r2 * p2345
+            fmla z21.s, p4/m, z13.s, z23.s                                     // z21: p12345 = p1 + r2 * p2345
+            fmla z16.s, p3/m, z20.s, z16.s                                     // z16: poly = scale + p12345 * scale
+            fmla z17.s, p4/m, z21.s, z17.s                                     // z17: poly = scale + p12345 * scale
+            dup z10.s, #0                                                      // z10: 0
+            sel z16.s, p5, z10.s, z16.s                                        // z16: poly = underflow ? 0 : poly
+            sel z17.s, p6, z10.s, z17.s                                        // z17: poly = underflow ? 0 : poly
+            fadd z28.s, p3/m, z28.s, z16.s                                     // z28: sum_value = sum_value + poly
+            fadd z28.s, p4/m, z28.s, z17.s                                     // z28: sum_value = sum_value + poly
+
+            fcvt z16.h, p3/m, z16.s
+            fcvtnt z16.h, p4/m, z17.s
+            st1h z16.h, p2, [x28, x9, LSL #1]
+
+            inch x9
+            b regularize_leftover_start%=
+regularize_leftover_end%=:
+
+            // ==================================================
+            // Step 3: Normalize
+            // ==================================================
+
+            // ---------------------------------------------------------------- z28: inv_sum_value = 1 / sum_value
+            faddv s28, p0, z28.s
+            fmov s29, #1.0  // 1.0f
+            fdiv s28, s29, s28
+            fcvt h28, s28
+
+            dup z28.h, z28.h[0]
+
+            // Loop for processing 4 vectors per iteration.
+            mov x9, #0                                                         // x9: index
+
+normalize_body_start%=:
+            cmp x9, x13
+            b.eq normalize_body_end%=
+
+            .inst 0xa009a78c  // ld1h {z12.h-z15.h}, pn9/z, [x28, x9, LSL #1]
+
+            // ---------------------------------------------------------------- z12-z15: result = x * inv_sum_value
+            fmul z12.h, z12.h, z28.h
+            fmul z13.h, z13.h, z28.h
+            fmul z14.h, z14.h, z28.h
+            fmul z15.h, z15.h, z28.h
+
+            .inst 0xa029a78c  // st1h {z12.h-z15.h}, pn9, [x28, x9, LSL #1]
+
+            inch x9, ALL, MUL #4
+            b normalize_body_start%=
+normalize_body_end%=:
+
+            // Loop for processing the leftover part.
+normalize_leftover_start%=:
+            whilelo p1.h, x9, %x[length]
+            b.none normalize_leftover_end%=
+
+            ld1h z12.h, p1/z, [x28, x9, LSL #1]                                // z12: x
+            fmul z12.h, z12.h, z28.h                                           // z12: result = x * inv_sum_value
+
+            st1h z12.h, p1, [x28, x9, LSL #1]
+
+            inch x9
+            b normalize_leftover_start%=
+normalize_leftover_end%=:
+
+            // ==================================================
+            // 3D loop closing
+            // ==================================================
+
+            add x27, x27, %x[src_stride_1]
+            add x28, x28, %x[dst_stride_1]
+            b loop_1_start%=
+loop_1_end%=:
+
+            add x24, x24, %x[src_stride_2]
+            add x25, x25, %x[dst_stride_2]
+            b loop_2_start%=
+loop_2_end%=:
+
+            add x21, x21, %x[src_stride_3]
+            add x22, x22, %x[dst_stride_3]
+            b loop_3_start%=
+loop_3_end%=:
+
+            .inst 0xd503467f  // smstop
+        )"
+        :
+        : [src] "r"(src), [dst] "r"(dst), [beta] "r"(beta),                          //
+          [shape_1] "r"(shape[1]), [shape_2] "r"(shape[2]), [shape_3] "r"(shape[3]), //
+          [src_stride_1] "r"(src_strides[1]), [src_stride_2] "r"(src_strides[2]),
+          [src_stride_3] "r"(src_strides[3]), //
+          [dst_stride_1] "r"(dst_strides[1]), [dst_stride_2] "r"(dst_strides[2]),
+          [dst_stride_3] "r"(dst_strides[3]),                            //
+          [length] "r"(shape[0])                                         //
+        : "cc", "memory",                                                //
+          "p0", "p1", "p2", "p3", "p4", "p5", "p6", "p7", "p9",          //
+          "x9", "x10", "x11", "x12", "x13", "x14",                       //
+          "x20", "x21", "x22", "x23", "x24", "x25", "x26", "x27", "x28", //
+          "z0", "z1", "z2", "z3", "z4", "z5", "z6", "z7",                //
+          "z8", "z9", "z10", "z11", "z12", "z13", "z14", "z15",          //
+          "z16", "z17", "z18", "z19", "z20", "z21", "z22", "z23",        //
+          "z24", "z25", "z26", "z27", "z28", "z29", "z30", "z31"         //
+    );
+}
+
+void sme2_fp16_softmax(const ITensor *in, void *const, ITensor *out, const float beta, int axis, const Window &window)
+{
+    ARM_COMPUTE_UNUSED(axis);
+
+    const auto *src_info = in->info();
+    const auto *dst_info = out->info();
+
+    const auto &full_shape  = dst_info->tensor_shape();
+    const auto &src_strides = src_info->strides_in_bytes();
+    const auto &dst_strides = dst_info->strides_in_bytes();
+
+    const uintptr_t k_shape[] = {
+        full_shape[0],
+        window.num_iterations(1),
+        window.num_iterations(2),
+        window.num_iterations(3),
+    };
+
+    const uintptr_t k_src_strides[] = {
+        src_strides[0],
+        src_strides[1],
+        src_strides[2],
+        src_strides[3],
+    };
+
+    const uintptr_t k_dst_strides[] = {
+        dst_strides[0],
+        dst_strides[1],
+        dst_strides[2],
+        dst_strides[3],
+    };
+
+    const uintptr_t k_src_offset = window[0].start() * src_strides[0] + //
+                                   window[1].start() * src_strides[1] + //
+                                   window[2].start() * src_strides[2] + //
+                                   window[3].start() * src_strides[3];
+
+    const uintptr_t k_dst_offset = window[0].start() * dst_strides[0] + //
+                                   window[1].start() * dst_strides[1] + //
+                                   window[2].start() * dst_strides[2] + //
+                                   window[3].start() * dst_strides[3];
+
+    const auto *k_src = reinterpret_cast<const float16_t *>(in->buffer() + k_src_offset);
+    auto       *k_dst = reinterpret_cast<float16_t *>(out->buffer() + k_dst_offset);
+
+    sme2_f16_softmax_kernel(k_src, k_dst, beta, k_shape, k_src_strides, k_dst_strides);
+}
+
+} // namespace cpu
+} // namespace arm_compute
+
+#endif // ARM_COMPUTE_ENABLE_SME2
diff --git a/src/cpu/kernels/softmax/generic/sme2/fp32.cpp b/src/cpu/kernels/softmax/generic/sme2/fp32.cpp
index e80041c812..159039a320 100644
--- a/src/cpu/kernels/softmax/generic/sme2/fp32.cpp
+++ b/src/cpu/kernels/softmax/generic/sme2/fp32.cpp
@@ -191,16 +191,16 @@ loop_1_start%=:
             // Step 1: Find max
             // ==================================================
 
+            // Loop for processing 4 vectors per iteration.
+            mov x9, #0                                                         // x9: index
+            dup z11.s, w10                                                     // z11: max_value = -inf
+
             // ---------------------------------------------------------------- z16-z19: max_value = -inf
             mov z16.d, z11.d
             mov z17.d, z11.d
             mov z18.d, z11.d
             mov z19.d, z11.d
 
-            // Loop for processing 4 vectors per iteration.
-            mov x9, #0                                                         // x9: index
-            dup z11.s, w10                                                     // z11: max_value = -inf
-
 find_max_body_start%=:
             cmp x9, x13
             b.eq find_max_body_end%=
diff --git a/src/cpu/kernels/softmax/list.h b/src/cpu/kernels/softmax/list.h
index 16fbd31a19..1bb8ed50f0 100644
--- a/src/cpu/kernels/softmax/list.h
+++ b/src/cpu/kernels/softmax/list.h
@@ -42,6 +42,9 @@ DECLARE_SOFTMAX_KERNEL(neon_qasymm8_signed_softmax);
 void sme2_fp32_softmax(
     const ITensor *in, void *const tmp, ITensor *out, const float beta, int axis, const Window &window);
 
+void sme2_fp16_softmax(
+    const ITensor *in, void *const tmp, ITensor *out, const float beta, int axis, const Window &window);
+
 #endif // ARM_COMPUTE_ENABLE_SME2
 
 #undef DECLARE_SOFTMAX_KERNEL
diff --git a/tests/validation/NEON/SoftmaxLayer.cpp b/tests/validation/NEON/SoftmaxLayer.cpp
index 2397d81547..8da5a0d953 100644
--- a/tests/validation/NEON/SoftmaxLayer.cpp
+++ b/tests/validation/NEON/SoftmaxLayer.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2017-2020, 2022-2023 Arm Limited.
+ * Copyright (c) 2017-2020, 2022-2024 Arm Limited.
  *
  * SPDX-License-Identifier: MIT
  *
@@ -122,40 +122,35 @@ template <typename T>
 using NESoftmaxLayerFixture = SoftmaxValidationFixture<Tensor, Accessor, NESoftmaxLayer, T>;
 
 DATA_TEST_CASE(KernelSelection, framework::DatasetMode::ALL,
-    concat(concat(
+    concat(
         combine(
-            make("CpuExt", std::string("NEON")),
+            make("CpuExt", std::string("neon")),
             make("DataType", { DataType::F32,
                             DataType::F16,
                             DataType::QASYMM8,
                             DataType::QASYMM8_SIGNED})
         ),
         combine(
-            make("CpuExt", std::string("SVE")),
+            make("CpuExt", std::string("sme2")),
             make("DataType", { DataType::F32,
                             DataType::F16}))
         ),
-        combine(
-            make("CpuExt", std::string("SVE2")),
-            make("DataType", { DataType::QASYMM8,
-                            DataType::QASYMM8_SIGNED}))
-        ),
         cpu_ext, data_type)
 {
     using namespace cpu::kernels;
 
     cpuinfo::CpuIsaInfo cpu_isa{};
-    cpu_isa.neon = (cpu_ext == "NEON");
-    cpu_isa.sve  = (cpu_ext == "SVE");
-    cpu_isa.sve2 = (cpu_ext == "SVE2");
+    cpu_isa.neon = (cpu_ext == "neon");
+    cpu_isa.sme2 = (cpu_ext == "sme2");
     cpu_isa.fp16 = (data_type == DataType::F16);
 
     const auto *selected_impl = CpuSoftmaxKernel::get_implementation(
-        SoftmaxKernelDataTypeISASelectorData{ data_type, cpu_isa, false /* is_log */ }, cpu::KernelSelectionType::Preferred);
+        SoftmaxKernelDataTypeISASelectorData{ data_type, cpu_isa, false /* is_log */, 0 /* axis */},
+        cpu::KernelSelectionType::Preferred);
 
     ARM_COMPUTE_ERROR_ON_NULLPTR(selected_impl);
 
-    std::string expected = "neon_" + cpu_impl_dt(data_type) + "_softmax";
+    std::string expected = cpu_ext + "_" + cpu_impl_dt(data_type) + "_softmax";
     std::string actual   = selected_impl->name;
 
     ARM_COMPUTE_EXPECT_EQUAL(expected, actual, framework::LogLevel::ERRORS);
@@ -164,9 +159,19 @@ DATA_TEST_CASE(KernelSelection, framework::DatasetMode::ALL,
 TEST_SUITE(Float)
 #ifdef __ARM_FEATURE_FP16_VECTOR_ARITHMETIC
 TEST_SUITE(FP16)
+FIXTURE_DATA_TEST_CASE(RunSmall2D, NESoftmaxLayerFixture<half>, framework::DatasetMode::PRECOMMIT,
+    combine(
+        datasets::SoftmaxLayerSmallShapes(),
+        make("DataType", DataType::F16),
+        make("Beta", { 1.0f, 2.0f }),
+        make("Axis", { 0, -1 })))
+{
+    // Validate output
+    validate(Accessor(_target), _reference, tolerance_f16);
+}
 FIXTURE_DATA_TEST_CASE(RunSmall, NESoftmaxLayerFixture<half>, framework::DatasetMode::PRECOMMIT,
     combine(
-        datasets::Small4DShapes(),
+        datasets::SmallShapes(),
         make("DataType", DataType::F16),
         make("Beta", { 1.0f, 2.0f }),
         make("Axis", { 0, 1 })))
@@ -178,7 +183,7 @@ FIXTURE_DATA_TEST_CASE(RunSmall4D, NESoftmaxLayerFixture<half>, framework::Datas
     combine(
         datasets::Small4DShapes(),
         make("DataType", DataType::F16),
-        make("Beta", { 1.0f, 2.0f }),
+        make("Beta", { 1.0f }),
         make("Axis", { 0, 2, -1 })))
 {
     // Validate output