Provide modeling and runtime detection of i8mm arm extension

Some extra thoughts could be done on the way we model instruction set
extensions, I'm not happy with the way it's currently done.

Author: serge-sans-paille

include/xsimd/arch/xsimd_i8mm_neon64.hpp

@@ -0,0 +1,17 @@
+/***************************************************************************
+ * Copyright (c) Johan Mabille, Sylvain Corlay, Wolf Vollprecht and         *
+ * Martin Renou                                                             *
+ * Copyright (c) QuantStack                                                 *
+ * Copyright (c) Serge Guelton                                              *
+ *                                                                          *
+ * Distributed under the terms of the BSD 3-Clause License.                 *
+ *                                                                          *
+ * The full license is in the file LICENSE, distributed with this software. *
+ ****************************************************************************/
+
+#ifndef XSIMD_I8MM_NEON64_HPP
+#define XSIMD_I8MM_NEON64_HPP
+
+#include "../types/xsimd_i8mm_neon64_register.hpp"
+
+#endif

include/xsimd/arch/xsimd_isa.hpp

@@ -104,6 +104,10 @@
 #include "./xsimd_neon64.hpp"
 #endif
 
+#if XSIMD_WITH_I8MM_NEON64
+#include "./xsimd_i8mm_neon64.hpp"
+#endif
+
 #if XSIMD_WITH_SVE
 #include "./xsimd_sve.hpp"
 #endif

include/xsimd/config/xsimd_arch.hpp

@@ -194,7 +194,7 @@ namespace xsimd
 
     using all_sve_architectures = arch_list<detail::sve<512>, detail::sve<256>, detail::sve<128>>;
     using all_rvv_architectures = arch_list<detail::rvv<512>, detail::rvv<256>, detail::rvv<128>>;
-    using all_arm_architectures = typename detail::join<all_sve_architectures, arch_list<neon64, neon>>::type;
+    using all_arm_architectures = typename detail::join<all_sve_architectures, arch_list<i8mm<neon64>, neon64, neon>>::type;
     using all_riscv_architectures = all_rvv_architectures;
     using all_wasm_architectures = arch_list<wasm>;
     using all_architectures = typename detail::join<all_riscv_architectures, all_wasm_architectures, all_arm_architectures, all_x86_architectures>::type;

include/xsimd/config/xsimd_config.hpp

@@ -349,6 +349,17 @@
 #define XSIMD_WITH_NEON64 0
 #endif
 
+/**
+ * @ingroup xsimd_config_macro
+ *
+ * Set to 1 if i8mm neon64 extension is available at compile-time, to 0 otherwise.
+ */
+#if defined(__ARM_FEATURE_MATMUL_INT8)
+#define XSIMD_WITH_I8MM_NEON64 1
+#else
+#define XSIMD_WITH_I8MM_NEON64 0
+#endif
+
 /**
  * @ingroup xsimd_config_macro
  *

include/xsimd/config/xsimd_cpuid.hpp

@@ -18,6 +18,11 @@
 #if defined(__linux__) && (defined(__ARM_NEON) || defined(_M_ARM) || defined(__riscv_vector))
 #include <asm/hwcap.h>
 #include <sys/auxv.h>
+
+#ifndef HWCAP2_I8MM
+#define HWCAP2_I8MM (1 << 13)
+#endif
+
 #endif
 
 #if defined(_MSC_VER)
@@ -66,6 +71,7 @@ namespace xsimd
             ARCH_FIELD_EX(avx512vnni<::xsimd::avx512vbmi>, avx512vnni_vbmi)
             ARCH_FIELD(neon)
             ARCH_FIELD(neon64)
+            ARCH_FIELD_EX(i8mm<::xsimd::neon64>, i8mm_neon64)
             ARCH_FIELD(sve)
             ARCH_FIELD(rvv)
             ARCH_FIELD(wasm)
@@ -83,6 +89,9 @@ namespace xsimd
 #if defined(__aarch64__) || defined(_M_ARM64)
                 neon = 1;
                 neon64 = 1;
+#if defined(__linux__) && (!defined(__ANDROID_API__) || __ANDROID_API__ >= 18)
+                i8mm_neon64 = bool(getauxval(AT_HWCAP2) & HWCAP2_I8MM);
+#endif
 #elif defined(__ARM_NEON) || defined(_M_ARM)
 
 #if defined(__linux__) && (!defined(__ANDROID_API__) || __ANDROID_API__ >= 18)

include/xsimd/types/xsimd_all_registers.hpp

@@ -36,6 +36,8 @@
 #include "xsimd_avx512dq_register.hpp"
 #include "xsimd_avx512f_register.hpp"
 
+#include "xsimd_i8mm_neon64_register.hpp"
+
 #include "xsimd_neon64_register.hpp"
 #include "xsimd_neon_register.hpp"
 

include/xsimd/types/xsimd_i8mm_neon64_register.hpp

@@ -0,0 +1,46 @@
+/***************************************************************************
+ * Copyright (c) Johan Mabille, Sylvain Corlay, Wolf Vollprecht and         *
+ * Martin Renou                                                             *
+ * Copyright (c) QuantStack                                                 *
+ * Copyright (c) Serge Guelton                                              *
+ *                                                                          *
+ * Distributed under the terms of the BSD 3-Clause License.                 *
+ *                                                                          *
+ * The full license is in the file LICENSE, distributed with this software. *
+ ****************************************************************************/
+
+#ifndef XSIMD_I8MM_NEON64_REGISTER_HPP
+#define XSIMD_I8MM_NEON64_REGISTER_HPP
+
+#include "./xsimd_neon64_register.hpp"
+
+namespace xsimd
+{
+    template <typename arch>
+    struct i8mm;
+
+    /**
+     * @ingroup architectures
+     *
+     * Neon64 + i8mm instructions
+     */
+    template <>
+    struct i8mm<neon64> : neon64
+    {
+        static constexpr bool supported() noexcept { return XSIMD_WITH_I8MM_NEON64; }
+        static constexpr bool available() noexcept { return true; }
+        static constexpr unsigned version() noexcept { return generic::version(8, 2, 0); }
+        static constexpr char const* name() noexcept { return "i8mm+neon64"; }
+    };
+
+#if XSIMD_WITH_I8MM_NEON64
+    namespace types
+    {
+
+        XSIMD_DECLARE_SIMD_REGISTER_ALIAS(i8mm<neon64>, neon64);
+
+    }
+#endif
+
+}
+#endif