1 files changed, 99 insertions, 0 deletions
diff --git a/include/oaknut/feature_detection/feature_detection_w32.hpp b/include/oaknut/feature_detection/feature_detection_w32.hpp
new file mode 100644
index 00000000..366a2600
--- /dev/null
+++ b/include/oaknut/feature_detection/feature_detection_w32.hpp
@@ -0,0 +1,99 @@
+// SPDX-FileCopyrightText: Copyright (c) 2023 merryhime <https://mary.rs>
+// SPDX-License-Identifier: MIT
+
+#pragma once
+
+#ifndef WIN32_LEAN_AND_MEAN
+#    define WIN32_LEAN_AND_MEAN
+#endif
+
+#include <windows.h>
+
+#include <cstddef>
+#include <cstdint>
+#include <optional>
+
+#include <processthreadsapi.h>
+
+#include "oaknut/feature_detection/cpu_feature.hpp"
+#include "oaknut/feature_detection/id_registers.hpp"
+
+namespace oaknut {
+
+namespace detail {
+
+inline std::optional<std::uint64_t> read_registry_hklm(const std::string& subkey, const std::string& name)
+{
+    std::uint64_t value;
+    DWORD value_len = sizeof(value);
+    if (::RegGetValueA(HKEY_LOCAL_MACHINE, subkey.c_str(), name.c_str(), RRF_RT_REG_QWORD, nullptr, &value, &value_len) == ERROR_SUCCESS) {
+        return value;
+    }
+    return std::nullopt;
+}
+
+inline std::uint64_t read_id_register(std::size_t core_index, const std::string& name)
+{
+    return read_registry_hklm("HARDWARE\\DESCRIPTION\\System\\CentralProcessor\\" + std::to_string(core_index), "CP " + name).value_or(0);
+}
+
+}  // namespace detail
+
+// Ref: https://learn.microsoft.com/en-us/windows/win32/api/processthreadsapi/nf-processthreadsapi-isprocessorfeaturepresent
+
+inline CpuFeatures detect_features_via_IsProcessorFeaturePresent()
+{
+    CpuFeatures result;
+
+    if (::IsProcessorFeaturePresent(30))  // PF_ARM_V8_CRYPTO_INSTRUCTIONS_AVAILABLE
+        result |= CpuFeatures{CpuFeature::AES, CpuFeature::PMULL, CpuFeature::SHA1, CpuFeature::SHA256};
+    if (::IsProcessorFeaturePresent(31))  // PF_ARM_V8_CRC32_INSTRUCTIONS_AVAILABLE
+        result |= CpuFeatures{CpuFeature::CRC32};
+    if (::IsProcessorFeaturePresent(34))  // PF_ARM_V81_ATOMIC_INSTRUCTIONS_AVAILABLE
+        result |= CpuFeatures{CpuFeature::LSE};
+    if (::IsProcessorFeaturePresent(43))  // PF_ARM_V82_DP_INSTRUCTIONS_AVAILABLE
+        result |= CpuFeatures{CpuFeature::DotProd};
+    if (::IsProcessorFeaturePresent(44))  // PF_ARM_V83_JSCVT_INSTRUCTIONS_AVAILABLE
+        result |= CpuFeatures{CpuFeature::JSCVT};
+    if (::IsProcessorFeaturePresent(45))  // PF_ARM_V83_LRCPC_INSTRUCTIONS_AVAILABLE
+        result |= CpuFeatures{CpuFeature::LRCPC};
+
+    return result;
+}
+
+inline CpuFeatures detect_features()
+{
+    CpuFeatures result{CpuFeature::FP, CpuFeature::ASIMD};
+    result |= detect_features_via_IsProcessorFeaturePresent();
+    return result;
+}
+
+inline std::size_t get_core_count()
+{
+    ::SYSTEM_INFO sys_info;
+    ::GetSystemInfo(&sys_info);
+    return sys_info.dwNumberOfProcessors;
+}
+
+inline std::optional<id::IdRegisters> read_id_registers(std::size_t core_index)
+{
+    return id::IdRegisters{
+        detail::read_id_register(core_index, "4000"),
+        id::Pfr0Register{detail::read_id_register(core_index, "4020")},
+        id::Pfr1Register{detail::read_id_register(core_index, "4021")},
+        id::Pfr2Register{detail::read_id_register(core_index, "4022")},
+        id::Zfr0Register{detail::read_id_register(core_index, "4024")},
+        id::Smfr0Register{detail::read_id_register(core_index, "4025")},
+        id::Isar0Register{detail::read_id_register(core_index, "4030")},
+        id::Isar1Register{detail::read_id_register(core_index, "4031")},
+        id::Isar2Register{detail::read_id_register(core_index, "4032")},
+        id::Isar3Register{detail::read_id_register(core_index, "4033")},
+        id::Mmfr0Register{detail::read_id_register(core_index, "4038")},
+        id::Mmfr1Register{detail::read_id_register(core_index, "4039")},
+        id::Mmfr2Register{detail::read_id_register(core_index, "403A")},
+        id::Mmfr3Register{detail::read_id_register(core_index, "403B")},
+        id::Mmfr4Register{detail::read_id_register(core_index, "403C")},
+    };
+}
+
+}  // namespace oaknut