x86_64: fix flag reading

4 files changed, 92 insertions, 6 deletions

diff --git a/arch/x86_64/CMakeLists.txt b/arch/x86_64/CMakeLists.txt
index 28199f35..59df016e 100644
--- a/arch/x86_64/CMakeLists.txt
+++ b/arch/x86_64/CMakeLists.txt
@@ -26,6 +26,7 @@ target_sources("x86_64" PRIVATE
 
 target_sources("x86_64" PRIVATE
     # CPU Initialization
+    "arch/cpu/flags.cpp"
     "arch/cpu/initialization.cpp"
     "arch/cpu/interrupts.cpp"
     "arch/cpu/interrupts.S"
diff --git a/arch/x86_64/arch/cpu/flags.cpp b/arch/x86_64/arch/cpu/flags.cpp
new file mode 100644
index 00000000..12a2ceee
--- /dev/null
+++ b/arch/x86_64/arch/cpu/flags.cpp
@@ -0,0 +1,16 @@
+#include <arch/cpu/flags.hpp>
+
+namespace arch::cpu
+{
+
+  auto read_flags() noexcept -> flags
+  {
+    auto rflags = flags{};
+    asm volatile("pushfq\n"
+                 "popq %0\n"
+                 : "=r"(rflags));
+
+    return rflags;
+  }
+
+}  // namespace arch::cpu
\ No newline at end of file
diff --git a/arch/x86_64/arch/cpu/flags.hpp b/arch/x86_64/arch/cpu/flags.hpp
new file mode 100644
index 00000000..d19750f4
--- /dev/null
+++ b/arch/x86_64/arch/cpu/flags.hpp
@@ -0,0 +1,72 @@
+#ifndef TEACHOS_ARCH_X86_64_CPU_FLAGS_HPP
+#define TEACHOS_ARCH_X86_64_CPU_FLAGS_HPP
+
+#include <kstd/bitfield_enum.hpp>
+
+#include <cstdint>
+#include <type_traits>
+
+namespace arch::cpu
+{
+
+  enum struct flags : std::uint64_t
+  {
+    carry = 1u << 0,
+    parity = 1u << 2,
+    auxiliary_carry = 1u << 4,
+    zero = 1u << 6,
+    sign = 1u << 7,
+    trap = 1u << 8,
+    interrupt = 1u << 9,
+    direction = 1u << 10,
+    overflow = 1u << 11,
+    io_privilege_level_low = 1u << 12,
+    io_privilege_level_high = 1u << 13,
+    nested_task = 1u << 14,
+    resume = 1u << 16,
+    virtual_8086_mode = 1u << 17,
+    alignment_check = 1u << 18,
+    virtual_interrupt = 1u << 19,
+    virtual_interrupt_pending = 1u << 20,
+    cpuid_available = 1u << 21,
+    aes_key_schedule_loaded = 1u << 30,
+    rex32 = 1u << 31,
+  };
+
+}  // namespace arch::cpu
+
+template<>
+struct kstd::is_bitfield_enum<arch::cpu::flags> : std::true_type
+{
+};
+
+namespace arch::cpu
+{
+
+  //! Read the current CPU flags.
+  //!
+  //! @return The current set of active CPU flags.
+  auto read_flags() noexcept -> flags;
+
+  //! Read a given set of CPU flags.
+  //!
+  //! @return The state of the selected flags.
+  template<flags Flags>
+  auto read_flags() noexcept -> flags
+  {
+    auto flags = read_flags();
+    return flags & Flags;
+  }
+
+  //! Check if a given set of CPU flags is set.
+  //!
+  //! @return @p true iff. all of the selected flags are set, @p false otherwise.
+  template<flags Flags>
+  auto check_flags() noexcept -> bool
+  {
+    return read_flags() == Flags;
+  }
+
+}  // namespace arch::cpu
+
+#endif
\ No newline at end of file
diff --git a/arch/x86_64/kapi/interrupts.cpp b/arch/x86_64/kapi/interrupts.cpp
index 8d863bad..37745122 100644
--- a/arch/x86_64/kapi/interrupts.cpp
+++ b/arch/x86_64/kapi/interrupts.cpp
@@ -1,16 +1,13 @@
 #include <kapi/interrupts.hpp>
 
+#include <arch/cpu/flags.hpp>
+
 namespace kapi::interrupts
 {
 
   auto enabled() -> bool
   {
-    auto value = false;
-    asm volatile("pushfq\n"
-                 "pop %0\n"
-                 "and $0x200, %0"
-                 : "=r"(value));
-    return value;
+    return arch::cpu::check_flags<arch::cpu::flags::interrupt>();
   }
 
   auto enabled(bool value) -> void