Handout

arch/idt.cc

@@ -0,0 +1,35 @@
+#include "idt.h"
+
+#include "core_interrupt.h"
+
+namespace IDT {
+
+// Interrupt Descriptor Table, 8 Byte aligned
+constinit struct InterruptDescriptor idt[256] = {};
+
+// Struct used for loading (the address of) the Interrupt Descriptor Table into
+// the IDT-Register
+struct Register {
+  uint16_t limit;  // Address of the last valid byte (relative to base)
+  struct InterruptDescriptor* base;
+  explicit Register(uint8_t max = 255) {
+    limit = (max + static_cast<uint16_t>(1)) * sizeof(InterruptDescriptor) - 1;
+    base = idt;
+  }
+} __attribute__((packed));
+
+static_assert(sizeof(InterruptDescriptor) == 16,
+              "IDT::InterruptDescriptor has wrong size");
+static_assert(sizeof(Register) == 10, "IDT::Register has wrong size");
+static_assert(alignof(decltype(idt)) % 8 == 0, "IDT must be 8 byte aligned!");
+
+void load() {
+  // Create structure required for writing to idtr and load via lidt
+  Register idtr(Core::Interrupt::VECTORS - 1);
+  asm volatile("lidt %0\n\t" ::"m"(idtr));
+}
+
+void set(Core::Interrupt::Vector vector, InterruptDescriptor descriptor) {
+  idt[(uint8_t)vector] = descriptor;
+}
+}  // namespace IDT