Split gdt.* from interrupts.*

src/kernel/gdt.h

@@ -0,0 +1,27 @@
+#pragma once
+/// \file gdt.h
+/// Definitions relating to system descriptor tables: GDT, IDT, TSS
+#include <stdint.h>
+#include "kutil/memory.h"
+
+/// Set up the GDT and TSS, and switch segment registers to point
+/// to them.
+void gdt_init();
+
+/// Set an entry in the IDT
+/// \arg i         Index in the IDT (vector of the interrupt this handles)
+/// \arg addr      Address of the handler
+/// \arg selector  GDT selector to set when invoking this handler
+/// \arg flags     Descriptor flags to set
+void idt_set_entry(uint8_t i, uint64_t addr, uint16_t selector, uint8_t flags);
+
+/// Set the stack pointer for a given ring in the TSS
+/// \arg ring  Ring to set for (0-2)
+/// \arg rsp   Stack pointer to set
+void tss_set_stack(int ring, addr_t rsp);
+
+/// Dump information about the current GDT to the screen
+void gdt_dump();
+
+/// Dump information about the current IDT to the screen
+void idt_dump();