adds an idt

kernel/arch/idt/idt.c

@@ -0,0 +1,43 @@
+#include <stdbool.h>
+
+#include <kernel/x86/idt.h>
+
+__attribute__((aligned(0x10)))
+static idt_entry_t idt[256];
+
+static idtr_t idtr;
+
+static bool vectors[IDT_MAX_DESCRIPTORS];
+
+void exception_handler()
+{
+	__asm__ volatile ("cli; hlt"); // hangs the computer
+}
+
+void idt_set_descriptor(uint8_t vector, void *isr, uint8_t flags)
+{
+	idt_entry_t* descriptor = &idt[vector];
+
+	descriptor->isr_low = (uint32_t) isr & 0xFFFF;
+	descriptor->kernel_cs = 0x08; // this is whatever the kernel code selector is in the GDT
+	descriptor->attributes = flags;
+	descriptor->isr_high = (uint32_t) isr >> 16;
+	descriptor->reserved = 0;
+}
+
+
+extern void* isr_stub_table[];
+void idt_init(void)
+{
+	idtr.base = (uintptr_t)&idt[0];
+	idtr.limit = (uint16_t) sizeof(idt_entry_t) * IDT_MAX_DESCRIPTORS - 1;
+
+	for (uint8_t vector = 0; vector < 32; vector++) {
+		idt_set_descriptor(vector, isr_stub_table[vector], 0x8E);
+		vectors[vector] = true;
+	}
+
+	__asm__ volatile("lidt %0" : : "m"(idtr)); // load the new IDT
+	__asm__ volatile("sti"); // set the interrupt flag
+}
+