Move to ring 3

src/kernel/idt.h

@@ -0,0 +1,41 @@
+#pragma once
+
+#include <stdint.h>
+
+struct __attribute__((packed)) idt_gate_descriptor {
+    uint16_t offset_0;
+    uint16_t segment_selector;
+    uint8_t ist;
+
+    /* `flags`
+       =======
+       bit 0-3: gate type
+       bit   4: unused
+       bit 5-6: dpl
+       bit   7: present bit
+      
+       DPL is ignored by hardware interupts and present bit must be 1 */
+    uint8_t flags;
+
+    uint16_t offset_1;
+};
+
+enum idt_flags : uint8_t {
+    IDT_GATE_TYPE_TASK_GATE        = 0x5,
+    IDT_GATE_TYPE_INTERUPT_GATE_16 = 0x6,
+    IDT_GATE_TYPE_TRAP_GATE_16     = 0x7,
+    IDT_GATE_TYPE_INTERUPT_GATE_32 = 0xE,
+    IDT_GATE_TYPE_TRAP_GATE_32     = 0xF,
+    
+    IDT_DPL_0 = 0 << 5,
+    IDT_DPL_1 = 1 << 5,
+    IDT_DPL_2 = 2 << 5,
+    IDT_DPL_3 = 3 << 5,
+
+    IDT_PRESENT = 1 << 7,
+};
+
+struct idt_gate_descriptor idt_encode_descriptor(uint32_t offset, uint16_t segment_selector, uint8_t ist, enum idt_flags type);
+
+void idt_load(struct idt_gate_descriptor table[], uint16_t size);
+