feat(idt): add idt_entry, idt and idt_r structs

k/idt.h

@@ -0,0 +1,35 @@
+#ifndef IDT_H
+#define IDT_H
+
+#include <stdint.h>
+
+#define IDT_NB_ENTRIES 32
+#define IDT_SIZE (IDT_NB_ENTRIES * sizeof(struct idt_entry))
+
+struct idt_entry
+{
+    uint16_t offset_1   : 16;
+    uint16_t selector   : 16;
+
+    uint8_t zero        : 8;    // unused, set to 0
+    uint8_t type        : 3;    // gate type
+    uint8_t size        : 1;
+    uint8_t zero_2      : 1;    // set to 0 for interrupt and trap gates
+    uint8_t desc_priv   : 2;    // Descriptor privilege
+    uint8_t present     : 1;
+
+    uint16_t offset_2   : 16;
+} __attribute__ ((packed));
+
+struct idt
+{
+    struct idt_entry entries[IDT_NB_ENTRIES];
+};
+
+struct idt_r
+{
+    uint16_t limit;
+    uint32_t addr;
+} __attribute__ ((packed));
+
+#endif  /* !IDT_H */