1 files changed, 54 insertions, 0 deletions
diff --git a/kern/inc/interrupt.h b/kern/inc/interrupt.h
index 7c15ccd..f90ee04 100644
--- a/kern/inc/interrupt.h
+++ b/kern/inc/interrupt.h
@@ -9,6 +9,10 @@
 #ifndef _INTERRUPT_H_
 #define _INTERRUPT_H_
 
+#include <x86/seg.h>
+
+#include <paging.h>
+
 /**
  * IRQ # of timer
  */
@@ -20,6 +24,56 @@
 #define KBD_IRQ 1
 
 /**
+ * @brief an idt entry
+ */
+typedef struct idt_s {
+    unsigned long lo;
+    unsigned long hi;
+} idt_t;
+
+/** means this entry requires ring 0 privilige */
+#define IDT_DPL_KERNEL 0
+/** means this entry requires ring 3 privilige */
+#define IDT_DPL_USER 3
+/** means this entry is valid */
+#define IDT_P 1
+/** means this entry is a 32 bit interrupt */
+#define IDT_TYPE_I32 0xe
+/** means this entry is a 32 bit trap */
+#define IDT_TYPE_T32 0xf
+
+/** P bit's position */
+#define IDT_P_SHIFT (47 - 32)
+/** DPL's position */
+#define IDT_DPL_SHIFT (45 - 32)
+/** TYPE's position */
+#define IDT_TYPE_SHIFT (40 - 32)
+/** CS's position */
+#define IDT_CS_SHIFT 16
+
+/** EIP's high part's bits */
+#define IDT_EIP_HI_MASK 0xffff0000
+/** EIP's low part's bits */
+#define IDT_EIP_LO_MASK 0x0000ffff
+
+#define IDT_FAULT_15 15
+
+/**
+ * @brief create an idt entry
+ * @param eip eip
+ * @param type type
+ * @param dpl dpl
+ * @return the idt entry
+ */
+static inline idt_t make_idt(va_t eip, int type, int dpl) {
+    idt_t idt;
+    idt.hi = ((eip & IDT_EIP_HI_MASK) | (IDT_P << IDT_P_SHIFT) |
+              (dpl << IDT_DPL_SHIFT) | (type << IDT_TYPE_SHIFT));
+    idt.lo = ((SEGSEL_KERNEL_CS << IDT_CS_SHIFT) | (eip & IDT_EIP_LO_MASK));
+    return idt;
+}
+
+/**
  * @brief initialize idt
  */
 void idt_init();