arch: i386: fix IDT exception handler

Fix the i386's general exception handler to actually work. Fix provided
by Jon Sanderson (jjs295356@gmail.com).

Signed-off-by: Danny Holman <dholman@gymli.xyz>

1 files changed, 35 insertions, 0 deletions

diff --git a/arch/i386/include/kernel/idt.h b/arch/i386/include/kernel/idt.h
new file mode 100644
index 0000000..7ccad30
--- /dev/null
+++ b/arch/i386/include/kernel/idt.h
@@ -0,0 +1,35 @@
+#ifndef I386_IDT_H
+#define I386_IDT_H
+
+#include <stdint.h>
+
+// IDT Flags
+#define SEGMENT_PRESENT 0x8
+#define SEGMENT_RING0   0x0
+#define SEGMENT_STORAGE 0x0
+#define SEGMENT_GATE    0xE
+#define SEGMENT_DPL     0x8
+
+#define SEGMENT_FLAG    SEGMENT_PRESENT | SEGMENT_RING0 | SEGMENT_STORAGE |\
+                        SEGMENT_GATE    | SEGMENT_DPL;
+
+struct idt_entry {
+        uint16_t        isr_low;
+        uint16_t        kernel_cs;
+        uint8_t         reserved;
+        uint8_t         flags;
+        uint16_t        isr_high;
+} __attribute__((packed));
+
+struct idt_ptr {
+        uint16_t        limit;
+        uint32_t        base;
+} __attribute__((packed));
+
+extern struct idt_entry idt[256];
+extern struct idt_ptr idtr;
+
+extern void idt_set_gate(uint8_t num, void(*handler)(void), uint16_t cs, uint8_t flags);
+extern void exception_handler(int num);
+
+#endif
\ No newline at end of file