new OS

kernel/idt.c

@@ -0,0 +1,43 @@
+#include "idt.h"
+#include "io.h"
+
+#define KERNEL_CS 0x08  // Kernel code segment selector
+
+idt_entry_t idt[IDT_ENTRIES];
+idt_ptr_t idt_ptr;
+
+// External assembly stubs for ISRs (provided below)
+extern void isr0();
+extern void isr13();
+extern void isr_default();
+
+// Helper to set an IDT gate
+void idt_set_gate(int n, uint32_t handler) {
+    idt[n].offset_low = handler & 0xFFFF;
+    idt[n].selector = KERNEL_CS;
+    idt[n].zero = 0;
+    idt[n].type_attr = 0x8E;  // Present, ring 0, 32-bit interrupt gate
+    idt[n].offset_high = (handler >> 16) & 0xFFFF;
+}
+
+// Load IDT via lidt
+static void idt_load() {
+    asm volatile("lidt (%0)" : : "r" (&idt_ptr));
+}
+
+// IDT initialization
+void idt_init() {
+    idt_ptr.limit = sizeof(idt_entry_t) * IDT_ENTRIES - 1;
+    idt_ptr.base = (uint32_t)&idt;
+
+    // Clear all entries
+    for (int i = 0; i < IDT_ENTRIES; i++) {
+        idt_set_gate(i, (uint32_t)isr_default);
+    }
+
+    // Set specific handlers
+    idt_set_gate(0, (uint32_t)isr0);   // Divide by zero
+    idt_set_gate(13, (uint32_t)isr13); // General protection fault
+
+    idt_load();
+}