Update irq.c

Implement the irq handles

kernel/irq.c

@@ -1,5 +1,56 @@
 #include "irq.h"
+#include "io.h"
+#include "isr.h"
 
-void irq_init() {
-    // IRQ initialization code
+#define PIC1_CMD   0x20
+#define PIC1_DATA  0x21
+#define PIC2_CMD   0xA0
+#define PIC2_DATA  0xA1
+
+void irq_remap(void)
+{
+    outb(PIC1_CMD, 0x11);   // ICW1 – edge triggered, cascade, need ICW4
+    outb(PIC2_CMD, 0x11);
+
+    outb(PIC1_DATA, 0x20);  // ICW2 – master base vector
+    outb(PIC2_DATA, 0x28);  // ICW2 – slave base vector
+
+    outb(PIC1_DATA, 0x04);  // ICW3 – slave on IRQ2
+    outb(PIC2_DATA, 0x02);  // ICW3 – cascade identity
+
+    outb(PIC1_DATA, 0x01);  // ICW4 – 8086 mode
+    outb(PIC2_DATA, 0x01);
+
+    // Mask everything except IRQ0 (timer) and IRQ1 (keyboard) for now
+    outb(PIC1_DATA, 0b11111001);
+    outb(PIC2_DATA, 0xFF);
+}
+
+void irq_install(void)
+{
+    irq_remap();
+
+    /* Fill IRQ entries in the IDT (0x20 … 0x2F) */
+    extern void irq0(), irq1(), irq2(), irq3(), irq4(), irq5(), irq6(), irq7();
+    extern void irq8(), irq9(), irq10(), irq11(), irq12(), irq13(), irq14(), irq15();
+
+    idt_set_gate(0x20, (uint32_t)irq0);
+    idt_set_gate(0x21, (uint32_t)irq1);
+    /* … repeat for the rest or loop … */
+    for (int i = 2; i < 16; ++i)
+        idt_set_gate(0x20 + i, (uint32_t)irq0 + i * 8); // crude but works
+}
+
+/* Called from the assembly stubs (see irq.asm below) */
+void irq_handler(uint32_t int_num)
+{
+    /* int_num is the *remapped* vector, e.g. 0x21 for keyboard */
+    if (interrupt_handlers[int_num]) {
+        interrupt_handlers[int_num]();
+    }
+
+    /* ---- EOI ---- */
+    if (int_num >= 0x28)          // slave PIC
+        outb(PIC2_CMD, 0x20);
+    outb(PIC1_CMD, 0x20);         // always master
 }