1 files changed, 109 insertions, 0 deletions
diff --git a/src/kernel/interrupts/irq.c b/src/kernel/interrupts/irq.c
new file mode 100644
index 0000000..cf9e1fe
--- /dev/null
+++ b/src/kernel/interrupts/irq.c
@@ -0,0 +1,109 @@
+#include "../io/io.h"
+#include "interrupts.h"
+#include "../graphics/graphics.h"
+
+extern void irq0();
+
+extern void irq1();
+
+extern void irq2();
+
+extern void irq3();
+
+extern void irq4();
+
+extern void irq5();
+
+extern void irq6();
+
+extern void irq7();
+
+extern void irq8();
+
+extern void irq9();
+
+extern void irq10();
+
+extern void irq11();
+
+extern void irq12();
+
+extern void irq13();
+
+extern void irq14();
+
+extern void irq15();
+
+// Array to handle custom IRQ handlers
+void *irq_routines[16] = {
+        0, 0, 0, 0, 0, 0, 0, 0,
+        0, 0, 0, 0, 0, 0, 0, 0
+};
+
+// Install custom IRQ handler
+void irq_install_handler(int irq, void (*handler)(struct regs *r)) {
+    irq_routines[irq] = handler;
+}
+
+// Removes the custom IRQ handler
+void irq_uninstall_handler(int irq) {
+    irq_routines[irq] = 0;
+}
+
+int irq_is_installed(int irq) {
+    return irq_routines[irq] != 0;
+}
+
+// Remap IRQs for protected mode compatibility via the PIC
+void irq_remap(void) {
+    send(0x20, 0x11);
+    send(0xA0, 0x11);
+    send(0x21, 0x20);
+    send(0xA1, 0x28);
+    send(0x21, 0x04);
+    send(0xA1, 0x02);
+    send(0x21, 0x01);
+    send(0xA1, 0x01);
+    send(0x21, 0x0);
+    send(0xA1, 0x0);
+}
+
+// Map ISRs to the correct entries in the IDT
+void irq_install() {
+    irq_remap();
+    idt_set_gate(32, (unsigned) irq0, 0x08, 0x8E);
+    idt_set_gate(33, (unsigned) irq1, 0x08, 0x8E);
+    idt_set_gate(34, (unsigned) irq2, 0x08, 0x8E);
+    idt_set_gate(35, (unsigned) irq3, 0x08, 0x8E);
+    idt_set_gate(36, (unsigned) irq4, 0x08, 0x8E);
+    idt_set_gate(37, (unsigned) irq5, 0x08, 0x8E);
+    idt_set_gate(38, (unsigned) irq6, 0x08, 0x8E);
+    idt_set_gate(39, (unsigned) irq7, 0x08, 0x8E);
+    idt_set_gate(40, (unsigned) irq8, 0x08, 0x8E);
+    idt_set_gate(41, (unsigned) irq9, 0x08, 0x8E);
+    idt_set_gate(42, (unsigned) irq10, 0x08, 0x8E);
+    idt_set_gate(43, (unsigned) irq11, 0x08, 0x8E);
+    idt_set_gate(44, (unsigned) irq12, 0x08, 0x8E);
+    idt_set_gate(45, (unsigned) irq13, 0x08, 0x8E);
+    idt_set_gate(46, (unsigned) irq14, 0x08, 0x8E);
+    idt_set_gate(47, (unsigned) irq15, 0x08, 0x8E);
+}
+
+// Handle IRQ ISRs
+void irq_handler(struct regs *r) {
+    void (*handler)(struct regs *r);
+
+    // Execute custom handler if exists
+    handler = irq_routines[r->int_no - 32];
+    if (handler) {
+        handler(r);
+    }
+
+    // Send end of interrupt to second (slave) IRQ controller
+    if (r->int_no >= 40) {
+        send(0xA0, 0x20);
+    }
+
+    // Send end of interrupt to master interrupt controller
+    send(0x20, 0x20);
+}