1 files changed, 85 insertions, 0 deletions
diff --git a/kernel/src/interrupt/pic.c b/kernel/src/interrupt/pic.c
new file mode 100644
index 0000000..86056a1
--- /dev/null
+++ b/kernel/src/interrupt/pic.c
@@ -0,0 +1,85 @@
+#include <sys.h>
+#include <print.h>
+
+#include "pic.h"
+
+#define PIC1_COMMAND_PORT 0x20
+#define PIC1_DATA_PORT 0x21
+#define PIC2_COMMAND_PORT 0xA0
+#define PIC2_DATA_PORT 0xA1
+
+void pic_remap(uint8_t offset) {
+
+    debugk("Remapping PIC");
+
+	char a1 = inb(PIC1_DATA_PORT);
+	char a2 = inb(PIC2_DATA_PORT);
+	// control word 1
+	// 0x11: initialize, enable ICW4
+	outb(PIC1_COMMAND_PORT, 0x11);
+	io_wait();
+	outb(PIC2_COMMAND_PORT, 0x11);
+	io_wait();
+	// control word 2
+	// interrupt offset
+	outb(PIC1_DATA_PORT, offset);
+	io_wait();
+	outb(PIC2_DATA_PORT, offset + 8);
+	io_wait();
+	// control word 3
+	// primary pic: set which pin secondary is connected to
+	// (pin 2)
+	outb(PIC1_DATA_PORT, 0x04);
+	io_wait();
+	outb(PIC2_DATA_PORT, 2);
+	io_wait();
+	// control word 3
+	// 0x01: enable 8086 mode
+	outb(PIC1_DATA_PORT, 0x01);
+	io_wait();
+	outb(PIC2_DATA_PORT, 0x01);
+	io_wait();
+	// clear data registers
+	outb(PIC1_DATA_PORT, a1);
+	outb(PIC2_DATA_PORT, a2);
+
+    succek("PIC has been remapped to offset 0x%X", offset);
+}
+
+void pic_mask(int irq) {
+	uint8_t port;
+	if(irq < 8) {
+		port = PIC1_DATA_PORT;
+	} else {
+		irq -= 8;
+		port = PIC2_DATA_PORT;
+	}
+	uint8_t mask = inb(port);
+	outb(port, mask | (1 << irq));
+}
+
+void pic_unmask(int irq) {
+	uint8_t port;
+	if(irq < 8) {
+		port = PIC1_DATA_PORT;
+	} else {
+		irq -= 8;
+		port = PIC2_DATA_PORT;
+	}
+	uint8_t mask = inb(port);
+	outb(port, mask & ~(1 << irq));
+}
+
+void pic_disable(void) {
+	outb(PIC1_DATA_PORT, 0xff);
+	io_wait();
+	outb(PIC2_DATA_PORT, 0xff);
+	io_wait();
+}
+
+void pic_eoi(int irq) {
+	if(irq >= 8) {
+		outb(PIC2_COMMAND_PORT, 0x20);
+	}
+	outb(PIC1_COMMAND_PORT, 0x20);
+}