1 files changed, 46 insertions, 0 deletions
diff --git a/src/arch/x86_64/interrupt/pic_8259.rs b/src/arch/x86_64/interrupt/pic_8259.rs
new file mode 100644
index 0000000..43a102c
--- /dev/null
+++ b/src/arch/x86_64/interrupt/pic_8259.rs
@@ -0,0 +1,46 @@
+// For now, the PIC is stateless, i.e. we don'e need a struct for it.
+// Perhaps I need a Mutex handle later...
+use crate::arch::x86_64::io_port::*;
+
+const IMR1: u16 = 0x21;
+const IMR2: u16 = 0xa1;
+const CTRL1: u16 = 0x20;
+const CTRL2: u16 = 0xa0;
+
+pub struct PicDeviceInt;
+impl PicDeviceInt {
+	pub const TIMER: u8 = 0;
+	pub const KEYBOARD: u8 = 1;
+}
+
+// 8-bit registers IMR1 and IMR2 registers hold interrupt masking bit 0~7 and
+// 8~15; if an interrupt is masked(set 1) on the respective bit, it's disabled
+pub fn allow(interrupt: u8) {
+	if interrupt < 8 {
+		let old = inb(IMR1);
+		outb(IMR1, old & !(1 << interrupt));
+	} else {
+		let old = inb(IMR2);
+		outb(IMR2, old & !(1 << (interrupt - 8)));
+	}
+}
+
+pub fn forbid(interrupt: u8) {
+	if interrupt < 8 {
+		let old = inb(IMR1);
+		outb(IMR1, old | (1 << interrupt));
+	} else {
+		let old = inb(IMR2);
+		outb(IMR2, old | (1 << (interrupt - 8)));
+	}
+}
+
+pub fn is_masked(interrupt: u8) -> bool {
+	if interrupt < 8 {
+		let val = inb(IMR1);
+		return val & (interrupt) != 0;
+	} else {
+		let val = inb(IMR2);
+		return val & (interrupt - 8) != 0;
+	}
+}