From 18d7dbb9279850e8deb8636107dbcea73a4d2846 Mon Sep 17 00:00:00 2001
From: Eryn Wells <eryn@erynwells.me>
Date: Sun, 13 Mar 2016 04:44:22 -0400
Subject: [PATCH] Implement hardware interrupt enable/disable

---
 src/PIC.cc | 46 ++++++++++++++++++++++++++++++++++++++++++++++
 src/PIC.hh |  5 +++++
 2 files changed, 51 insertions(+)

diff --git a/src/PIC.cc b/src/PIC.cc
index e958b16..76d84ea 100644
--- a/src/PIC.cc
+++ b/src/PIC.cc
@@ -164,4 +164,50 @@ PIC::endOfInterrupt(uint8_t irq)
     kernel::io::outb(PIC1.command, OCW2::NOPEOI);
 }
 
+
+void
+PIC::enableInterrupt(uint8_t irq,
+                     bool enabled)
+{
+    if (enabled) {
+        enableIRQ(irq);
+    } else {
+        disableIRQ(irq);
+    }
+}
+
+/*
+ * Private
+ */
+
+inline uint16_t
+PIC::portForIRQ(uint8_t irq)
+{
+    return irq < 8 ? PIC1.data : PIC2.data;
+}
+
+
+void
+PIC::enableIRQ(uint8_t irq)
+{
+    uint16_t port = portForIRQ(irq);
+    if (irq >= 8) {
+        irq -= 8;
+    }
+    uint8_t value = kernel::io::inb(port) & ~(1 << irq);
+    kernel::io::outb(port, value);
+}
+
+
+void
+PIC::disableIRQ(uint8_t irq)
+{
+    uint16_t port = portForIRQ(irq);
+    if (irq >= 8) {
+        irq -= 8;
+    }
+    uint8_t value = kernel::io::inb(port) | (1 << irq);
+    kernel::io::outb(port, value);
+}
+
 } /* namespace x86 */
diff --git a/src/PIC.hh b/src/PIC.hh
index aebad34..26cd581 100644
--- a/src/PIC.hh
+++ b/src/PIC.hh
@@ -48,6 +48,11 @@ struct PIC
      * the PIC's IMR register. If the bit is set, the IRQ is ignored.
      */
     void enableInterrupt(uint8_t irq, bool enabled);
+
+private:
+    uint16_t portForIRQ(uint8_t irq);
+    void enableIRQ(uint8_t irq);
+    void disableIRQ(uint8_t irq);
 };
 
 } /* namespace x86 */