From 0b8cd65458a3f816c670c4a3eecdd595b33f0d25 Mon Sep 17 00:00:00 2001
From: greg <greg.shuflin@protonmail.com>
Date: Thu, 18 Jul 2019 10:28:20 -0700
Subject: [PATCH] Handle timer interrupt

---
 src/interrupts.rs | 28 ++++++++++++++++++++++++++++
 src/main.rs       |  6 +++++-
 src/vga_buffer.rs |  5 ++++-
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/src/interrupts.rs b/src/interrupts.rs
index 991207c..5825b09 100644
--- a/src/interrupts.rs
+++ b/src/interrupts.rs
@@ -5,6 +5,22 @@ use pic8259_simple::ChainedPics;
 use spin;
 use crate::gdt;
 
+#[derive(Copy, Clone, Debug)]
+#[repr(u8)]
+pub enum InterruptIndex {
+  Timer = PIC_1_OFFSET,
+}
+
+impl InterruptIndex {
+  fn as_u8(self) -> u8 {
+    self as u8
+  }
+  fn as_usize(self) -> usize {
+    usize::from(self as u8)
+  }
+}
+
+
 const PIC_1_OFFSET: u8 = 32;
 const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
 static PICS: spin::Mutex<ChainedPics> =
@@ -18,10 +34,14 @@ lazy_static! {
     idt.double_fault.set_handler_fn(double_fault_handler)
       .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
     }
+    idt[InterruptIndex::Timer.as_usize()]
+      .set_handler_fn(timer_interrupt_handler);
     idt
   };
 }
 
+
+
 pub fn init_idt() {
   IDT.load();
 }
@@ -30,6 +50,7 @@ pub fn initalize_pics() {
   unsafe {
     PICS.lock().initialize();
   }
+  x86_64::instructions::interrupts::enable();
 }
 
 extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFrame) {
@@ -40,3 +61,10 @@ extern "x86-interrupt" fn breakpoint_handler(stack_frame: &mut InterruptStackFra
 extern "x86-interrupt" fn double_fault_handler(stack_frame: &mut InterruptStackFrame, code: u64) {
   panic!("EXCEPTION - DOUBLE FAULT (code {})\n{:#?}", code, stack_frame);
 }
+
+extern "x86-interrupt" fn timer_interrupt_handler(_stack_frame: &mut InterruptStackFrame) {
+  print!(".");
+  unsafe {
+    PICS.lock().notify_end_of_interrupt(InterruptIndex::Timer.as_u8())
+  }
+}
diff --git a/src/main.rs b/src/main.rs
index 459af83..11f953d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -30,6 +30,10 @@ pub extern "C" fn _start() -> ! {
   for i in 1..10 {
     println!("Gamarjoba, munde: {}", i);
   }
-  loop {}
+  loop {
+    for _ in 0..100_000 {
+    }
+    print!("-");
+  }
 }
 
diff --git a/src/vga_buffer.rs b/src/vga_buffer.rs
index a9224e1..b4f21d6 100644
--- a/src/vga_buffer.rs
+++ b/src/vga_buffer.rs
@@ -18,7 +18,10 @@ macro_rules! println {
 #[doc(hidden)]
 pub fn _print(args: fmt::Arguments) {
     use core::fmt::Write;
-    WRITER.lock().write_fmt(args).unwrap();
+    use x86_64::instructions::interrupts;
+    interrupts::without_interrupts(|| {
+      WRITER.lock().write_fmt(args).unwrap();
+    });
 }
 
 #[allow(dead_code)]