optimize cpu (4h 12m)

src/interrupts.rs

@@ -4,6 +4,7 @@ use lazy_static::lazy_static;
 use crate::gdt;
 use pic8259::ChainedPics;
 use spin;
+use crate::print;
 
 lazy_static! {
     static ref IDT: InterruptDescriptorTable = {
@@ -11,8 +12,10 @@ lazy_static! {
         idt.breakpoint.set_handler_fn(breakpoint_handler);
         unsafe {
             idt.double_fault.set_handler_fn(double_fault_handler)
-                .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX); // new
+                .set_stack_index(gdt::DOUBLE_FAULT_IST_INDEX);
         }
+        idt[InterruptIndex::Timer.as_usize()]
+            .set_handler_fn(timer_interrupt_handler);
 
         idt
     };
@@ -45,3 +48,30 @@ pub const PIC_2_OFFSET: u8 = PIC_1_OFFSET + 8;
 
 pub static PICS: spin::Mutex<ChainedPics> =
     spin::Mutex::new(unsafe {ChainedPics::new(PIC_1_OFFSET, PIC_2_OFFSET) });
+
+#[derive(Debug, Clone, Copy)]
+#[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())
+    }
+}
+
+extern "x86-interrupt" fn timer_interrupt_handler(
+    _stack_frame: InterruptStackFrame)
+{
+    print!(".");
+
+    unsafe {
+        PICS.lock()
+            .notify_end_of_interrupt(InterruptIndex::Timer.as_u8());
+    }
+}

src/lib.rs

@@ -48,7 +48,7 @@ pub fn test_panic_handler(info: &PanicInfo) -> ! {
     serial_println!("[failed]\n");
     serial_println!("Error: {}\n", info);
     exit_qemu(QemuExitCode::Failed);
-    loop {}
+    hlt_loop();
 }
 
 /// Entry point for `cargo test`
@@ -57,7 +57,7 @@ pub fn test_panic_handler(info: &PanicInfo) -> ! {
 pub extern "C" fn _start() -> ! {
     init();
     test_main();
-    loop {}
+    hlt_loop();
 }
 
 #[cfg(test)]
@@ -80,4 +80,10 @@ pub fn exit_qemu(exit_code: QemuExitCode) {
         let mut port = Port::new(0xf4);
         port.write(exit_code as u32);
     }
+}
+
+pub fn hlt_loop() -> ! {
+    loop {
+        x86_64::instructions::hlt();
+    }
 }

src/main.rs

@@ -10,19 +10,13 @@ use donald::println;
 #[no_mangle]
 pub extern "C" fn _start() -> ! {
     println!("Hello World{}", "!");
-    println!("It did not crash!");
     donald::init();
 
-    fn stack_overflow() {
-        stack_overflow();
-    }
-
-    stack_overflow();
-
     #[cfg(test)]
     test_main();
 
-    loop {}
+    println!("It did not crash!");
+    donald::hlt_loop();    
 }
 
 /// This function is called on panic.
@@ -30,7 +24,7 @@ pub extern "C" fn _start() -> ! {
 #[panic_handler]
 fn panic(info: &PanicInfo) -> ! {
     println!("{}", info);
-    loop {}
+    donald::hlt_loop();
 }
 
 #[cfg(test)]

src/serial.rs

@@ -14,7 +14,14 @@ lazy_static! {
 #[doc(hidden)]
 pub fn _print(args: ::core::fmt::Arguments) {
     use core::fmt::Write;
-    SERIAL1.lock().write_fmt(args).expect("Printing to serial failed");
+    use x86_64::instructions::interrupts;       
+
+    interrupts::without_interrupts(|| {         
+        SERIAL1
+            .lock()
+            .write_fmt(args)
+            .expect("Printing to serial failed");
+    });
 }
 
 /// Prints to the host through the serial interface.

src/vga_buffer.rs

@@ -140,7 +140,11 @@ 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();
+    });
 }
 
 #[test_case]
@@ -157,10 +161,16 @@ fn test_println_many() {
 
 #[test_case]
 fn test_println_output() {
+    use core::fmt::Write;
+    use x86_64::instructions::interrupts;
+
     let s = "Some test string that fits on a single line";
-    println!("{}", s);
-    for (i, c) in s.chars().enumerate() {
-        let screen_char = WRITER.lock().buffer.chars[BUFFER_HEIGHT - 2][i].read();
-        assert_eq!(char::from(screen_char.ascii_character), c);
-    }
+    interrupts::without_interrupts(|| {
+        let mut writer = WRITER.lock();
+        writeln!(writer, "\n{}", s).expect("writeln failed");
+        for (i, c) in s.chars().enumerate() {
+            let screen_char = writer.buffer.chars[BUFFER_HEIGHT - 2][i].read();
+            assert_eq!(char::from(screen_char.ascii_character), c);
+        }
+    });
 }