Implement Default for TSS.

- Some documentation.

README.md

@@ -45,3 +45,7 @@ If the condition is (or should be) unreachable, but if not upheld, leading to UB
 ### Be gentle
 
 Don't just write as much code as you can as quick as possible. Take your time and be careful.
+
+### Commits
+
+Use descriptive commits. One way to force yourself to do that is to not pass the `-m` flag, which will make your editor pop up, so that you can conviniently write long commit messages.

src/arch/x86_64/irq.rs

@@ -1,7 +1,9 @@
 //! # IRQ handling
+//!
 //! This module defines IRQ handling functions. These functions should all be #[naked],
 //! unsafe, extern, and end in `iretq`
 
+/// Interupt Request handler.
 #[naked]
 pub unsafe extern fn irq() {
 

src/arch/x86_64/mem.rs

@@ -2,8 +2,7 @@
 ///
 /// Copy N bytes of memory from one location to another.
 #[no_mangle]
-pub unsafe extern fn memcpy(dest: *mut u8, src: *const u8,
+pub unsafe extern fn memcpy(dest: *mut u8, src: *const u8, n: usize) -> *mut u8 {
-                            n: usize) -> *mut u8 {
     let mut i = 0;
     while i < n {
         *dest.offset(i as isize) = *src.offset(i as isize);

src/arch/x86_64/mod.rs

@@ -1,23 +1,25 @@
-/// Global descriptor table
+//! X86_64 architecture primitives.
+
+/// Global descriptor table.
 pub mod gdt;
 
-/// Interrupt descriptor table
+/// Interrupt descriptor table.
 pub mod idt;
 
-/// IO Handling
+/// IO handling.
 pub mod io;
 
-/// IRQ Handling
+/// IRQ handling.
 pub mod irq;
 
-/// Initialization and main function
+/// Initialization and main function.
 pub mod main;
 
-/// Memcpy, memmove, etc.
+/// Core memory routines.
 pub mod mem;
 
-/// Serial driver and print! support
+/// Serial driver and `print!` support.
 pub mod serial;
 
-/// Task state segment
+/// Task state segment.
 pub mod tss;

src/arch/x86_64/tss.rs

@@ -1,20 +1,22 @@
-#[repr(packed)]
+/// The Task State Segment.
+#[repr(C, packed)]
+#[derive(Debug, Default, Clone)]
 pub struct Tss {
-    pub reserved1: u32,
+    /// Reserved.
-    pub sp0: u64,
+    pub _reserved1: u32,
-    pub sp1: u64,
+    /// The stack-pointers (reg RSP) for the IO privilege level 0 through 2.
-    pub sp2: u64,
+    pub rsp: [u64; 3],
-    pub reserved2: u32,
+    /// Reserved.
-    pub reserved3: u32,
+    pub _reserved2: u32,
-    pub ist1: u64,
+    /// Reserved.
-    pub ist2: u64,
+    pub _reserved3: u32,
-    pub ist3: u64,
+    pub ist: [u64; 7],
-    pub ist4: u64,
+    /// Reserved.
-    pub ist5: u64,
+    pub _reserved4: u32,
-    pub ist6: u64,
+    /// Reserved.
-    pub ist7: u64,
+    pub _reserved5: u32,
-    pub reserved4: u32,
+    // Reserved.
-    pub reserved5: u32,
     pub reserved6: u16,
+    /// The offset to the IOPB.
     pub iomap_base: u16,
 }