From 2ae2035466cfa7816079a067ccee25e2b8bac6bc Mon Sep 17 00:00:00 2001
From: John Hodge <tpg@mutabah.net>
Date: Sun, 22 Aug 2010 10:37:46 +0800
Subject: [PATCH] Fixing commenting (always nice)

---
 Kernel/arch/x86/include/arch.h | 36 ++++++++++++++++++++++++++--------
 Kernel/threads.c               | 16 +++++++++++++--
 2 files changed, 42 insertions(+), 10 deletions(-)

diff --git a/Kernel/arch/x86/include/arch.h b/Kernel/arch/x86/include/arch.h
index 67a62901..ede3bf05 100644
--- a/Kernel/arch/x86/include/arch.h
+++ b/Kernel/arch/x86/include/arch.h
@@ -29,47 +29,67 @@
 
 #define __ASM__	__asm__ __volatile__
 
-#define LONGLOCK_NUM_THREADS	8
-
-// === MACROS ===
+// === Spinlocks ===
+/**
+ * \brief Short Spinlock structure
+ */
 struct sShortSpinlock {
-	volatile int	Lock;
-	 int	IF;
+	volatile int	Lock;	//!< Lock value
+	 int	IF;	//!< Interrupt state on call to SHORTLOCK
 };
 /**
  * \brief Determine if a short spinlock is locked
+ * \param Lock	Lock pointer
  */
 static inline int IS_LOCKED(struct sShortSpinlock *Lock) {
 	return !!Lock->Lock;
 }
 /**
  * \brief Acquire a Short Spinlock
- * \note Stops interrupts, so be careful
+ * \param Lock	Lock pointer
+ * 
+ * This type of mutex should only be used for very short sections of code,
+ * or in places where a Mutex_* would be overkill, such as appending
+ * an element to linked list (usually two assignement lines in C)
+ * 
+ * \note This type of lock halts interrupts, so ensure that no timing
+ * functions are called while it is held.
  */
 static inline void SHORTLOCK(struct sShortSpinlock *Lock) {
 	 int	v = 1;
+	
+	// Save interrupt state
 	__ASM__ ("pushf;\n\tpop %%eax" : "=a"(Lock->IF));
 	Lock->IF &= 0x200;
-	__ASM__ ("cli");	// Stop task switches
+	
+	// Stop interrupts
+	__ASM__ ("cli");
+	
 	// Wait for another CPU to release
 	while(v)
 		__ASM__("xchgl %%eax, (%%edi)":"=a"(v):"a"(1),"D"(&Lock->Lock));
 }
 /**
  * \brief Release a short lock
+ * \param Lock	Lock pointer
  */
 static inline void SHORTREL(struct sShortSpinlock *Lock) {
 	Lock->Lock = 0;
-	#if 0
+	#if 0	// Which is faster?, meh the test is simpler
 	__ASM__ ("pushf;\n\tor %0, (%%esp);\n\tpopf" : : "a"(Lock->IF));
 	#else
 	if(Lock->IF)	__ASM__ ("sti");
 	#endif
 }
+
+// === MACROS ===
 /**
  * \brief Halt the CPU
  */
 #define	HALT()	__asm__ __volatile__ ("hlt")
+/**
+ * \brief Fire a magic breakpoint (bochs)
+ */
 #define	MAGIC_BREAK()	__asm__ __volatile__ ("xchg %bx, %bx")
 
 // === TYPES ===
diff --git a/Kernel/threads.c b/Kernel/threads.c
index 8ec0e9fc..99a9add6 100644
--- a/Kernel/threads.c
+++ b/Kernel/threads.c
@@ -840,7 +840,14 @@ void Threads_SegFault(tVAddr Addr)
 }
 
 /**
- * \brief heavy mutex
+ * \brief Acquire a heavy mutex
+ * \param Mutex	Mutex to acquire
+ * 
+ * This type of mutex checks if the mutex is avaliable, and acquires it
+ * if it is. Otherwise, the current thread is added to the mutex's wait
+ * queue and the thread suspends. When the holder of the mutex completes,
+ * the oldest thread (top thread) on the queue is given the lock and
+ * restarted.
  */
 void Mutex_Acquire(tMutex *Mutex)
 {
@@ -884,7 +891,8 @@ void Mutex_Acquire(tMutex *Mutex)
 }
 
 /**
- * \brief Release a held spinlock
+ * \brief Release a held mutex
+ * \param Mutex	Mutex to release
  */
 void Mutex_Release(tMutex *Mutex)
 {
@@ -904,6 +912,10 @@ void Mutex_Release(tMutex *Mutex)
 	SHORTREL( &Mutex->Protector );
 }
 
+/**
+ * \brief Is this mutex locked?
+ * \param Mutex	Mutex pointer
+ */
 int Mutex_IsLocked(tMutex *Mutex)
 {
 	return Mutex->Owner != NULL;
-- 
2.20.1