X-Git-Url: https://git.ucc.asn.au/?a=blobdiff_plain;f=Kernel%2Farch%2Fx86%2Finclude%2Farch.h;h=eff85fc2af4363799aab3c158f05f34bd908d24f;hb=de2ae10743172075f2d527780bdfd890ccddb8e7;hp=773556840a9dca2ca272d5fc2884ef3fff67a422;hpb=a506fc15c09f7d8f178a7c7d9658b5bf45778128;p=tpg%2Facess2.git

diff --git a/Kernel/arch/x86/include/arch.h b/Kernel/arch/x86/include/arch.h
index 77355684..eff85fc2 100644
--- a/Kernel/arch/x86/include/arch.h
+++ b/Kernel/arch/x86/include/arch.h
@@ -29,44 +29,71 @@
 
 #define __ASM__	__asm__ __volatile__
 
-// === MACROS ===
-typedef volatile int	tSpinlock;
-#define IS_LOCKED(lockptr)	(!!(*(tSpinlock*)lockptr))
+// === Spinlocks ===
 /**
- * \brief Inter-Process interrupt (does a Yield)
+ * \brief Short Spinlock structure
  */
-#define LOCK(lockptr)	do {\
-	int v=1;\
-	while(v) {\
-		__ASM__("xchgl %%eax, (%%edi)":"=a"(v):"a"(1),"D"(lockptr));\
-		if(v) Threads_Yield();\
-	}\
-}while(0)
+struct sShortSpinlock {
+	volatile int	Lock;	//!< Lock value
+	 int	IF;	//!< Interrupt state on call to SHORTLOCK
+};
 /**
- * \brief Tight spinlock (does a HLT)
+ * \brief Determine if a short spinlock is locked
+ * \param Lock	Lock pointer
  */
-#define TIGHTLOCK(lockptr)	do{\
-	int v=1;\
-	while(v) {\
-		__ASM__("xchgl %%eax,(%%edi)":"=a"(v):"a"(1),"D"(lockptr));\
-		if(v) __ASM__("hlt");\
-	}\
-}while(0)
+static inline int IS_LOCKED(struct sShortSpinlock *Lock) {
+	return !!Lock->Lock;
+}
 /**
- * \brief Very Tight spinlock (short inter-cpu lock)
+ * \brief Acquire a Short Spinlock
+ * \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.
  */
-#define VTIGHTLOCK(lockptr)	do{\
-	int v=1;\
-	while(v)__ASM__("xchgl %%eax,(%%edi)":"=a"(v):"a"(1),"D"(lockptr));\
-}while(0)
+static inline void SHORTLOCK(struct sShortSpinlock *Lock) {
+	 int	v = 1;
+	 int	IF;
+	// int	cpu = GetCPUNum() + 1;
+	
+	// Save interrupt state and clear interrupts
+	__ASM__ ("pushf;\n\tcli;\n\tpop %%eax" : "=a"(IF));
+	IF &= 0x200;
+	
+	// Wait for another CPU to release
+	while(v)
+		__ASM__("xchgl %%eax, (%%edi)":"=a"(v):"a"(1),"D"(&Lock->Lock));
+	
+	Lock->IF = IF;
+}
 /**
- * \brief Release a held spinlock
+ * \brief Release a short lock
+ * \param Lock	Lock pointer
  */
-#define	RELEASE(lockptr)	__ASM__("lock andl $0, (%%edi)"::"D"(lockptr));
+static inline void SHORTREL(struct sShortSpinlock *Lock) {
+	// Lock->IF can change anytime once Lock->Lock is zeroed
+	if(Lock->IF) {
+		Lock->Lock = 0;
+		__ASM__ ("sti");
+	}
+	else {
+		Lock->Lock = 0;
+	}
+}
+
+// === 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 ===
 typedef unsigned int	Uint;	// Unsigned machine native integer