remove unnecessary comments introduced by tools from MdePkg. The regular express...

[mirror_edk2.git] / MdePkg / Library / BaseLib / SynchronizationGcc.c

diff --git a/MdePkg/Library/BaseLib/SynchronizationGcc.c b/MdePkg/Library/BaseLib/SynchronizationGcc.c
index 40b1e4a36b303fb83b3c3785118d4c42a8c7db1e..0786c12a5992d0d2b5e51df56267e0d06c4e7dd0 100644 (file)
--- a/MdePkg/Library/BaseLib/SynchronizationGcc.c
+++ b/MdePkg/Library/BaseLib/SynchronizationGcc.c
@@ -10,10 +10,11 @@
   THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,\r
   WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.\r
 \r
-  Module Name:  SynchronizationGcc.c\r
-\r
 **/\r
 \r
+\r
+\r
+\r
 #include "BaseLibInternals.h"\r
 \r
 //\r
@@ -46,7 +47,6 @@ GetSpinLockProperties (
   VOID\r
   )\r
 {\r
-  // @bug May use a PCD entry to determine this alignment.\r
   return 32;\r
 }\r
 \r
@@ -63,7 +63,7 @@ GetSpinLockProperties (
   @param  SpinLock  A pointer to the spin lock to initialize to the released\r
                     state.\r
 \r
-  @return SpinLock\r
+  @return SpinLock in release state.\r
 \r
 **/\r
 SPIN_LOCK *\r
@@ -98,7 +98,7 @@ InitializeSpinLock (
 \r
   @param  SpinLock  A pointer to the spin lock to place in the acquired state.\r
 \r
-  @return SpinLock\r
+  @return SpinLock accquired lock.\r
 \r
 **/\r
 SPIN_LOCK *\r
@@ -107,15 +107,32 @@ AcquireSpinLock (
   IN OUT  SPIN_LOCK                 *SpinLock\r
   )\r
 {\r
-  UINT64                            Tick;\r
-  UINT64                            Start, End;\r
-  UINT64                            Timeout;\r
+  UINT64  Current;\r
+  UINT64  Previous;\r
+  UINT64  Total;\r
+  UINT64  Start;\r
+  UINT64  End;\r
+  UINT64  Timeout;\r
+  INT64   Cycle;\r
+  INT64   Delta;\r
 \r
-  Tick = 0;\r
-  Start = 0;\r
-  End = 0;\r
   if (PcdGet32 (PcdSpinLockTimeout) > 0) {\r
-    Tick = GetPerformanceCounter ();\r
+    //\r
+    // Get the current timer value\r
+    //\r
+    Current = GetPerformanceCounter();\r
+\r
+    //\r
+    // Initialize local variables\r
+    //\r
+    Start = 0;\r
+    End   = 0;\r
+    Total = 0;\r
+\r
+    //\r
+    // Retrieve the performance counter properties and compute the number of performance\r
+    // counter ticks required to reach the timeout\r
+    //\r
     Timeout = DivU64x32 (\r
                 MultU64x32 (\r
                   GetPerformanceCounterProperties (&Start, &End),\r
@@ -123,16 +140,30 @@ AcquireSpinLock (
                   ),\r
                 1000000\r
                 );\r
-    if (Start < End) {\r
-      Tick += Timeout;\r
-    } else {\r
-      Tick -= Timeout;\r
+    Cycle = End - Start;\r
+    if (Cycle < 0) {\r
+      Cycle = -Cycle;\r
+    }\r
+    Cycle++;\r
+\r
+    while (!AcquireSpinLockOrFail (SpinLock)) {\r
+      CpuPause ();\r
+      Previous = Current;\r
+      Current  = GetPerformanceCounter();\r
+      Delta = (INT64) (Current - Previous);\r
+      if (Start > End) {\r
+        Delta = -Delta;\r
+      }\r
+      if (Delta < 0) {\r
+        Delta += Cycle;\r
+      }\r
+      Total += Delta;\r
+      ASSERT (Total < Timeout);\r
+    }\r
+  } else {\r
+    while (!AcquireSpinLockOrFail (SpinLock)) {\r
+      CpuPause ();\r
     }\r
-  }\r
-\r
-  while (!AcquireSpinLockOrFail (SpinLock)) {\r
-    CpuPause ();\r
-    ASSERT ((Start < End) ^ (Tick <= GetPerformanceCounter ()));\r
   }\r
   return SpinLock;\r
 }\r
@@ -190,7 +221,7 @@ AcquireSpinLockOrFail (
 \r
   @param  SpinLock  A pointer to the spin lock to release.\r
 \r
-  @return SpinLock\r
+  @return SpinLock released lock.\r
 \r
 **/\r
 SPIN_LOCK *\r
@@ -340,6 +371,7 @@ InterlockedCompareExchange64 (
   @param  CompareValue  Pointer value used in compare operation.\r
   @param  ExchangeValue Pointer value used in exchange operation.\r
 \r
+  @return The original *Value before exchange.\r
 **/\r
 VOID *\r
 EFIAPI\r