From b7c51c9cf4864df6aabb99a1ae843becd577237c Mon Sep 17 00:00:00 2001
From: raywu <raywu0301@gmail.com>
Date: Fri, 15 Jun 2018 00:00:50 +0800
Subject: init. 1AQQW051

---
 EDK/Foundation/Core/Dxe/Misc/Stall.c | 79 ++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 EDK/Foundation/Core/Dxe/Misc/Stall.c

(limited to 'EDK/Foundation/Core/Dxe/Misc/Stall.c')

diff --git a/EDK/Foundation/Core/Dxe/Misc/Stall.c b/EDK/Foundation/Core/Dxe/Misc/Stall.c
new file mode 100644
index 0000000..a87f894
--- /dev/null
+++ b/EDK/Foundation/Core/Dxe/Misc/Stall.c
@@ -0,0 +1,79 @@
+/*++
+
+Copyright (c) 2004, Intel Corporation                                                         
+All rights reserved. This program and the accompanying materials                          
+are licensed and made available under the terms and conditions of the BSD License         
+which accompanies this distribution.  The full text of the license may be found at        
+http://opensource.org/licenses/bsd-license.php                                            
+                                                                                          
+THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,                     
+WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.             
+
+Module Name:
+
+    Stall.c
+
+Abstract:
+
+    Tiano Miscellaneous Services Stall service implementation
+
+--*/
+
+//
+// Include statements
+//
+
+#include "Tiano.h"
+#include "DxeCore.h"
+
+EFI_BOOTSERVICE
+EFI_STATUS
+EFIAPI
+CoreStall (
+  IN UINTN            Microseconds
+  )
+/*++
+
+Routine Description:
+
+  Introduces a fine-grained stall.
+
+Arguments:
+
+  Microseconds      The number of microseconds to stall execution
+
+Returns:
+
+  EFI_SUCCESS            - Execution was stalled for at least the requested amount
+                           of microseconds.
+
+  EFI_NOT_AVAILABLE_YET  - gMetronome is not available yet
+
+--*/
+{
+  UINT32  Counter;
+  UINTN   Remainder;
+
+  if (gMetronome == NULL) {
+    return EFI_NOT_AVAILABLE_YET;
+  }
+  
+  //
+  // Calculate the number of ticks by dividing the number of microseconds by
+  // the TickPeriod.
+  // Calcullation is based on 100ns unit.
+  //
+  Counter = (UINT32) DivU64x32 ((Microseconds * 10), (UINTN) gMetronome->TickPeriod, &Remainder);
+
+  //
+  // Call WaitForTick for Counter + 1 ticks to try to guarantee Counter tick
+  // periods, thus attempting to ensure Microseconds of stall time.
+  //
+  if (Remainder != 0) {
+    Counter++;
+  }
+
+  gMetronome->WaitForTick (gMetronome, Counter);
+
+  return EFI_SUCCESS;
+}
-- 
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