1 files changed, 82 insertions, 0 deletions
diff --git a/MdeModulePkg/Core/Dxe/Misc/Stall.c b/MdeModulePkg/Core/Dxe/Misc/Stall.c
new file mode 100644
index 0000000000..c251f31dc9
--- /dev/null
+++ b/MdeModulePkg/Core/Dxe/Misc/Stall.c
@@ -0,0 +1,82 @@
+/*++
+
+Copyright (c) 2006, 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 <DxeMain.h>
+
+
+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;
+  UINT32  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) DivU64x32Remainder (
+                       Microseconds * 10,
+                       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;
+}