1 files changed, 38 insertions, 0 deletions
diff --git a/roms/edk2/MdePkg/Library/BaseLib/Ia32/Mwait.c b/roms/edk2/MdePkg/Library/BaseLib/Ia32/Mwait.c
new file mode 100644
index 000000000..08c666f79
--- /dev/null
+++ b/roms/edk2/MdePkg/Library/BaseLib/Ia32/Mwait.c
@@ -0,0 +1,38 @@
+/** @file
+  AsmMwait function
+
+  Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+/**
+  Executes an MWAIT instruction.
+
+  Executes an MWAIT instruction with the register state specified by Eax and
+  Ecx. Returns Eax. This function is only available on IA-32 and x64.
+
+  @param  RegisterEax The value to load into EAX or RAX before executing the MONITOR
+                      instruction.
+  @param  RegisterEcx The value to load into ECX or RCX before executing the MONITOR
+                      instruction.
+
+  @return RegisterEax
+
+**/
+UINTN
+EFIAPI
+AsmMwait (
+  IN      UINTN                     RegisterEax,
+  IN      UINTN                     RegisterEcx
+  )
+{
+  _asm {
+    mov     eax, RegisterEax
+    mov     ecx, RegisterEcx
+    _emit   0x0f              // mwait
+    _emit   0x01
+    _emit   0xC9
+  }
+}
+