1 files changed, 36 insertions, 0 deletions
diff --git a/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseLib/Ia32/DisableCache.nasm b/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseLib/Ia32/DisableCache.nasm
new file mode 100644
index 00000000..ce83bf41
--- /dev/null
+++ b/src/VBox/Devices/EFI/Firmware/MdePkg/Library/BaseLib/Ia32/DisableCache.nasm
@@ -0,0 +1,36 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006 - 2008, Intel Corporation. All rights reserved.<BR>
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+; Module Name:
+;
+;   DisableCache.Asm
+;
+; Abstract:
+;
+;   Set the CD bit of CR0 to 1, clear the NW bit of CR0 to 0, and flush all caches with a
+;   WBINVD instruction.
+;
+; Notes:
+;
+;------------------------------------------------------------------------------
+
+    SECTION .text
+
+;------------------------------------------------------------------------------
+; VOID
+; EFIAPI
+; AsmDisableCache (
+;   VOID
+;   );
+;------------------------------------------------------------------------------
+global ASM_PFX(AsmDisableCache)
+ASM_PFX(AsmDisableCache):
+    mov     eax, cr0
+    bts     eax, 30
+    btr     eax, 29
+    mov     cr0, eax
+    wbinvd
+    ret
+