1 files changed, 66 insertions, 0 deletions
diff --git a/roms/edk2/EmulatorPkg/Sec/X64/SwitchRam.S b/roms/edk2/EmulatorPkg/Sec/X64/SwitchRam.S
new file mode 100644
index 000000000..59d4e2ede
--- /dev/null
+++ b/roms/edk2/EmulatorPkg/Sec/X64/SwitchRam.S
@@ -0,0 +1,66 @@
+#------------------------------------------------------------------------------
+#
+# Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
+# Portions copyright (c) 2011, Apple Inc. All rights reserved.
+# SPDX-License-Identifier: BSD-2-Clause-Patent
+#
+#------------------------------------------------------------------------------
+
+
+
+//  EFI_STATUS
+//  EFIAPI
+//  SecTemporaryRamSupport (
+//    IN CONST EFI_PEI_SERVICES   **PeiServices,         // %rcx
+//    IN EFI_PHYSICAL_ADDRESS     TemporaryMemoryBase,   // %rdx
+//    IN EFI_PHYSICAL_ADDRESS     PermanentMemoryBase,   // %r8
+//    IN UINTN                    CopySize               // %r9
+//    )
+//
+ASM_GLOBAL ASM_PFX(SecTemporaryRamSupport)
+ASM_PFX(SecTemporaryRamSupport):
+  // Adjust callers %rbp to account for stack move
+  subq    %rdx, %rbp     // Calc offset of %rbp in Temp Memory
+  addq    %r8,  %rbp     // add in permanent base to offset
+
+  pushq   %rbp           // stack frame is for the debugger
+  movq    %rsp, %rbp
+
+  pushq   %rdx          // Save TemporaryMemoryBase
+  pushq   %r8           // Save PermanentMemoryBase
+  pushq   %r9           // Save CopySize
+
+  //
+  // Copy all of temp RAM to permanent memory, including stack
+  //
+  // CopyMem (PermanentMemoryBase, TemporaryMemoryBase, CopySize);
+  //          %rcx,                %rdx,                %r8
+  movq    %r8,  %rcx    // Shift arguments
+  movq    %r9,  %r8
+  subq    $0x28, %rsp   // Allocate register spill area & 16-byte align stack
+  call    ASM_PFX(CopyMem)
+  // Temp mem stack now copied to permanent location. %esp still in temp memory
+  addq    $0x28, %rsp
+
+  popq    %r9           // CopySize (old stack)
+  popq    %r8           // PermanentMemoryBase (old stack)
+  popq    %rdx          // TemporaryMemoryBase (old stack)
+
+  movq    %rsp, %rcx    // Move to new stack
+  subq    %rdx, %rcx    // Calc offset of stack in Temp Memory
+  addq    %r8,  %rcx    // Calc PermanentMemoryBase address
+  movq    %rcx, %rsp    // Update stack
+  // Stack now points to permanent memory
+
+  // ZeroMem (TemporaryMemoryBase /* rcx */, CopySize /* rdx */);
+  movq    %rdx, %rcx
+  movq    %r9,  %rdx
+  subq    $0x28, %rsp   // Allocate register spill area & 16-byte align stack
+  call    ASM_PFX(ZeroMem)
+  addq    $0x28, %rsp
+
+  // This data comes off the NEW stack
+  popq    %rbp
+  ret
+
+