1 files changed, 70 insertions, 0 deletions
diff --git a/roms/edk2/EmulatorPkg/Sec/X64/SwitchRam.asm b/roms/edk2/EmulatorPkg/Sec/X64/SwitchRam.asm
new file mode 100644
index 000000000..e66bda5bf
--- /dev/null
+++ b/roms/edk2/EmulatorPkg/Sec/X64/SwitchRam.asm
@@ -0,0 +1,70 @@
+;------------------------------------------------------------------------------
+;
+; Copyright (c) 2006 - 2012, Intel Corporation. All rights reserved.<BR>
+; Portions copyright (c) 2011, Apple Inc. All rights reserved.
+; SPDX-License-Identifier: BSD-2-Clause-Patent
+;
+;------------------------------------------------------------------------------
+
+EXTERN CopyMem:PROC
+EXTERN ZeroMem:PROC
+
+    .code
+
+;------------------------------------------------------------------------------
+;  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
+;    )
+;------------------------------------------------------------------------------
+SecTemporaryRamSupport PROC
+  ; Adjust callers %rbp to account for stack move
+  sub     rbp, rdx      ; Calc offset of %rbp in Temp Memory
+  add     rbp, r8       ; add in permanent base to offset
+
+  push    rbp           ; stack frame is for the debugger
+  mov     rbp, rsp
+
+  push    rdx           ; Save TemporaryMemoryBase
+  push    r8            ; Save PermanentMemoryBase
+  push    r9            ; Save CopySize
+
+  ;
+  ; Copy all of temp RAM to permanent memory, including stack
+  ;
+  ; CopyMem (PermanentMemoryBase, TemporaryMemoryBase, CopySize);
+  ;          %rcx,                %rdx,                %r8
+  mov     rcx, r8       ; Shift arguments
+  mov     r8, r9
+  sub     rsp, 028h     ; Allocate register spill area & 16-byte align stack
+  call    CopyMem
+  ; Temp mem stack now copied to permanent location. %esp still in temp memory
+  add     rsp, 028h
+
+  pop     r9            ; CopySize (old stack)
+  pop     r8            ; PermanentMemoryBase (old stack)
+  pop     rdx           ; TemporaryMemoryBase (old stack)
+
+  mov     rcx, rsp      ; Move to new stack
+  sub     rcx, rdx      ; Calc offset of stack in Temp Memory
+  add     rcx, r8       ; Calc PermanentMemoryBase address
+  mov     rsp, rcx      ; Update stack
+  ; Stack now points to permanent memory
+
+  ; ZeroMem (TemporaryMemoryBase /* rcx */, CopySize /* rdx */);
+  mov     rcx, rdx
+  mov     rdx, r9
+  sub     rsp, 028h     ; Allocate register spill area & 16-byte align stack
+  call    ZeroMem
+  add     rsp, 028h
+
+  ; This data comes off the NEW stack
+  pop     rbp
+  ret
+SecTemporaryRamSupport ENDP
+
+  END