Use rsp instead of esp to save 64-bit stack pointer.

Signed-off-by: Elvin Li <elvin.li@intel.com>
Reviewed-by: Liming Gao <liming.gao@intel.com>


git-svn-id: https://svn.code.sf.net/p/edk2/code/trunk/edk2@14812 6f19259b-4bc3-4df7-8a09-765794883524

MdePkg/Library/BaseLib/X64/Thunk16.asm

@@ -142,8 +142,8 @@ SavedCr0    DD      ?
 SavedCs     DW      ?
 @64BitCode:
     db      090h 
-    db      067h, 0bch                 ; mov esp, imm32
-SavedSp     DD   ?                     ; restore stack
+    db      048h, 0bch                 ; mov rsp, imm64
+SavedSp     DQ   ?                     ; restore stack
     nop
     ret
 _BackFromUserCode   ENDP
@@ -294,7 +294,7 @@ InternalAsmThunk16  PROC    USES    rbp rbx rsi rdi
     push    r8
     mov     r8d, cs
     mov     [rcx + (SavedCs - SavedCr4)], r8w
-    mov     [rcx + (SavedSp - SavedCr4)], esp
+    mov     [rcx + (SavedSp - SavedCr4)], rsp
     jmp     fword ptr [rcx + (_EntryPoint - SavedCr4)]
 @RetFromRealMode:
     popfq