DuetPkg BootSector:

Update start.asm(S)/start16.asm(S)/start32.asm(S)/efi32.asm(S) under DuetPkg\BootSector to follow the IA32 recommendations on switching to protected mode: Immediately following the MOV CR0 instruction, execute a far JMP or far CALL instruction. (This operation is typically a far jump or call to the next instruction in the instruction stream.)

Signed-off-by: rsun3
Reviewed-by: niruiyu


git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@12723 6f19259b-4bc3-4df7-8a09-765794883524

DuetPkg/BootSector/start.asm

@@ -1,6 +1,6 @@
 ;------------------------------------------------------------------------------
 ;*
-;*   Copyright (c) 2006 - 2007, Intel Corporation. All rights reserved.<BR>
+;*   Copyright (c) 2006 - 2011, Intel Corporation. All rights reserved.<BR>
 ;*   This program and the accompanying materials                          
 ;*   are licensed and made available under the terms and conditions of the BSD License         
 ;*   which accompanies this distribution.  The full text of the license may be found at        
@@ -400,7 +400,7 @@ Timeout8042:
 
 
 A20GateEnabled:
-
+        mov     bx,0008h                    ; Flat data descriptor
 ;
 ; DISABLE INTERRUPTS - Entering Protected Mode
 ;
@@ -421,11 +421,6 @@ A20GateEnabled:
         mov     eax,cr0
         or      al,1
         mov     cr0,eax
-
-        mov eax,0008h                       ; Flat data descriptor
-        mov ebp,000400000h                  ; Destination of EFILDR32
-        mov ebx,000070000h                  ; Length of copy
-        
 JUMP:
 ; jmp far 0010:00020000
         db  066h