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

1 files changed, 2 insertions, 7 deletions

diff --git a/DuetPkg/BootSector/start32.asm b/DuetPkg/BootSector/start32.asm
index 2cc5640cd8..aaf04b86bc 100644
--- a/DuetPkg/BootSector/start32.asm
+++ b/DuetPkg/BootSector/start32.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        

@@ -408,7 +408,7 @@ Timeout8042:
 

 

 A20GateEnabled:

-

+        mov     bx,0008h                    ; Flat data descriptor

 ;

 ; DISABLE INTERRUPTS - Entering Protected Mode

 ;

@@ -429,11 +429,6 @@ 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