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;------------------------------------------------------------------------------
; @file
; Transition from 32 bit flat protected mode into 64 bit flat protected mode
;
; Copyright (c) 2008 - 2018, Intel Corporation. All rights reserved.<BR>
; Copyright (c) 2019, Citrix Systems, Inc.
;
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------
BITS 32
;
; Modified: EAX, EBX, ECX, EDX, ESP
;
Transition32FlatTo64Flat:
OneTimeCall SetCr3ForPageTables64
mov eax, cr4
bts eax, 5 ; enable PAE
mov cr4, eax
mov ecx, 0xc0000080
rdmsr
bts eax, 8 ; set LME
wrmsr
mov eax, cr0
bts eax, 31 ; set PG
mov cr0, eax ; enable paging
;
; backup ESP
;
mov ebx, esp
;
; recalculate delta
;
mov esp, PVH_SPACE(16)
call .delta
.delta:
pop edx
sub edx, ADDR_OF(.delta)
;
; push return addr and seg to the stack, then return far
;
push dword LINEAR_CODE64_SEL
mov eax, ADDR_OF(jumpTo64BitAndLandHere)
add eax, edx ; add delta
push eax
retf
BITS 64
jumpTo64BitAndLandHere:
;
; restore ESP
;
mov esp, ebx
debugShowPostCode POSTCODE_64BIT_MODE
OneTimeCallRet Transition32FlatTo64Flat
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