CloverBootloader/UefiCpuPkg/ResetVector/Vtf0/Ia32/Flat32ToFlat64.asm

40 lines
1016 B
NASM

;------------------------------------------------------------------------------
; @file
; Transition from 32 bit flat protected mode into 64 bit flat protected mode
;
; Copyright (c) 2008 - 2018, Intel Corporation. All rights reserved.<BR>
; SPDX-License-Identifier: BSD-2-Clause-Patent
;
;------------------------------------------------------------------------------
BITS 32
;
; Modified: EAX
;
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
jmp LINEAR_CODE64_SEL:ADDR_OF(jumpTo64BitAndLandHere)
BITS 64
jumpTo64BitAndLandHere:
debugShowPostCode POSTCODE_64BIT_MODE
OneTimeCallRet Transition32FlatTo64Flat