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|
; $Id: bs3-cmn-SwitchTo64Bit.asm $
;; @file
; BS3Kit - Bs3SwitchTo64Bit
;
;
; Copyright (C) 2007-2023 Oracle and/or its affiliates.
;
; This file is part of VirtualBox base platform packages, as
; available from https://www.virtualbox.org.
;
; This program is free software; you can redistribute it and/or
; modify it under the terms of the GNU General Public License
; as published by the Free Software Foundation, in version 3 of the
; License.
;
; This program is distributed in the hope that it will be useful, but
; WITHOUT ANY WARRANTY; without even the implied warranty of
; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
; General Public License for more details.
;
; You should have received a copy of the GNU General Public License
; along with this program; if not, see <https://www.gnu.org/licenses>.
;
; The contents of this file may alternatively be used under the terms
; of the Common Development and Distribution License Version 1.0
; (CDDL), a copy of it is provided in the "COPYING.CDDL" file included
; in the VirtualBox distribution, in which case the provisions of the
; CDDL are applicable instead of those of the GPL.
;
; You may elect to license modified versions of this file under the
; terms and conditions of either the GPL or the CDDL or both.
;
; SPDX-License-Identifier: GPL-3.0-only OR CDDL-1.0
;
%include "bs3kit-template-header.mac"
%if TMPL_BITS != 64
BS3_EXTERN_DATA16 g_bBs3CurrentMode
TMPL_BEGIN_TEXT
%endif
;;
; @cproto BS3_DECL(void) Bs3SwitchTo64Bit(void);
;
; @remarks Does not require 20h of parameter scratch space in 64-bit mode.
; @uses No GPRs.
;
BS3_PROC_BEGIN_CMN Bs3SwitchTo64Bit, BS3_PBC_NEAR
%if TMPL_BITS == 64
ret
%else
%if TMPL_BITS == 16
sub sp, 6 ; Space for extended return value (corrected in 64-bit mode).
%else
push xPRE [xSP] ; Duplicate the return address.
and dword [xSP + xCB], 0 ; Clear the high dword or it.
%endif
push dword 0
push sAX
push dword 0
pushfd
cli
%if TMPL_BITS == 16
; Check that this is LM16
mov ax, seg g_bBs3CurrentMode
cmp byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_LM16
je .ok_lm16
int3
.ok_lm16:
%endif
; Calc ring addend.
mov ax, cs
and xAX, 3
shl xAX, BS3_SEL_RING_SHIFT
add xAX, BS3_SEL_R0_CS64
; setup far return.
push sAX
%if TMPL_BITS == 16
push dword .sixty_four_bit wrt FLAT
o32 retf
%else
push .sixty_four_bit
retf
%endif
BS3_SET_BITS 64
.sixty_four_bit:
; Load 64-bit segment registers (SS64==DS64).
add eax, BS3_SEL_R0_DS64 - BS3_SEL_R0_CS64
mov ss, ax
mov ds, ax
mov es, ax
; Update globals.
and byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], ~BS3_MODE_CODE_MASK
or byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_CODE_64
%if TMPL_BITS == 16
movzx eax, word [rsp + 8*2+6]
add eax, BS3_ADDR_BS3TEXT16
mov [rsp + 8*2], rax
%endif
popfq
pop rax
ret
%endif
BS3_PROC_END_CMN Bs3SwitchTo64Bit
;; @todo far 16-bit variant.
|
