VirtualBox

source: vbox/trunk/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-SwitchTo64Bit.asm@ 78210

Last change on this file since 78210 was 76553, checked in by vboxsync, 6 years ago

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File size: 2.9 KB
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1; $Id: bs3-cmn-SwitchTo64Bit.asm 76553 2019-01-01 01:45:53Z vboxsync $
2;; @file
3; BS3Kit - Bs3SwitchTo64Bit
4;
5
6;
7; Copyright (C) 2007-2019 Oracle Corporation
8;
9; This file is part of VirtualBox Open Source Edition (OSE), as
10; available from http://www.virtualbox.org. This file is free software;
11; you can redistribute it and/or modify it under the terms of the GNU
12; General Public License (GPL) as published by the Free Software
13; Foundation, in version 2 as it comes in the "COPYING" file of the
14; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
15; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
16;
17; The contents of this file may alternatively be used under the terms
18; of the Common Development and Distribution License Version 1.0
19; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
20; VirtualBox OSE distribution, in which case the provisions of the
21; CDDL are applicable instead of those of the GPL.
22;
23; You may elect to license modified versions of this file under the
24; terms and conditions of either the GPL or the CDDL or both.
25;
26
27%include "bs3kit-template-header.mac"
28
29%if TMPL_BITS != 64
30BS3_EXTERN_DATA16 g_bBs3CurrentMode
31TMPL_BEGIN_TEXT
32%endif
33
34
35;;
36; @cproto BS3_DECL(void) Bs3SwitchTo64Bit(void);
37;
38; @remarks Does not require 20h of parameter scratch space in 64-bit mode.
39; @uses No GPRs.
40;
41BS3_PROC_BEGIN_CMN Bs3SwitchTo64Bit, BS3_PBC_NEAR
42%if TMPL_BITS == 64
43 ret
44
45%else
46 %if TMPL_BITS == 16
47 sub sp, 6 ; Space for extended return value (corrected in 64-bit mode).
48 %else
49 push xPRE [xSP] ; Duplicate the return address.
50 and dword [xSP + xCB], 0 ; Clear the high dword or it.
51 %endif
52 push dword 0
53 push sAX
54 push dword 0
55 pushfd
56 cli
57
58 %if TMPL_BITS == 16
59 ; Check that this is LM16
60 mov ax, seg g_bBs3CurrentMode
61 cmp byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_LM16
62 je .ok_lm16
63 int3
64 .ok_lm16:
65 %endif
66
67 ; Calc ring addend.
68 mov ax, cs
69 and xAX, 3
70 shl xAX, BS3_SEL_RING_SHIFT
71 add xAX, BS3_SEL_R0_CS64
72
73 ; setup far return.
74 push sAX
75 %if TMPL_BITS == 16
76 push dword .sixty_four_bit wrt FLAT
77 o32 retf
78 %else
79 push .sixty_four_bit
80 retf
81 %endif
82
83BS3_SET_BITS 64
84.sixty_four_bit:
85
86 ; Load 64-bit segment registers (SS64==DS64).
87 add eax, BS3_SEL_R0_DS64 - BS3_SEL_R0_CS64
88 mov ss, ax
89 mov ds, ax
90 mov es, ax
91
92 ; Update globals.
93 and byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], ~BS3_MODE_CODE_MASK
94 or byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_CODE_64
95
96 %if TMPL_BITS == 16
97 movzx eax, word [rsp + 8*2+6]
98 add eax, BS3_ADDR_BS3TEXT16
99 mov [rsp + 8*2], rax
100 %endif
101
102 popfq
103 pop rax
104 ret
105%endif
106BS3_PROC_END_CMN Bs3SwitchTo64Bit
107
108
109;; @todo far 16-bit variant.
110
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