diff options
Diffstat (limited to 'src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetCr4.asm')
| -rw-r--r-- | src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetCr4.asm | 79 |
1 files changed, 79 insertions, 0 deletions
diff --git a/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetCr4.asm b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetCr4.asm new file mode 100644 index 00000000..e897d377 --- /dev/null +++ b/src/VBox/ValidationKit/bootsectors/bs3kit/bs3-cmn-RegGetCr4.asm @@ -0,0 +1,79 @@ +; $Id: bs3-cmn-RegGetCr4.asm $ +;; @file +; BS3Kit - Bs3RegGetCr4 +; + +; +; Copyright (C) 2007-2019 Oracle Corporation +; +; This file is part of VirtualBox Open Source Edition (OSE), as +; available from http://www.virtualbox.org. This file is free software; +; you can redistribute it and/or modify it under the terms of the GNU +; General Public License (GPL) as published by the Free Software +; Foundation, in version 2 as it comes in the "COPYING" file of the +; VirtualBox OSE distribution. VirtualBox OSE is distributed in the +; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind. +; +; The contents of this file may alternatively be used under the terms +; of the Common Development and Distribution License Version 1.0 +; (CDDL) only, as it comes in the "COPYING.CDDL" file of the +; VirtualBox OSE 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. +; + +%include "bs3kit-template-header.mac" + + +BS3_EXTERN_CMN Bs3Panic +BS3_EXTERN_CMN Bs3Syscall +%if TMPL_BITS == 16 +BS3_EXTERN_DATA16 g_bBs3CurrentMode +%endif +TMPL_BEGIN_TEXT + + +;; +; @cproto BS3_CMN_PROTO_STUB(RTCCUINTXREG, Bs3RegGetCr4,(void)); +; +; @returns Register value. +; @remarks Does not require 20h of parameter scratch space in 64-bit mode. +; +; @uses No GPRs (only return full register(s)). +; +BS3_PROC_BEGIN_CMN Bs3RegGetCr4, BS3_PBC_HYBRID_SAFE + BS3_CALL_CONV_PROLOG 0 + push xBP + mov xBP, xSP + +%if TMPL_BITS == 16 + ; If V8086 mode we have to go thru a syscall. + test byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_CODE_V86 + jnz .via_system_call + cmp byte [BS3_DATA16_WRT(g_bBs3CurrentMode)], BS3_MODE_RM + je .direct_access +%endif + ; If not in ring-0, we have to make a system call. + mov ax, ss + and ax, X86_SEL_RPL + jnz .via_system_call + +.direct_access: + mov sAX, cr4 +TONLY16 mov edx, eax +TONLY16 shr edx, 16 + jmp .return + +.via_system_call: + mov xAX, BS3_SYSCALL_GET_CRX + mov dl, 4 + call Bs3Syscall + +.return: + pop xBP + BS3_CALL_CONV_EPILOG 0 + BS3_HYBRID_RET +BS3_PROC_END_CMN Bs3RegGetCr4 + |