; $Id: bs3-cmn-TestIsVmmDevTestingPresent.asm $
;; @file
; BS3Kit - bs3TestIsVmmDevTestingPresent
;

;
; Copyright (C) 2007-2020 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"
%include "VBox/VMMDevTesting.mac"

;*********************************************************************************************************************************
;*  External Symbols                                                                                                             *
;*********************************************************************************************************************************
BS3_EXTERN_DATA16 g_uBs3CpuDetected
TMPL_BEGIN_TEXT


;;
; @cproto   BS3_DECL(bool) bs3TestIsVmmDevTestingPresent_c16(void);
;
BS3_PROC_BEGIN_CMN bs3TestIsVmmDevTestingPresent, BS3_PBC_HYBRID_0_ARGS
        BS3_CALL_CONV_PROLOG 2
        push    xBP
        mov     xBP, xSP
        push    xDX

        ; Check the response from the NOP port.
        mov     dx, VMMDEV_TESTING_IOPORT_NOP
        cmp     byte [g_uBs3CpuDetected], BS3CPU_80386
        jb      .ancient_cpu
        in      eax, dx
        cmp     eax, VMMDEV_TESTING_NOP_RET
.set_ax_and_return:
        mov     ax, 0
        jne     .return
        mov     ax, 1

.return:
        pop     xDX
        pop     xBP
        BS3_CALL_CONV_EPILOG 2
        BS3_HYBRID_RET

.ancient_cpu:
        in      ax, dx
        cmp     ax, (VMMDEV_TESTING_NOP_RET & 0xffff)
        jmp     .set_ax_and_return
BS3_PROC_END_CMN   bs3TestIsVmmDevTestingPresent

