| 1 | ;; @file
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| 2 | ; IPRT - ASMProbeReadByte().
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| 3 | ;
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| 4 |
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| 5 | ;
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| 6 | ; Copyright (C) 2006-2019 Oracle Corporation
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| 7 | ;
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| 8 | ; This file is part of VirtualBox Open Source Edition (OSE), as
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| 9 | ; available from http://www.virtualbox.org. This file is free software;
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| 10 | ; you can redistribute it and/or modify it under the terms of the GNU
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| 11 | ; General Public License (GPL) as published by the Free Software
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| 12 | ; Foundation, in version 2 as it comes in the "COPYING" file of the
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| 13 | ; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 14 | ; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 15 | ;
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| 16 | ; The contents of this file may alternatively be used under the terms
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| 17 | ; of the Common Development and Distribution License Version 1.0
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| 18 | ; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 19 | ; VirtualBox OSE distribution, in which case the provisions of the
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| 20 | ; CDDL are applicable instead of those of the GPL.
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| 21 | ;
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| 22 | ; You may elect to license modified versions of this file under the
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| 23 | ; terms and conditions of either the GPL or the CDDL or both.
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| 24 | ;
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| 25 |
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| 26 | ;*******************************************************************************
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| 27 | ;* Header Files *
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| 28 | ;*******************************************************************************
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| 29 | %include "iprt/asmdefs.mac"
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| 30 |
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| 31 | BEGINCODE
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| 32 |
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| 33 | ;;
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| 34 | ; Probes a byte pointer for read access.
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| 35 | ;
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| 36 | ; While the function will not fault if the byte is not read accessible,
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| 37 | ; the idea is to do this in a safe place like before acquiring locks
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| 38 | ; and such like.
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| 39 | ;
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| 40 | ; Also, this functions guarantees that an eager compiler is not going
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| 41 | ; to optimize the probing away.
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| 42 | ;
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| 43 | ; @param rcx pvByte Pointer to the byte.
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| 44 | BEGINPROC_EXPORTED ASMProbeReadByte
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| 45 | mov al, [rcx]
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| 46 | ret
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| 47 | ENDPROC ASMProbeReadByte
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| 48 |
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