| 1 | ; $Id: alloca-x86-r0drv-nt.asm 86190 2020-09-21 08:54:23Z vboxsync $
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| 2 | ;; @file
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| 3 | ; IPRT - Visual C++ __alloca__probe_16.
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2020 Oracle Corporation
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| 8 | ;
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| 9 | ; This file is part of VirtualBox Open Source Edition (OSE), as
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| 10 | ; available from http://www.virtualbox.org. This file is free software;
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| 11 | ; you can redistribute it and/or modify it under the terms of the GNU
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| 12 | ; General Public License (GPL) as published by the Free Software
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| 13 | ; Foundation, in version 2 as it comes in the "COPYING" file of the
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| 14 | ; VirtualBox OSE distribution. VirtualBox OSE is distributed in the
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| 15 | ; hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
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| 16 | ;
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| 17 | ; The contents of this file may alternatively be used under the terms
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| 18 | ; of the Common Development and Distribution License Version 1.0
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| 19 | ; (CDDL) only, as it comes in the "COPYING.CDDL" file of the
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| 20 | ; VirtualBox OSE distribution, in which case the provisions of the
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| 21 | ; CDDL are applicable instead of those of the GPL.
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| 22 | ;
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| 23 | ; You may elect to license modified versions of this file under the
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| 24 | ; terms and conditions of either the GPL or the CDDL or both.
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| 25 | ;
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| 26 |
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| 27 | ;*******************************************************************************
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| 28 | ;* Header Files *
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| 29 | ;*******************************************************************************
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| 30 | %include "iprt/asmdefs.mac"
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| 31 |
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| 32 | BEGINCODE
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| 33 |
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| 34 | ;;
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| 35 | ; @returns esp with eax subtracted and aligned to 16 bytes.
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| 36 | ; @param eax allocation size.
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| 37 | ;
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| 38 | BEGINPROC _alloca_probe_16
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| 39 | ; Sanitycheck the input.
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| 40 | %ifdef DEBUG
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| 41 | cmp eax, 0
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| 42 | jne .not_zero
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| 43 | int3
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| 44 | .not_zero:
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| 45 | cmp eax, 4096
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| 46 | jbe .four_kb_or_less
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| 47 | int3
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| 48 | .four_kb_or_less:
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| 49 | %endif
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| 50 |
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| 51 | ; Don't bother probing the stack as the allocation is supposed to be
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| 52 | ; a lot smaller than 4KB.
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| 53 | neg eax
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| 54 | lea eax, [esp + eax + 4]
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| 55 | and eax, 0fffffff0h
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| 56 | xchg eax, esp
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| 57 | jmp [eax]
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| 58 | ENDPROC _alloca_probe_16
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| 59 |
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