| 1 | ; $Id: __I4M.asm 106061 2024-09-16 14:03:52Z vboxsync $
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| 2 | ;; @file
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| 3 | ; Compiler support routines.
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| 4 | ;
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| 5 |
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| 6 | ;
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| 7 | ; Copyright (C) 2012-2024 Oracle and/or its affiliates.
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| 8 | ;
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| 9 | ; This file is part of VirtualBox base platform packages, as
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| 10 | ; available from https://www.virtualbox.org.
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| 11 | ;
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| 12 | ; This program is free software; you can redistribute it and/or
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| 13 | ; modify it under the terms of the GNU General Public License
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| 14 | ; as published by the Free Software Foundation, in version 3 of the
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| 15 | ; License.
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| 16 | ;
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| 17 | ; This program is distributed in the hope that it will be useful, but
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| 18 | ; WITHOUT ANY WARRANTY; without even the implied warranty of
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| 19 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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| 20 | ; General Public License for more details.
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| 21 | ;
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| 22 | ; You should have received a copy of the GNU General Public License
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| 23 | ; along with this program; if not, see <https://www.gnu.org/licenses>.
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| 24 | ;
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| 25 | ; SPDX-License-Identifier: GPL-3.0-only
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| 26 | ;
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| 27 |
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| 28 |
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| 29 | ;*******************************************************************************
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| 30 | ;* Exported Symbols *
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| 31 | ;*******************************************************************************
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| 32 | public __I4M
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| 33 |
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| 34 | if VBOX_BIOS_CPU lt 80386
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| 35 | extrn NeedToImplementOn8086__I4M:near
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| 36 | endif
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| 37 |
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| 38 | ; MASM (ML.EXE) is used for PXE and no longer understands the .8086 directive.
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| 39 | ; WASM is used for the BIOS and understands it just fine.
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| 40 | ifdef __WASM__
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| 41 | .8086
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| 42 | endif
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| 43 |
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| 44 | _TEXT segment public 'CODE' use16
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| 45 | assume cs:_TEXT
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| 46 |
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| 47 | ;;
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| 48 | ; 32-bit signed multiplication.
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| 49 | ;
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| 50 | ; @param dx:ax Factor 1.
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| 51 | ; @param cx:bx Factor 2.
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| 52 | ; @returns dx:ax Result.
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| 53 | ; cx, es may be modified; di is preserved
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| 54 | ;
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| 55 | __I4M:
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| 56 | pushf
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| 57 | if VBOX_BIOS_CPU ge 80386
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| 58 | .386
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| 59 | push eax
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| 60 | push edx
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| 61 | push ecx
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| 62 | push ebx
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| 63 |
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| 64 | rol eax, 16
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| 65 | mov ax, dx
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| 66 | ror eax, 16
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| 67 | xor edx, edx
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| 68 |
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| 69 | shr ecx, 16
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| 70 | mov cx, bx
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| 71 |
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| 72 | imul ecx ; eax * ecx -> edx:eax
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| 73 |
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| 74 | pop ebx
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| 75 | pop ecx
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| 76 |
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| 77 | pop edx
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| 78 | ror eax, 16
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| 79 | mov dx, ax
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| 80 | add sp, 2
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| 81 | pop ax
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| 82 | rol eax, 16
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| 83 | ifdef __WASM__
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| 84 | .8086
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| 85 | endif
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| 86 |
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| 87 | else
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| 88 | call NeedToImplementOn8086__I4M
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| 89 | endif
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| 90 |
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| 91 | popf
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| 92 | ret
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| 93 |
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| 94 |
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| 95 | _TEXT ends
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| 96 | end
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| 97 |
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