1 | ; $Id: __I4D.asm 98103 2023-01-17 14:15:46Z 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) 2012-2023 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 __I4D
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33 |
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34 | if VBOX_BIOS_CPU lt 80386
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35 | extrn NeedToImplementOn8086__I4D: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 |
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45 | _TEXT segment public 'CODE' use16
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46 | assume cs:_TEXT
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47 |
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48 | ;;
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49 | ; 32-bit signed division.
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50 | ;
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51 | ; @param dx:ax Dividend.
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52 | ; @param cx:bx Divisor.
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53 | ; @returns dx:ax Quotient.
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54 | ; cx:bx Remainder.
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55 | ;
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56 | __I4D:
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57 | pushf
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58 | if VBOX_BIOS_CPU ge 80386
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59 | .386
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60 | push eax
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61 | push edx
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62 | push ecx
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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 | idiv ecx ; eax:edx / ecx -> eax=quotient, edx=remainder.
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73 |
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74 | mov bx, dx
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75 | pop ecx
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76 | shr edx, 16
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77 | mov cx, dx
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78 |
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79 | pop edx
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80 | ror eax, 16
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81 | mov dx, ax
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82 | add sp, 2
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83 | pop ax
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84 | rol eax, 16
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85 | ifdef __WASM__
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86 | .8086
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87 | endif
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88 |
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89 | else
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90 | call NeedToImplementOn8086__I4D
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91 | endif
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92 | popf
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93 | ret
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94 |
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95 |
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96 | _TEXT ends
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97 | end
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98 |
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