1 | ; Project name : Assembly Library |
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2 | ; Description : DOS Critical Error Handler (24h) replacements. |
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3 | |
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4 | ; |
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5 | ; XTIDE Universal BIOS and Associated Tools |
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6 | ; Copyright (C) 2009-2010 by Tomi Tilli, 2011-2013 by XTIDE Universal BIOS Team. |
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7 | ; |
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8 | ; This program is free software; you can redistribute it and/or modify |
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9 | ; it under the terms of the GNU General Public License as published by |
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10 | ; the Free Software Foundation; either version 2 of the License, or |
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11 | ; (at your option) any later version. |
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12 | ; |
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13 | ; This program is distributed in the hope that it will be useful, |
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14 | ; but WITHOUT ANY WARRANTY; without even the implied warranty of |
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15 | ; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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16 | ; GNU General Public License for more details. |
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17 | ; Visit http://www.gnu.org/licenses/old-licenses/gpl-2.0.html |
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18 | ; |
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19 | |
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20 | ; Note! Only DOS functions 01h - 0Ch, 30h and 59h can be called from a Critical Error Handler. |
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21 | |
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22 | ; DOS Critical Error Handler return values |
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23 | struc CRITICAL_ERROR_ACTION |
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24 | .ignoreErrorAndContinueProcessingRequest resb 1 |
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25 | .retryOperation resb 1 |
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26 | .terminateProgramAsThoughInt21hAH4ChCalled resb 1 |
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27 | .failSystemCallInProgress resb 1 ; Needs DOS 3.1+ |
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28 | endstruc |
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29 | |
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30 | |
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31 | ; Section containing code |
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32 | SECTION .text |
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33 | |
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34 | ;-------------------------------------------------------------------- |
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35 | ; DosCritical_InstallNewHandlerFromCSDX |
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36 | ; Parameters: |
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37 | ; CS:DX: New Critical Error Handler |
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38 | ; Returns: |
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39 | ; Nothing |
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40 | ; Corrupts registers: |
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41 | ; AX |
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42 | ;-------------------------------------------------------------------- |
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43 | ALIGN JUMP_ALIGN |
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44 | DosCritical_InstallNewHandlerFromCSDX: |
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45 | push ds |
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46 | |
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47 | mov al, DOS_CRITICAL_ERROR_HANDLER_24h |
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48 | call HookInterruptVectorInALwithHandlerInCSDX |
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49 | |
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50 | pop ds |
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51 | ret |
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52 | |
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53 | |
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54 | ;-------------------------------------------------------------------- |
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55 | ; DosCritical_RestoreDosHandler |
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56 | ; Parameters: |
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57 | ; Nothing |
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58 | ; Returns: |
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59 | ; Nothing |
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60 | ; Corrupts registers: |
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61 | ; Nothing |
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62 | ;-------------------------------------------------------------------- |
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63 | ALIGN JUMP_ALIGN |
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64 | DosCritical_RestoreDosHandler: |
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65 | push ds |
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66 | push dx |
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67 | push ax |
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68 | |
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69 | lds dx, [cs:PSP.fpInt24hCriticalError] |
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70 | mov ax, (SET_INTERRUPT_VECTOR<<8) | DOS_CRITICAL_ERROR_HANDLER_24h |
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71 | int DOS_INTERRUPT_21h |
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72 | |
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73 | pop ax |
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74 | pop dx |
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75 | pop ds |
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76 | ret |
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77 | |
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78 | |
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79 | ;-------------------------------------------------------------------- |
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80 | ; DosCritical_CustomHandler |
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81 | ; Parameters: |
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82 | ; Nothing |
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83 | ; Returns: |
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84 | ; Nothing |
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85 | ; Corrupts registers: |
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86 | ; Nothing |
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87 | ;-------------------------------------------------------------------- |
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88 | ALIGN JUMP_ALIGN |
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89 | DosCritical_CustomHandler: |
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90 | add sp, 6 ; Remove the INT 24h return address and flags from stack |
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91 | |
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92 | mov ah, GET_EXTENDED_ERROR_INFORMATION ; Requires DOS 3.0+ |
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93 | xor bx, bx |
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94 | int DOS_INTERRUPT_21h |
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95 | mov [cs:bLastCriticalError], al |
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96 | |
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97 | pop ax |
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98 | pop bx |
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99 | pop cx |
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100 | pop dx |
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101 | pop si |
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102 | pop di |
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103 | pop bp |
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104 | pop ds |
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105 | pop es |
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106 | iret ; Return from the INT 21h call |
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107 | |
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108 | bLastCriticalError: db 0 |
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109 | |
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110 | |
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111 | ;-------------------------------------------------------------------- |
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112 | ; DosCritical_HandlerToIgnoreAllErrors |
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113 | ; Parameters: |
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114 | ; Nothing |
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115 | ; Returns: |
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116 | ; AL: CRITICAL_ERROR_ACTION |
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117 | ; Corrupts registers: |
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118 | ; Nothing |
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119 | ;-------------------------------------------------------------------- |
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120 | ALIGN JUMP_ALIGN |
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121 | DosCritical_HandlerToIgnoreAllErrors: |
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122 | mov al, CRITICAL_ERROR_ACTION.ignoreErrorAndContinueProcessingRequest |
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123 | iret |
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124 | |
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