1 | ; Project name : IDE BIOS |
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2 | ; Description : Functions for initializing the BIOS. |
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3 | |
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4 | ; Section containing code |
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5 | SECTION .text |
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6 | |
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7 | ;-------------------------------------------------------------------- |
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8 | ; Interrupts_InitializeInterruptVectors |
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9 | ; Parameters: |
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10 | ; DS: RAMVARS segment |
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11 | ; ES: BDA and Interrupt Vector segment (zero) |
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12 | ; Returns: |
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13 | ; Nothing |
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14 | ; Corrupts registers: |
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15 | ; All except segments |
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16 | ;-------------------------------------------------------------------- |
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17 | ALIGN JUMP_ALIGN |
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18 | Interrupts_InitializeInterruptVectors: |
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19 | call Interrupts_InitializeInt13hAnd40h |
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20 | call Interrupts_InitializeInt19h |
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21 | jmp SHORT Interrupts_InitializeHardwareIrqHandlers |
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22 | ; Maybe all this should be inlined? |
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23 | |
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24 | |
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25 | ;-------------------------------------------------------------------- |
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26 | ; Interrupts_Int13hAnd40h |
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27 | ; Parameters: |
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28 | ; DS: RAMVARS segment |
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29 | ; ES: BDA and Interrupt Vector segment (zero) |
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30 | ; Returns: |
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31 | ; Nothing |
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32 | ; Corrupts registers: |
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33 | ; AX, BX, CX, DX, SI, DI |
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34 | ;-------------------------------------------------------------------- |
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35 | ALIGN JUMP_ALIGN |
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36 | Interrupts_InitializeInt13hAnd40h: |
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37 | mov ax, [es:INTV_DISK_FUNC*4] ; Load old INT 13h offset |
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38 | mov dx, [es:INTV_DISK_FUNC*4+2] ; Load old INT 13h segment |
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39 | mov [RAMVARS.fpOldI13h], ax ; Store old INT 13h offset |
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40 | mov [RAMVARS.fpOldI13h+2], dx ; Store old INT 13h segment |
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41 | mov bx, INTV_DISK_FUNC ; INT 13h interrupt vector offset |
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42 | mov si, Int13h_DiskFunctions ; Interrupt handler offset |
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43 | call Interrupts_InstallHandlerToVectorInBXFromCSSI |
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44 | |
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45 | ; Only store INT 13h handler to 40h if 40h is not already installed. |
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46 | ; At least AMI BIOS for 286 stores 40h handler by itself and calls |
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47 | ; 40h from 13h. That system locks to infinite loop if we copy 13h to 40h. |
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48 | call FloppyDrive_IsInt40hInstalled |
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49 | jc SHORT .Return |
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50 | mov [es:INTV_FLOPPY_FUNC*4], ax ; Store offset |
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51 | mov [es:INTV_FLOPPY_FUNC*4+2], dx ; Store segment |
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52 | .Return: |
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53 | ret |
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54 | |
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55 | |
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56 | ;-------------------------------------------------------------------- |
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57 | ; Interrupts_InitializeInt19h |
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58 | ; Parameters: |
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59 | ; DS: RAMVARS segment |
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60 | ; ES: BDA and Interrupt Vector segment (zero) |
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61 | ; Returns: |
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62 | ; Nothing |
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63 | ; Corrupts registers: |
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64 | ; BX, SI |
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65 | ;-------------------------------------------------------------------- |
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66 | ALIGN JUMP_ALIGN |
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67 | Interrupts_InitializeInt19h: |
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68 | eMOVZX bx, [cs:ROMVARS.bBootLdrType] ; Load boot loader type |
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69 | mov si, INTV_BOOTSTRAP ; 19h |
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70 | xchg bx, si ; SI=Loader type, BX=19h |
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71 | jmp [cs:si+.rgwSetupBootLoader] ; Jump to install selected loader |
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72 | ALIGN WORD_ALIGN |
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73 | .rgwSetupBootLoader: |
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74 | dw .SetupBootMenuLoader ; BOOTLOADER_TYPE_MENU |
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75 | dw .SetupSimpleLoader ; BOOTLOADER_TYPE_SIMPLE |
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76 | dw .SetupBootMenuLoader ; reserved |
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77 | dw .NoBootLoader ; BOOTLOADER_TYPE_NONE |
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78 | |
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79 | ALIGN JUMP_ALIGN |
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80 | .NoBootLoader: |
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81 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_LATE |
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82 | jnz SHORT .SetupSimpleLoader ; Boot loader required for late initialization |
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83 | ret |
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84 | ALIGN JUMP_ALIGN |
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85 | .SetupSimpleLoader: |
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86 | mov si, Int19h_SimpleBootLoader |
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87 | jmp Interrupts_InstallHandlerToVectorInBXFromCSSI |
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88 | ALIGN JUMP_ALIGN |
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89 | .SetupBootMenuLoader: |
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90 | mov si, Int19hMenu_BootLoader |
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91 | jmp Interrupts_InstallHandlerToVectorInBXFromCSSI |
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92 | |
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93 | |
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94 | ;-------------------------------------------------------------------- |
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95 | ; Interrupts_InitializeHardwareIrqHandlers |
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96 | ; Parameters: |
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97 | ; ES: BDA and Interrupt Vector segment (zero) |
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98 | ; Returns: |
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99 | ; Nothing |
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100 | ; Corrupts registers: |
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101 | ; BX, CX, DX, SI, DI |
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102 | ;-------------------------------------------------------------------- |
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103 | ALIGN JUMP_ALIGN |
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104 | Interrupts_InitializeHardwareIrqHandlers: |
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105 | call RamVars_GetIdeControllerCountToCX |
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106 | mov di, ROMVARS.ideVars0 ; CS:SI points to first IDEVARS |
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107 | ALIGN JUMP_ALIGN |
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108 | .IdeControllerLoop: |
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109 | eMOVZX bx, BYTE [cs:di+IDEVARS.bIRQ] |
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110 | add di, BYTE IDEVARS_size ; Increment to next controller |
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111 | call .InstallLowOrHighIrqHandler |
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112 | loop .IdeControllerLoop |
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113 | .Return: |
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114 | ret ; This ret is shared with .InstallLowOrHighIrqHandler |
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115 | |
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116 | ;-------------------------------------------------------------------- |
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117 | ; .InstallLowOrHighIrqHandler |
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118 | ; Parameters: |
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119 | ; BX: IRQ number, 0 if IRQ disabled |
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120 | ; ES: BDA and Interrupt Vector segment (zero) |
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121 | ; Returns: |
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122 | ; Nothing |
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123 | ; Corrupts registers: |
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124 | ; BX, SI |
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125 | ;-------------------------------------------------------------------- |
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126 | ALIGN JUMP_ALIGN |
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127 | .InstallLowOrHighIrqHandler: |
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128 | test bl, bl |
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129 | jz SHORT .Return ; IRQ not used |
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130 | cmp bl, 8 |
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131 | jb SHORT .InstallLowIrqHandler |
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132 | ; Fall through to .InstallHighIrqHandler |
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133 | |
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134 | ;-------------------------------------------------------------------- |
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135 | ; .InstallHighIrqHandler |
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136 | ; Parameters: |
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137 | ; BX: IRQ number (8...15) |
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138 | ; ES: BDA and Interrupt Vector segment (zero) |
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139 | ; Returns: |
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140 | ; Nothing |
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141 | ; Corrupts registers: |
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142 | ; BX, SI |
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143 | ;-------------------------------------------------------------------- |
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144 | ;ALIGN JUMP_ALIGN |
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145 | ;.InstallHighIrqHandler: |
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146 | add bx, BYTE INTV_IRQ8 - 8 ; Interrupt vector number |
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147 | mov si, HIRQ_InterruptServiceRoutineForIrqs8to15 |
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148 | jmp SHORT Interrupts_InstallHandlerToVectorInBXFromCSSI |
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149 | |
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150 | ;-------------------------------------------------------------------- |
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151 | ; .InstallLowIrqHandler |
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152 | ; Parameters: |
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153 | ; BX: IRQ number (0...7) |
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154 | ; ES: BDA and Interrupt Vector segment (zero) |
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155 | ; Returns: |
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156 | ; Nothing |
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157 | ; Corrupts registers: |
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158 | ; BX, SI |
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159 | ;-------------------------------------------------------------------- |
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160 | ALIGN JUMP_ALIGN |
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161 | .InstallLowIrqHandler: |
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162 | add bx, BYTE INTV_IRQ0 ; Interrupt vector number |
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163 | mov si, HIRQ_InterruptServiceRoutineForIrqs2to7 |
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164 | ; Fall to Interrupts_InstallHandlerToVectorInBXFromCSSI |
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165 | |
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166 | |
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167 | ;-------------------------------------------------------------------- |
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168 | ; Interrupts_InstallHandlerToVectorInBXFromCSSI |
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169 | ; Parameters: |
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170 | ; BX: Interrupt vector number (for example 13h) |
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171 | ; ES: BDA and Interrupt Vector segment (zero) |
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172 | ; CS:SI: Ptr to interrupt handler |
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173 | ; Returns: |
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174 | ; Nothing |
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175 | ; Corrupts registers: |
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176 | ; BX |
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177 | ;-------------------------------------------------------------------- |
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178 | ALIGN JUMP_ALIGN |
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179 | Interrupts_InstallHandlerToVectorInBXFromCSSI: |
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180 | eSHL_IM bx, 2 ; Shift for DWORD offset |
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181 | mov [es:bx], si ; Store offset |
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182 | mov [es:bx+2], cs ; Store segment |
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183 | ret |
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184 | |
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185 | |
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186 | ;-------------------------------------------------------------------- |
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187 | ; Interrupts_UnmaskInterruptControllerForDriveInDSDI |
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188 | ; Parameters: |
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189 | ; DS:DI: Ptr to DPT |
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190 | ; Returns: |
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191 | ; Nothing |
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192 | ; Corrupts registers: |
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193 | ; AX, BX, DX |
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194 | ;-------------------------------------------------------------------- |
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195 | ALIGN JUMP_ALIGN |
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196 | Interrupts_UnmaskInterruptControllerForDriveInDSDI: |
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197 | eMOVZX bx, BYTE [di+DPT.bIdeOff] |
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198 | mov al, [cs:bx+IDEVARS.bIRQ] |
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199 | test al, al |
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200 | jz SHORT .Return ; Interrupts disabled |
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201 | cmp al, 8 |
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202 | jb SHORT .UnmaskLowIrqController |
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203 | ; Fall through to .UnmaskHighIrqController |
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204 | |
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205 | ;-------------------------------------------------------------------- |
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206 | ; .UnmaskHighIrqController |
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207 | ; Parameters: |
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208 | ; AL: IRQ number (8...15) |
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209 | ; Returns: |
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210 | ; Nothing |
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211 | ; Corrupts registers: |
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212 | ; AX, DX |
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213 | ;-------------------------------------------------------------------- |
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214 | ;ALIGN JUMP_ALIGN |
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215 | ;.UnmaskHighIrqController: |
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216 | sub al, 8 ; Slave interrupt number |
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217 | mov dx, PORT_8259SL_IMR ; Load Slave Mask Register address |
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218 | call .ClearBitFrom8259MaskRegister |
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219 | mov al, 2 ; Master IRQ 2 to allow slave IRQs |
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220 | ; Fall to .UnmaskLowIrqController |
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221 | |
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222 | ;-------------------------------------------------------------------- |
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223 | ; .UnmaskLowIrqController |
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224 | ; Parameters: |
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225 | ; AL: IRQ number (0...7) |
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226 | ; Returns: |
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227 | ; Nothing |
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228 | ; Corrupts registers: |
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229 | ; AX, DX |
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230 | ;-------------------------------------------------------------------- |
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231 | ALIGN JUMP_ALIGN |
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232 | .UnmaskLowIrqController: |
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233 | mov dx, PORT_8259MA_IMR ; Load Mask Register address |
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234 | ; Fall to .ClearBitFrom8259MaskRegister |
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235 | |
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236 | ;-------------------------------------------------------------------- |
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237 | ; .ClearBitFrom8259MaskRegister |
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238 | ; Parameters: |
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239 | ; AL: 8259 interrupt index (0...7) |
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240 | ; DX: Port address to Interrupt Mask Register |
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241 | ; Returns: |
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242 | ; Nothing |
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243 | ; Corrupts registers: |
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244 | ; AX |
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245 | ;-------------------------------------------------------------------- |
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246 | ;ALIGN JUMP_ALIGN |
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247 | .ClearBitFrom8259MaskRegister: |
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248 | push cx |
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249 | xchg ax, cx ; IRQ index to CL |
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250 | mov ch, 1 ; Load 1 to be shifted |
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251 | shl ch, cl ; Shift bit to correct position |
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252 | not ch ; Invert to create bit mask for clearing |
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253 | in al, dx ; Read Interrupt Mask Register |
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254 | and al, ch ; Clear wanted bit |
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255 | out dx, al ; Write modified Interrupt Mask Register |
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256 | pop cx |
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257 | .Return: |
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258 | ret |
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