| 1 | ; Project name : XTIDE Universal BIOS
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| 2 | ; Description : Functions for initializing the BIOS.
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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, 2011-2012 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 | ; Section containing code
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| 21 | SECTION .text
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| 22 |
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| 23 | ;--------------------------------------------------------------------
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| 24 | ; Drives must be detected before this function is called!
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| 25 | ;
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| 26 | ; Interrupts_InitializeInterruptVectors
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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 | ; All except segments
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| 34 | ;--------------------------------------------------------------------
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| 35 | Interrupts_InitializeInterruptVectors:
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| 36 | ; Install INT 19h handler to properly reset the system
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| 37 | mov al, BIOS_BOOT_LOADER_INTERRUPT_19h ; INT 19h interrupt vector offset
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| 38 | mov si, Int19hReset_Handler ; INT 19h handler to reboot the system
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| 39 | call Interrupts_InstallHandlerToVectorInALFromCSSI
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| 40 |
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| 41 | ; If no drives detected, leave system INT 13h and 40h handlers
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| 42 | ; in place. We need our INT 13h handler to swap drive letters.
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| 43 | %ifndef MODULE_DRIVEXLATE
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| 44 | cmp BYTE [RAMVARS.bDrvCnt], 0
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| 45 | je SHORT Interrupts_InstallHandlerToVectorInALFromCSSI.Interrupts_Return
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| 46 | %endif
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| 47 | ; Fall to .InitializeInt13hAnd40h
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| 48 |
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| 49 | ;--------------------------------------------------------------------
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| 50 | ; .InitializeInt13hAnd40h
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| 51 | ; Parameters:
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| 52 | ; DS: RAMVARS segment
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| 53 | ; ES: BDA and Interrupt Vector segment (zero)
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| 54 | ; Returns:
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| 55 | ; Nothing
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| 56 | ; Corrupts registers:
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| 57 | ; AX, BX, CX, DX, SI, DI
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| 58 | ;--------------------------------------------------------------------
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| 59 | .InitializeInt13hAnd40h:
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| 60 | mov ax, [es:BIOS_DISK_INTERRUPT_13h*4+2]; Load old INT 13h segment
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| 61 | mov [RAMVARS.fpOldI13h+2], ax ; Store old INT 13h segment
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| 62 | xchg dx, ax
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| 63 | mov ax, [es:BIOS_DISK_INTERRUPT_13h*4] ; Load old INT 13h offset
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| 64 | mov [RAMVARS.fpOldI13h], ax ; Store old INT 13h offset
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| 65 |
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| 66 | ; NOTE! Installing INT 40h handler is currently uncommented to test
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| 67 | ; if it is really needed. I suspect that it is not. Many bytes can be
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| 68 | ; saved if INT 40h related code can be removed.
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| 69 | %if 0
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| 70 |
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| 71 | ; Only store INT 13h handler to 40h if 40h is not already installed.
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| 72 | ; At least AMI BIOS for 286 stores 40h handler by itself and calls
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| 73 | ; 40h from 13h. That system locks to infinite loop if we copy 13h to 40h.
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| 74 | call FloppyDrive_IsInt40hInstalled
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| 75 | jc SHORT .Int40hAlreadyInstalled
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| 76 | mov [es:BIOS_DISKETTE_INTERRUPT_40h*4], ax ; Store old INT 13h offset
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| 77 | mov [es:BIOS_DISKETTE_INTERRUPT_40h*4+2], dx ; Store old INT 13h segment
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| 78 | .Int40hAlreadyInstalled:
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| 79 | %endif ; 0
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| 80 |
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| 81 | mov al, BIOS_DISK_INTERRUPT_13h ; INT 13h interrupt vector offset
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| 82 | %ifdef RELOCATE_INT13H_STACK
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| 83 | mov si, Int13h_DiskFunctionsHandlerWithStackChange
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| 84 | %else
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| 85 | mov si, Int13h_DiskFunctionsHandler
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| 86 | %endif
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| 87 |
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| 88 | %ifndef MODULE_IRQ
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| 89 | ; Fall to Interrupts_InstallHandlerToVectorInALFromCSSI
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| 90 | %else
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| 91 | call Interrupts_InstallHandlerToVectorInALFromCSSI
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| 92 | ; Fall to .InitializeHardwareIrqHandlers
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| 93 |
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| 94 | ;--------------------------------------------------------------------
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| 95 | ; .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, AX
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| 102 | ;--------------------------------------------------------------------
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| 103 | .InitializeHardwareIrqHandlers:
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| 104 | call RamVars_GetIdeControllerCountToCX
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| 105 | mov di, ROMVARS.ideVars0+IDEVARS.bIRQ ; CS:SI points to first IDEVARS
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| 106 | .IdeControllerLoop:
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| 107 | mov al, [cs:di]
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| 108 | add di, BYTE IDEVARS_size ; Increment to next controller
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| 109 | call .InstallLowOrHighIrqHandler
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| 110 | loop .IdeControllerLoop
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| 111 | .Return:
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| 112 | ret ; This ret is shared with .InstallLowOrHighIrqHandler
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| 113 |
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| 114 | ;--------------------------------------------------------------------
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| 115 | ; .InstallLowOrHighIrqHandler
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| 116 | ; Parameters:
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| 117 | ; AL: IRQ number, 0 if IRQ disabled
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| 118 | ; ES: BDA and Interrupt Vector segment (zero)
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| 119 | ; Returns:
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| 120 | ; Nothing
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| 121 | ; Corrupts registers:
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| 122 | ; BX, SI
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| 123 | ;--------------------------------------------------------------------
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| 124 | .InstallLowOrHighIrqHandler:
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| 125 | test al, al
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| 126 | jz SHORT .Return ; IRQ not used
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| 127 | cmp al, 8
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| 128 | jb SHORT .InstallLowIrqHandler
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| 129 | ; Fall to .InstallHighIrqHandler
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| 130 |
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| 131 | ;--------------------------------------------------------------------
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| 132 | ; .InstallHighIrqHandler
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| 133 | ; Parameters:
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| 134 | ; BX: IRQ number (8...15)
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| 135 | ; ES: BDA and Interrupt Vector segment (zero)
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| 136 | ; Returns:
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| 137 | ; Nothing
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| 138 | ; Corrupts registers:
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| 139 | ; AL, BX, SI
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| 140 | ;--------------------------------------------------------------------
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| 141 | .InstallHighIrqHandler:
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| 142 | add al, BYTE HARDWARE_IRQ_8_INTERRUPT_70h - 8 ; Interrupt vector number
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| 143 | mov si, IdeIrq_InterruptServiceRoutineForIrqs8to15
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| 144 | jmp SHORT Interrupts_InstallHandlerToVectorInALFromCSSI
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| 145 |
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| 146 | ;--------------------------------------------------------------------
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| 147 | ; .InstallLowIrqHandler
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| 148 | ; Parameters:
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| 149 | ; AL: IRQ number (0...7)
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| 150 | ; ES: BDA and Interrupt Vector segment (zero)
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| 151 | ; Returns:
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| 152 | ; Nothing
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| 153 | ; Corrupts registers:
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| 154 | ; AL, BX, SI
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| 155 | ;--------------------------------------------------------------------
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| 156 | .InstallLowIrqHandler:
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| 157 | add al, BYTE HARDWARE_IRQ_0_INTERRUPT_08h ; Interrupt vector number
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| 158 | mov si, IdeIrq_InterruptServiceRoutineForIrqs2to7
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| 159 | ; Fall to Interrupts_InstallHandlerToVectorInALFromCSSI
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| 160 | %endif ; MODULE_IRQ
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| 161 |
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| 162 |
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| 163 | ;--------------------------------------------------------------------
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| 164 | ; Interrupts_InstallHandlerToVectorInALFromCSSI
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| 165 | ; Parameters:
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| 166 | ; AL: Interrupt vector number (for example 13h)
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| 167 | ; ES: BDA and Interrupt Vector segment (zero)
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| 168 | ; CS:SI: Ptr to interrupt handler
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| 169 | ; Returns:
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| 170 | ; Nothing
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| 171 | ; Corrupts registers:
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| 172 | ; AX, BX
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| 173 | ;--------------------------------------------------------------------
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| 174 | Interrupts_InstallHandlerToVectorInALFromCSSI:
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| 175 | mov bl, 4 ; Shift for DWORD offset, MUL smaller than other alternatives
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| 176 | mul bl
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| 177 | xchg ax, bx
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| 178 | mov [es:bx], si ; Store offset
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| 179 | mov [es:bx+2], cs ; Store segment
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| 180 | .Interrupts_Return:
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| 181 | ret
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| 182 |
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| 183 |
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| 184 | %ifdef MODULE_IRQ
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| 185 | ;--------------------------------------------------------------------
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| 186 | ; Interrupts_UnmaskInterruptControllerForDriveInDSDI
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| 187 | ; Parameters:
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| 188 | ; DS:DI: Ptr to DPT
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| 189 | ; Returns:
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| 190 | ; Nothing
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| 191 | ; Corrupts registers:
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| 192 | ; AX, BX, DX
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| 193 | ;--------------------------------------------------------------------
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| 194 | Interrupts_UnmaskInterruptControllerForDriveInDSDI:
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| 195 | eMOVZX bx, [di+DPT.bIdevarsOffset]
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| 196 | mov al, [cs:bx+IDEVARS.bIRQ]
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| 197 | test al, al
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| 198 | jz SHORT .Return ; Interrupts disabled
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| 199 | cmp al, 8
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| 200 | jb SHORT .UnmaskLowIrqController
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| 201 | ; Fall to .UnmaskHighIrqController
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| 202 |
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| 203 | ;--------------------------------------------------------------------
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| 204 | ; .UnmaskHighIrqController
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| 205 | ; Parameters:
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| 206 | ; AL: IRQ number (8...15)
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| 207 | ; Returns:
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| 208 | ; Nothing
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| 209 | ; Corrupts registers:
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| 210 | ; AX, DX
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| 211 | ;--------------------------------------------------------------------
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| 212 | .UnmaskHighIrqController:
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| 213 | sub al, 8 ; Slave interrupt number
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| 214 | mov dx, SLAVE_8259_IMR
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| 215 | call .ClearBitFrom8259MaskRegister
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| 216 | mov al, 2 ; Master IRQ 2 to allow slave IRQs
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| 217 | ; Fall to .UnmaskLowIrqController
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| 218 |
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| 219 | ;--------------------------------------------------------------------
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| 220 | ; .UnmaskLowIrqController
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| 221 | ; Parameters:
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| 222 | ; AL: IRQ number (0...7)
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| 223 | ; Returns:
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| 224 | ; Nothing
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| 225 | ; Corrupts registers:
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| 226 | ; AX, DX
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| 227 | ;--------------------------------------------------------------------
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| 228 | .UnmaskLowIrqController:
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| 229 | mov dx, MASTER_8259_IMR
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| 230 | ; Fall to .ClearBitFrom8259MaskRegister
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| 231 |
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| 232 | ;--------------------------------------------------------------------
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| 233 | ; .ClearBitFrom8259MaskRegister
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| 234 | ; Parameters:
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| 235 | ; AL: 8259 interrupt index (0...7)
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| 236 | ; DX: Port address to Interrupt Mask Register
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| 237 | ; Returns:
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| 238 | ; Nothing
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| 239 | ; Corrupts registers:
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| 240 | ; AX
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| 241 | ;--------------------------------------------------------------------
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| 242 | .ClearBitFrom8259MaskRegister:
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| 243 | push cx
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| 244 | xchg ax, cx ; IRQ index to CL
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| 245 | mov ch, 1 ; Load 1 to be shifted
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| 246 | shl ch, cl ; Shift bit to correct position
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| 247 | not ch ; Invert to create bit mask for clearing
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| 248 | in al, dx ; Read Interrupt Mask Register
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| 249 | and al, ch ; Clear wanted bit
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| 250 | out dx, al ; Write modified Interrupt Mask Register
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| 251 | pop cx
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| 252 | .Return:
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| 253 | ret
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| 254 |
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| 255 | %endif ; MODULE_IRQ
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