| [3] | 1 | ; File name : FindDPT.asm
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| 2 | ; Project name : IDE BIOS
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| 3 | ; Created date : 14.3.2010
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| 4 | ; Last update : 12.4.2010
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| 5 | ; Author : Tomi Tilli
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| 6 | ; Description : Functions for finding Disk Parameter Table.
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| 7 |
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| 8 | ; Section containing code
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| 9 | SECTION .text
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| 10 |
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| 11 | ;--------------------------------------------------------------------
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| 12 | ; Finds pointer to first unused Disk Parameter Table.
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| 13 | ;
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| 14 | ; FindDPT_ForNewDrive
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| 15 | ; Parameters:
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| 16 | ; DS: RAMVARS segment
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| 17 | ; Returns:
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| 18 | ; DS:DI: Ptr to first unused DPT
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| 19 | ; Corrupts registers:
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| 20 | ; Nothing
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| 21 | ;--------------------------------------------------------------------
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| 22 | ALIGN JUMP_ALIGN
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| 23 | FindDPT_ForNewDrive:
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| 24 | push si
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| 25 | mov si, FindDPT_ReturnWrongDPT
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| 26 | jmp SHORT FindDPT_StartIterationAndReturnAfterDone
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| 27 |
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| 28 |
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| 29 | ;--------------------------------------------------------------------
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| 30 | ; Finds Disk Parameter Table for
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| 31 | ; Master or Slave drive at wanted port.
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| 32 | ;
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| 33 | ; FindDPT_ForIdeSlaveAtPort
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| 34 | ; FindDPT_ForIdeMasterAtPort
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| 35 | ; Parameters:
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| 36 | ; DX: IDE Base Port address
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| 37 | ; DS: RAMVARS segment
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| 38 | ; Returns:
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| 39 | ; DL: Drive number (if DPT found)
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| 40 | ; DS:DI: Ptr to DPT
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| 41 | ; CF: Set if wanted DPT found
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| 42 | ; Cleared if DPT not found
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| 43 | ; Corrupts registers:
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| 44 | ; Nothing
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| 45 | ;--------------------------------------------------------------------
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| 46 | ALIGN JUMP_ALIGN
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| 47 | FindDPT_ForIdeSlaveAtPort:
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| 48 | push si
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| 49 | mov si, FindDPT_IterateToSlaveAtPortCallback
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| 50 | jmp SHORT FindDPT_StartIterationAndReturnAfterDone
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| 51 |
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| 52 | ALIGN JUMP_ALIGN
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| 53 | FindDPT_ForIdeMasterAtPort:
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| 54 | push si
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| 55 | mov si, FindDPT_IterateToMasterAtPortCallback
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| 56 | jmp SHORT FindDPT_StartIterationAndReturnAfterDone
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| 57 |
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| 58 | ;--------------------------------------------------------------------
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| 59 | ; Iteration callback for finding DPT using
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| 60 | ; IDE base port for Master or Slave drive.
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| 61 | ;
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| 62 | ; FindDPT_IterateToSlaveAtPortCallback
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| 63 | ; FindDPT_IterateToMasterAtPortCallback
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| 64 | ; Parameters:
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| 65 | ; DX: IDE Base Port address
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| 66 | ; DS:DI: Ptr to DPT to examine
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| 67 | ; Returns:
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| 68 | ; DL: Drive number if correct DPT
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| 69 | ; CF: Set if wanted DPT found
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| 70 | ; Cleared if wrong DPT
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| 71 | ; Corrupts registers:
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| 72 | ; Nothing
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| 73 | ;--------------------------------------------------------------------
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| 74 | ALIGN JUMP_ALIGN
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| 75 | FindDPT_IterateToSlaveAtPortCallback:
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| 76 | test BYTE [di+DPT.bDrvSel], FLG_IDE_DRVHD_DRV
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| 77 | jnz SHORT FindDPT_IterateToMasterOrSlaveAtPortCallback
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| 78 | jmp SHORT FindDPT_ReturnWrongDPT ; Return if master drive
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| 79 |
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| 80 | ALIGN JUMP_ALIGN
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| 81 | FindDPT_IterateToMasterAtPortCallback:
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| 82 | test BYTE [di+DPT.bDrvSel], FLG_IDE_DRVHD_DRV
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| 83 | jnz SHORT FindDPT_ReturnWrongDPT ; Return if slave drive
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| 84 |
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| 85 | ; If BIOS partitioned, ignore all but first partition
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| 86 | ALIGN JUMP_ALIGN
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| 87 | FindDPT_IterateToMasterOrSlaveAtPortCallback:
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| 88 | test BYTE [di+DPT.bFlags], FLG_DPT_PARTITION
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| 89 | jz SHORT .CompareBasePortAddress
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| 90 | test BYTE [di+DPT.bFlags], FLG_DPT_FIRSTPART
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| 91 | jz SHORT FindDPT_ReturnWrongDPT
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| 92 | ALIGN JUMP_ALIGN
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| 93 | .CompareBasePortAddress:
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| 94 | push bx
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| 95 | eMOVZX bx, BYTE [di+DPT.bIdeOff] ; CS:BX now points to IDEVARS
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| 96 | cmp dx, [cs:bx+IDEVARS.wPort] ; Wanted port?
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| 97 | pop bx
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| 98 | jne SHORT FindDPT_ReturnWrongDPT
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| 99 | mov dl, [di+DPT.bDrvNum] ; Load drive number
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| 100 | stc ; Set CF since wanted DPT
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| 101 | ret
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| 102 |
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| 103 |
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| 104 | ;--------------------------------------------------------------------
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| 105 | ; Finds Disk Parameter Table for drive number.
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| 106 | ; IDE Base Port address will be stored to RAMVARS if correct DPT is found.
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| 107 | ;
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| 108 | ; FindDPT_ForDriveNumber
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| 109 | ; Parameters:
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| 110 | ; DL: Drive number
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| 111 | ; DS: RAMVARS segment
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| 112 | ; Returns:
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| 113 | ; DS:DI: Ptr to DPT
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| 114 | ; CF: Set if wanted DPT found
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| 115 | ; Cleared if DPT not found
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| 116 | ; Corrupts registers:
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| 117 | ; Nothing
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| 118 | ;--------------------------------------------------------------------
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| 119 | ALIGN JUMP_ALIGN
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| 120 | FindDPT_ForDriveNumber:
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| 121 | push si
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| 122 | mov si, FindDPT_IterateToDriveNumberCallback
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| 123 | FindDPT_StartIterationAndReturnAfterDone:
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| 124 | call FindDPT_IterateAllDPTs
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| 125 | pop si
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| 126 | ret
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| 127 |
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| 128 | ;--------------------------------------------------------------------
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| 129 | ; Iteration callback for finding DPT for drive number.
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| 130 | ;
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| 131 | ; FindDPT_IterateToDriveNumberCallback
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| 132 | ; Parameters:
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| 133 | ; DL: Drive number to search for
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| 134 | ; DS:DI: Ptr to DPT to examine
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| 135 | ; Returns:
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| 136 | ; CF: Set if wanted DPT found
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| 137 | ; Cleared if wrong DPT
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| 138 | ; Corrupts registers:
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| 139 | ; Nothing
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| 140 | ;--------------------------------------------------------------------
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| 141 | ALIGN JUMP_ALIGN
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| 142 | FindDPT_IterateToDriveNumberCallback:
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| 143 | cmp dl, [di+DPT.bDrvNum] ; Wanted DPT found?
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| 144 | je SHORT FindDPT_RightDriveNumber ; If so, return
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| 145 | FindDPT_ReturnWrongDPT:
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| 146 | clc ; Clear CF since wrong DPT
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| 147 | ret
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| 148 | ALIGN JUMP_ALIGN
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| 149 | FindDPT_RightDriveNumber:
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| 150 | push bx
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| 151 | eMOVZX bx, BYTE [di+DPT.bIdeOff] ; CS:BX now points to IDEVARS
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| 152 | mov bx, [cs:bx+IDEVARS.wPort] ; Load IDE Base Port address...
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| 153 | mov [RAMVARS.wIdeBase], bx ; ...and store it to RAMVARS
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| 154 | pop bx
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| 155 | stc
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| 156 | ret
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| 157 |
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| 158 |
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| 159 | ;--------------------------------------------------------------------
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| 160 | ; Iterates all Disk Parameter Tables.
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| 161 | ;
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| 162 | ; FindDPT_IterateAllDPTs
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| 163 | ; Parameters:
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| 164 | ; BX,DX: Parameters to callback function
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| 165 | ; CS:SI: Ptr to callback function
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| 166 | ; DS: RAMVARS segment
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| 167 | ; Returns:
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| 168 | ; DS:DI: Ptr to wanted DPT (if found)
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| 169 | ; CF: Set if wanted DPT found
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| 170 | ; Cleared if DPT not found
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| 171 | ; Corrupts registers:
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| 172 | ; Nothing, unless corrupted by callback function
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| 173 | ;--------------------------------------------------------------------
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| 174 | ALIGN JUMP_ALIGN
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| 175 | FindDPT_IterateAllDPTs:
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| 176 | push ax
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| 177 | push cx
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| 178 | call FindDPT_PointToFirstDPT ; Point DS:DI to first DPT
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| 179 | eMOVZX cx, BYTE [RAMVARS.bDrvCnt] ; Load number of drives
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| 180 | xor ax, ax ; Zero AX for DPT size and clear CF
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| 181 | jcxz .Return ; Return if no drives
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| 182 | ALIGN JUMP_ALIGN
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| 183 | .LoopWhileDPTsLeft:
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| 184 | call si ; Is wanted DPT?
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| 185 | jc SHORT .Return ; If so, return
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| 186 | mov al, [di+DPT.bSize] ; Load DPT size to AX
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| 187 | add di, ax ; Point to next DPT
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| 188 | loop .LoopWhileDPTsLeft ; Check next DPT
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| 189 | clc ; Clear CF since DPT not found
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| 190 | ALIGN JUMP_ALIGN
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| 191 | .Return:
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| 192 | pop cx
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| 193 | pop ax
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| 194 | ret
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| 195 |
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| 196 |
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| 197 | ;--------------------------------------------------------------------
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| 198 | ; Sets DI to point to first Disk Parameter Table.
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| 199 | ;
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| 200 | ; FindDPT_PointToFirstDPT
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| 201 | ; Parameters:
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| 202 | ; Nothing
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| 203 | ; Returns:
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| 204 | ; DI: Offset to first DPT (even if unused)
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| 205 | ; Corrupts registers:
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| 206 | ; Nothing
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| 207 | ;--------------------------------------------------------------------
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| 208 | ALIGN JUMP_ALIGN
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| 209 | FindDPT_PointToFirstDPT:
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| 210 | mov di, RAMVARS_size
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| 211 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_FULLMODE
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| 212 | jz SHORT .Return ; RAMVARS used (top of interrupt vectors)
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| 213 | add di, BYTE FULLRAMVARS_size-RAMVARS_size ; FULLRAMVARS used (top of base memory)
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| 214 | ALIGN JUMP_ALIGN
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| 215 | .Return:
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| 216 | ret
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