| 1 | ; Project name : XTIDE Universal BIOS
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| 2 | ; Description : Functions for finding Disk Parameter Table.
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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 | ; Finds pointer to first unused Disk Parameter Table.
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| 9 | ;
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| 10 | ; FindDPT_ForNewDriveToDSDI
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| 11 | ; Parameters:
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| 12 | ; DS: RAMVARS segment
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| 13 | ; Returns:
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| 14 | ; DS:DI: Ptr to first unused DPT
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| 15 | ; Corrupts registers:
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| 16 | ; DL
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| 17 | ;--------------------------------------------------------------------
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| 18 | ALIGN JUMP_ALIGN
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| 19 | FindDPT_ForNewDriveToDSDI:
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| 20 | mov dl, [RAMVARS.bFirstDrv]
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| 21 | add dl, [RAMVARS.bDrvCnt]
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| 22 | ; Fall to FindDPT_ForDriveNumber
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| 23 |
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| 24 |
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| 25 | ;--------------------------------------------------------------------
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| 26 | ; Finds Disk Parameter Table for drive number.
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| 27 | ; IDE Base Port address will be stored to RAMVARS if correct DPT is found.
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| 28 | ;
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| 29 | ; FindDPT_ForDriveNumber
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| 30 | ; Parameters:
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| 31 | ; DL: Drive number
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| 32 | ; DS: RAMVARS segment
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| 33 | ; Returns:
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| 34 | ; DS:DI: Ptr to DPT
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| 35 | ; Corrupts registers:
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| 36 | ; Nothing
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| 37 | ;--------------------------------------------------------------------
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| 38 | ALIGN JUMP_ALIGN
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| 39 | FindDPT_ForDriveNumber:
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| 40 | push dx
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| 41 | xchg di, ax ; Save the contents of AX in DI
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| 42 |
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| 43 | mov al, LARGEST_DPT_SIZE
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| 44 | sub dl, [RAMVARS.bFirstDrv]
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| 45 | mul dl
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| 46 | add ax, BYTE RAMVARS_size
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| 47 |
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| 48 | xchg di, ax ; Restore AX and put result in DI
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| 49 | pop dx
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| 50 | ret
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| 51 |
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| 52 | ;--------------------------------------------------------------------
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| 53 | ; Finds Disk Parameter Table for
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| 54 | ; Master or Slave drive at wanted port.
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| 55 | ;
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| 56 | ; FindDPT_ToDSDIForIdeMasterAtPortDX
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| 57 | ; FindDPT_ToDSDIForIdeSlaveAtPortDX
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| 58 | ; Parameters:
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| 59 | ; DX: IDE Base Port address
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| 60 | ; DS: RAMVARS segment
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| 61 | ; Returns:
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| 62 | ; DL: Drive number (if DPT found)
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| 63 | ; DS:DI: Ptr to DPT
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| 64 | ; CF: Set if wanted DPT found
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| 65 | ; Cleared if DPT not found
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| 66 | ; Corrupts registers:
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| 67 | ; SI
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| 68 | ;
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| 69 | ; Converted to macros since there is only once call site for each of these
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| 70 | ;
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| 71 | ;--------------------------------------------------------------------
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| 72 |
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| 73 | %macro FindDPT_ToDSDIForIdeMasterAtPortDX 0
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| 74 | mov si, IterateToMasterAtPortCallback
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| 75 | call IterateAllDPTs
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| 76 | %endmacro
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| 77 |
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| 78 | %macro FindDPT_ToDSDIForIdeSlaveAtPortDX 0
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| 79 | mov si, IterateToSlaveAtPortCallback
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| 80 | call IterateAllDPTs
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| 81 | %endmacro
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| 82 |
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| 83 |
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| 84 | ;--------------------------------------------------------------------
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| 85 | ; Iteration callback for finding DPT using
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| 86 | ; IDE base port for Master or Slave drive.
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| 87 | ;
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| 88 | ; IterateToSlaveAtPortCallback
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| 89 | ; IterateToMasterAtPortCallback
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| 90 | ; Parameters:
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| 91 | ; CH: Drive number
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| 92 | ; DX: IDE Base Port address
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| 93 | ; DS:DI: Ptr to DPT to examine
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| 94 | ; Returns:
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| 95 | ; DL: Drive number if correct DPT
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| 96 | ; CF: Set if wanted DPT found
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| 97 | ; Cleared if wrong DPT
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| 98 | ; Corrupts registers:
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| 99 | ; Nothing
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| 100 | ;--------------------------------------------------------------------
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| 101 | ALIGN JUMP_ALIGN
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| 102 | IterateToSlaveAtPortCallback:
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| 103 | test BYTE [di+DPT.bFlagsLow], FLGL_DPT_SLAVE ; Clears CF
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| 104 | jnz SHORT CompareBasePortAddress
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| 105 | ret ; Wrong DPT
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| 106 |
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| 107 | ALIGN JUMP_ALIGN
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| 108 | IterateToMasterAtPortCallback:
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| 109 | test BYTE [di+DPT.bFlagsLow], FLGL_DPT_SLAVE
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| 110 | jnz SHORT ReturnWrongDPT ; Return if slave drive
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| 111 |
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| 112 | CompareBasePortAddress:
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| 113 | push bx
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| 114 | eMOVZX bx, BYTE [di+DPT.bIdevarsOffset] ; CS:BX now points to IDEVARS
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| 115 | cmp dx, [cs:bx+IDEVARS.wPort] ; Wanted port?
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| 116 | pop bx
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| 117 | jne SHORT ReturnWrongDPT
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| 118 | mov dl, ch ; Return drive number in DL
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| 119 |
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| 120 | ReturnRightDPT:
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| 121 | stc ; Set CF since wanted DPT
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| 122 | ret
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| 123 |
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| 124 |
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| 125 | ;--------------------------------------------------------------------
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| 126 | ; IterateToDptWithInterruptInServiceFlagSet
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| 127 | ; Parameters:
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| 128 | ; DS:DI: Ptr to DPT to examine
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| 129 | ; Returns:
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| 130 | ; CF: Set if wanted DPT found
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| 131 | ; Cleared if wrong DPT
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| 132 | ; Corrupts registers:
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| 133 | ; Nothing
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| 134 | ;--------------------------------------------------------------------
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| 135 | ALIGN JUMP_ALIGN
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| 136 | IterateToDptWithInterruptInServiceFlagSet:
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| 137 | test BYTE [di+DPT.bFlagsHigh], FLGH_DPT_INTERRUPT_IN_SERVICE ; Clears CF (but we need the clc
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| 138 | ; below anyway for callers above)
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| 139 | jnz SHORT ReturnRightDPT
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| 140 |
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| 141 | ReturnWrongDPT:
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| 142 | clc ; Clear CF since wrong DPT
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| 143 | ret
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| 144 |
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| 145 | ;--------------------------------------------------------------------
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| 146 | ; FindDPT_ToDSDIforInterruptInService
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| 147 | ; Parameters:
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| 148 | ; DS: RAMVARS segment
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| 149 | ; Returns:
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| 150 | ; DS:DI: Ptr to DPT
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| 151 | ; CF: Set if wanted DPT found
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| 152 | ; Cleared if DPT not found
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| 153 | ; Corrupts registers:
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| 154 | ; SI
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| 155 | ;--------------------------------------------------------------------
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| 156 | ALIGN JUMP_ALIGN
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| 157 | FindDPT_ToDSDIforInterruptInService:
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| 158 | mov si, IterateToDptWithInterruptInServiceFlagSet
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| 159 | ; Fall to IterateAllDPTs
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| 160 |
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| 161 | ;--------------------------------------------------------------------
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| 162 | ; Iterates all Disk Parameter Tables.
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| 163 | ;
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| 164 | ; IterateAllDPTs
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| 165 | ; Parameters:
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| 166 | ; AX,BX,DX: Parameters to callback function
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| 167 | ; CS:SI: Ptr to callback function
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| 168 | ; DS: RAMVARS segment
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| 169 | ; Returns:
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| 170 | ; DS:DI: Ptr to wanted DPT (if found)
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| 171 | ; CF: Set if wanted DPT found
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| 172 | ; Cleared if DPT not found, or no DPTs present
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| 173 | ; Corrupts registers:
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| 174 | ; Nothing unless corrupted by callback function
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| 175 | ;--------------------------------------------------------------------
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| 176 | ALIGN JUMP_ALIGN
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| 177 | IterateAllDPTs:
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| 178 | push cx
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| 179 | mov cx, [RAMVARS.wDrvCntAndFirst]
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| 180 | jcxz .NotFound ; Return if no drives
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| 181 | mov di, RAMVARS_size ; Point DS:DI to first DPT
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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 .AllDptsIterated ; If so, return
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| 186 | inc ch ; Increment drive number
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| 187 | add di, BYTE LARGEST_DPT_SIZE ; Point to next DPT
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| 188 | dec cl ; Decrement drives left
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| 189 | jnz SHORT .LoopWhileDPTsLeft
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| 190 | .NotFound:
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| 191 | clc ; Clear CF since DPT not found
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| 192 | ALIGN JUMP_ALIGN
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| 193 | .AllDptsIterated:
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| 194 | pop cx
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| 195 | ret
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