| 1 | ; Project name : XTIDE Universal BIOS
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| 2 | ; Description : Functions for creating 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 | ; Creates new Disk Parameter Table for detected hard disk.
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| 9 | ; Drive is then fully accessible using any BIOS function.
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| 10 | ;
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| 11 | ; CreateDPT_FromAtaInformation
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| 12 | ; Parameters:
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| 13 | ; BH: Drive Select byte for Drive and Head Register
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| 14 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 15 | ; CS:BP: Ptr to IDEVARS for the controller
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| 16 | ; DS: RAMVARS segment
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| 17 | ; ES: BDA Segment
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| 18 | ; Returns:
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| 19 | ; DL: Drive number for new drive
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| 20 | ; DS:DI: Ptr to Disk Parameter Table (if succesfull)
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| 21 | ; CF: Cleared if DPT created successfully
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| 22 | ; Set if any error
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| 23 | ; Corrupts registers:
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| 24 | ; AX, BX, CX, DH
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| 25 | ;--------------------------------------------------------------------
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| 26 | CreateDPT_FromAtaInformation:
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| 27 | call FindDPT_ForNewDriveToDSDI
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| 28 | ; Fall to .InitializeDPT
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| 29 |
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| 30 | ;--------------------------------------------------------------------
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| 31 | ; .InitializeDPT
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| 32 | ; Parameters:
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| 33 | ; BH: Drive Select byte for Drive and Head Register
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| 34 | ; DS:DI: Ptr to Disk Parameter Table
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| 35 | ; CS:BP: Ptr to IDEVARS for the controller
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| 36 | ; Returns:
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| 37 | ; Nothing
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| 38 | ; Corrupts registers:
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| 39 | ; AX
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| 40 | ;--------------------------------------------------------------------
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| 41 | .InitializeDPT:
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| 42 | mov [di+DPT.bIdevarsOffset], bp ; IDEVARS must start in first 256 bytes of ROM
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| 43 | ; Fall to .StoreDriveSelectAndDriveControlByte
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| 44 |
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| 45 | ;--------------------------------------------------------------------
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| 46 | ; .StoreDriveSelectAndDriveControlByte
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| 47 | ; Parameters:
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| 48 | ; BH: Drive Select byte for Drive and Head Register
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| 49 | ; DS:DI: Ptr to Disk Parameter Table
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| 50 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 51 | ; CS:BP: Ptr to IDEVARS for the controller
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| 52 | ; Returns:
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| 53 | ; Nothing
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| 54 | ; Corrupts registers:
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| 55 | ; AX
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| 56 | ;--------------------------------------------------------------------
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| 57 | .StoreDriveSelectAndDriveControlByte:
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| 58 | mov al, bh
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| 59 | and ax, BYTE FLG_DRVNHEAD_DRV ; AL now has Master/Slave bit
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| 60 | cmp [cs:bp+IDEVARS.bIRQ], ah ; Interrupts enabled?
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| 61 | jz SHORT .StoreFlags ; If not, do not set interrupt flag
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| 62 | or al, FLG_DPT_ENABLE_IRQ
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| 63 | .StoreFlags:
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| 64 | mov [di+DPT.wFlags], ax
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| 65 | ; Fall to .StorePCHS
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| 66 |
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| 67 | ;--------------------------------------------------------------------
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| 68 | ; .StorePCHS
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| 69 | ; Parameters:
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| 70 | ; BH: Drive Select byte for Drive and Head Register
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| 71 | ; DS:DI: Ptr to Disk Parameter Table
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| 72 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 73 | ; CS:BP: Ptr to IDEVARS for the controller
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| 74 | ; Returns:
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| 75 | ; AX: P-CHS cylinders
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| 76 | ; BL: P-CHS heads
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| 77 | ; BH: P-CHS sectors
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| 78 | ; Corrupts registers:
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| 79 | ; Nothing
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| 80 | ;--------------------------------------------------------------------
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| 81 | .StorePCHS:
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| 82 | mov al, FLG_DRVPARAMS_USERCHS ; User specified CHS?
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| 83 | call AccessDPT_TestIdeVarsFlagsForMasterOrSlaveDrive
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| 84 | jnz SHORT .GetUserSpecifiedPCHS
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| 85 | call AtaID_GetPCHS ; Get from ATA information
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| 86 | jmp SHORT .StorePCHStoDPT
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| 87 |
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| 88 | .GetUserSpecifiedPCHS:
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| 89 | call AccessDPT_GetPointerToDRVPARAMStoCSBX
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| 90 | mov ax, [cs:bx+DRVPARAMS.wCylinders]
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| 91 | mov bx, [cs:bx+DRVPARAMS.wHeadsAndSectors]
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| 92 |
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| 93 | .StorePCHStoDPT:
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| 94 | mov [di+DPT.wPchsCylinders], ax
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| 95 | mov [di+DPT.wPchsHeadsAndSectors], bx
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| 96 | ; Fall to .StoreLCHS
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| 97 |
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| 98 | ;--------------------------------------------------------------------
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| 99 | ; .StoreLCHS
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| 100 | ; Parameters:
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| 101 | ; AX: P-CHS cylinders
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| 102 | ; BL: P-CHS heads
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| 103 | ; DS:DI: Ptr to Disk Parameter Table
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| 104 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 105 | ; Returns:
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| 106 | ; Nothing
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| 107 | ; Corrupts registers:
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| 108 | ; AX, BX, CX
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| 109 | ;--------------------------------------------------------------------
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| 110 | .StoreLCHS:
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| 111 | xor bh, bh ; BX = P-CHS Heads (1...16)
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| 112 | xor cx, cx
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| 113 | .ShiftLoop:
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| 114 | cmp ax, 1024 ; Need to shift?
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| 115 | jbe SHORT .LimitHeadsTo255 ; If not, return
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| 116 | inc cx ; Increment shift count
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| 117 | shr ax, 1 ; Halve cylinders
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| 118 | shl bx, 1 ; Double heads
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| 119 | jmp SHORT .ShiftLoop
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| 120 |
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| 121 | .LimitHeadsTo255: ; DOS does not support drives with 256 heads
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| 122 | rcr bh, 1 ; Set CF if 256 heads
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| 123 | sbb bl, 0 ; Decrement to 255 if 256 heads
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| 124 | or [di+DPT.wFlags], cl
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| 125 | mov [di+DPT.bLchsHeads], bl
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| 126 | ; Fall to .StoreAddressing
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| 127 |
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| 128 | ;--------------------------------------------------------------------
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| 129 | ; .StoreAddressing
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| 130 | ; Parameters:
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| 131 | ; DS:DI: Ptr to Disk Parameter Table
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| 132 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 133 | ; Returns:
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| 134 | ; Nothing
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| 135 | ; Corrupts registers:
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| 136 | ; AX, BX
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| 137 | ;--------------------------------------------------------------------
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| 138 | .StoreAddressing:
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| 139 | ; Check if L-CHS addressing should be used
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| 140 | cmp WORD [di+DPT.wPchsCylinders], 1024 ; L-CHS possible? (no translation needed)
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| 141 | jbe SHORT .StoreBlockMode ; If so, nothing needs to be changed
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| 142 |
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| 143 | ; Check if P-CHS addressing should be used
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| 144 | mov al, FLG_DRVPARAMS_USERCHS ; User specified CHS?
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| 145 | call AccessDPT_TestIdeVarsFlagsForMasterOrSlaveDrive
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| 146 | jnz SHORT .StorePCHSaddressing
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| 147 | test WORD [es:si+ATA1.wCaps], A2_wCaps_LBA
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| 148 | jz SHORT .StorePCHSaddressing ; Use P-CHS since LBA not supported
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| 149 |
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| 150 | ; LBA needs to be used. Check if 48-bit LBA is supported
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| 151 | test WORD [es:si+ATA6.wSetSup83], A6_wSetSup83_LBA48
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| 152 | jz SHORT .StoreLBA28addressing ; Use LBA-28 since LBA-48 not supported
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| 153 | or BYTE [di+DPT.wFlags], ADDRESSING_MODE_LBA48<<ADDRESSING_MODE_FIELD_POSITION
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| 154 | .StoreLBA28addressing:
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| 155 | or BYTE [di+DPT.wFlags], ADDRESSING_MODE_LBA28<<ADDRESSING_MODE_FIELD_POSITION
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| 156 | jmp SHORT .StoreBlockMode
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| 157 | .StorePCHSaddressing:
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| 158 | or BYTE [di+DPT.wFlags], ADDRESSING_MODE_PCHS<<ADDRESSING_MODE_FIELD_POSITION
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| 159 | ; Fall to .StoreBlockMode
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| 160 |
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| 161 | ;--------------------------------------------------------------------
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| 162 | ; .StoreBlockMode
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| 163 | ; Parameters:
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| 164 | ; DS:DI: Ptr to Disk Parameter Table
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| 165 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 166 | ; Returns:
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| 167 | ; Nothing
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| 168 | ; Corrupts registers:
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| 169 | ; Nothing
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| 170 | ;--------------------------------------------------------------------
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| 171 | .StoreBlockMode:
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| 172 | cmp BYTE [es:si+ATA1.bBlckSize], 1 ; Max block size in sectors
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| 173 | jbe SHORT .BlockModeTransfersNotSupported
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| 174 | or WORD [di+DPT.wFlags], FLG_DPT_BLOCK_MODE_SUPPORTED
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| 175 | .BlockModeTransfersNotSupported:
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| 176 | ; Fall to .StoreDeviceSpecificParameters
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| 177 |
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| 178 | ;--------------------------------------------------------------------
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| 179 | ; .StoreDeviceSpecificParameters
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| 180 | ; Parameters:
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| 181 | ; DS:DI: Ptr to Disk Parameter Table
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| 182 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 183 | ; Returns:
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| 184 | ; Nothing
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| 185 | ; Corrupts registers:
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| 186 | ; AX, BX, CX, DX
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| 187 | ;--------------------------------------------------------------------
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| 188 | .StoreDeviceSpecificParameters:
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| 189 | call Device_FinalizeDPT
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| 190 | ; Fall to .StoreDriveNumberAndUpdateDriveCount
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| 191 |
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| 192 | ;--------------------------------------------------------------------
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| 193 | ; .StoreDriveNumberAndUpdateDriveCount
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| 194 | ; Parameters:
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| 195 | ; DS:DI: Ptr to Disk Parameter Table
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| 196 | ; ES:SI: Ptr to 512-byte ATA information read from the drive
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| 197 | ; ES: BDA Segment
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| 198 | ; Returns:
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| 199 | ; DL: Drive number for new drive
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| 200 | ; CF: Cleared if DPT parameters stored successfully
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| 201 | ; Set if any error
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| 202 | ; Corrupts registers:
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| 203 | ; Nothing
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| 204 | ;--------------------------------------------------------------------
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| 205 | .StoreDriveNumberAndUpdateDriveCount:
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| 206 | mov dl, [es:BDA.bHDCount]
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| 207 | or dl, 80h ; Set bit 7 since hard disk
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| 208 |
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| 209 | inc BYTE [RAMVARS.bDrvCnt] ; Increment drive count to RAMVARS
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| 210 | inc BYTE [es:BDA.bHDCount] ; Increment drive count to BDA
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| 211 |
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| 212 | cmp BYTE [RAMVARS.bFirstDrv], 0 ; First drive set?
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| 213 | ja SHORT .AllDone ; If so, return
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| 214 | mov [RAMVARS.bFirstDrv], dl ; Store first drive number
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| 215 | .AllDone:
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| 216 | clc
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| 217 | ret
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