| 1 | ; File name : AH8h_HParams.asm
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| 2 | ; Project name : IDE BIOS
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| 3 | ; Created date : 27.9.2007
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| 4 | ; Last update : 12.4.2010
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| 5 | ; Author : Tomi Tilli
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| 6 | ; Description : Int 13h function AH=8h, Read Disk Drive Parameters.
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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 | ; Int 13h function AH=8h, Read Disk Drive Parameters.
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| 13 | ;
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| 14 | ; AH8h_HandlerForReadDiskDriveParameters
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| 15 | ; Parameters:
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| 16 | ; AH: Bios function 8h
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| 17 | ; DL: Drive number
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| 18 | ; Parameters loaded by Int13h_Jump:
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| 19 | ; DS: RAMVARS segment
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| 20 | ; Returns:
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| 21 | ; CH: Maximum cylinder number, bits 7...0
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| 22 | ; CL: Bits 7...6: Cylinder number bits 9...8
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| 23 | ; Bits 5...0: Maximum sector number (1...63)
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| 24 | ; DH: Maximum head number (0...255)
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| 25 | ; DL: Number of drives
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| 26 | ; AH: Int 13h/40h floppy return status
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| 27 | ; CF: 0 if successfull, 1 if error
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| 28 | ; IF: 1
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| 29 | ; Corrupts registers:
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| 30 | ; Flags
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| 31 | ;--------------------------------------------------------------------
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| 32 | ALIGN JUMP_ALIGN
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| 33 | AH8h_HandlerForReadDiskDriveParameters:
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| 34 | push bx
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| 35 | call AH8h_GetDriveParameters
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| 36 | pop bx
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| 37 | jmp Int13h_ReturnWithoutSwappingDrives
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| 38 |
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| 39 |
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| 40 | ;--------------------------------------------------------------------
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| 41 | ; Returns L-CHS parameters for drive and total hard disk count.
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| 42 | ;
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| 43 | ; AH8h_GetDriveParameters
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| 44 | ; Parameters:
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| 45 | ; DL: Drive number
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| 46 | ; DS: RAMVARS segment
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| 47 | ; Returns:
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| 48 | ; CH: Maximum cylinder number, bits 7...0
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| 49 | ; CL: Bits 7...6: Cylinder number bits 9...8
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| 50 | ; Bits 5...0: Maximum sector number (1...63)
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| 51 | ; DH: Maximum head number (0...255)
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| 52 | ; DL: Number of drives
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| 53 | ; DS:DI: Ptr to DPT
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| 54 | ; AH: Int 13h/40h floppy return status
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| 55 | ; CF: 0 if successfull, 1 if error
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| 56 | ; Corrupts registers:
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| 57 | ; AL, BX
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| 58 | ;--------------------------------------------------------------------
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| 59 | ALIGN JUMP_ALIGN
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| 60 | AH8h_GetDriveParameters:
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| 61 | call FindDPT_ForDriveNumber
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| 62 | call AccessDPT_GetLCHSfromPCHS ; AX=sectors, BX=cylinders, DX=heads
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| 63 | call AH8h_ReserveCylinders
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| 64 | call AH8h_PackReturnValues
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| 65 | xor ax, ax ; Clear AH and CF
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| 66 | ret
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| 67 |
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| 68 |
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| 69 | ;--------------------------------------------------------------------
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| 70 | ; Reserves diagnostic cylinder if so configured.
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| 71 | ;
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| 72 | ; AH8h_ReserveCylinders
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| 73 | ; Parameters:
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| 74 | ; BX: Total number of L-CHS cylinders available
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| 75 | ; DS:DI: Ptr to DPT
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| 76 | ; Returns:
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| 77 | ; BX: Number of L-CHS cylinders available after reserving
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| 78 | ; Corrupts registers:
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| 79 | ; CX
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| 80 | ;--------------------------------------------------------------------
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| 81 | ALIGN JUMP_ALIGN
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| 82 | AH8h_ReserveCylinders:
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| 83 | test BYTE [cs:ROMVARS.wFlags], FLG_ROMVARS_MAXSIZE
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| 84 | jnz SHORT .Return
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| 85 | dec bx ; Reserve diagnostic cylinder
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| 86 | ALIGN JUMP_ALIGN
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| 87 | .Return:
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| 88 | ret
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| 89 |
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| 90 |
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| 91 | ;--------------------------------------------------------------------
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| 92 | ; Packs L-CHS values to INT 13h, AH=08h return values.
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| 93 | ;
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| 94 | ; AH8h_PackReturnValues
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| 95 | ; Parameters:
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| 96 | ; AX: Number of L-CHS sectors per track (1...63)
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| 97 | ; BX: Number of L-CHS cylinders available (1...1024)
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| 98 | ; DX: Number of L-CHS heads (1...256)
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| 99 | ; Returns:
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| 100 | ; CH: Maximum cylinder number, bits 7...0
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| 101 | ; CL: Bits 7...6: Cylinder number bits 9...8
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| 102 | ; Bits 5...0: Maximum sector number (1...63)
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| 103 | ; DH: Maximum head number (0...255)
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| 104 | ; DL: Number of drives
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| 105 | ; Corrupts registers:
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| 106 | ; AX, BX
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| 107 | ;--------------------------------------------------------------------
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| 108 | ALIGN JUMP_ALIGN
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| 109 | AH8h_PackReturnValues:
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| 110 | dec bx ; Cylinder count to last cylinder
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| 111 | dec dx ; Head count to max head number
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| 112 | mov dh, dl ; Max head number to DH
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| 113 | push ax
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| 114 | call RamVars_GetDriveCounts ; Hard disk count to CX
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| 115 | pop ax
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| 116 | mov dl, cl ; Hard disk count to DL
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| 117 | mov ch, bl ; Cylinder bits 7...0 to CH
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| 118 | mov cl, bh ; Cylinder bits 9...8 to CL
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| 119 | eROR_IM cl, 2 ; Cylinder bits 9...8 to CL bits 7...6
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| 120 | or cl, al ; Sectors per track to CL bits 5...0
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| 121 | ret
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