| [3] | 1 | ; File name : AccessDPT.asm
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| 2 | ; Project name : IDE BIOS
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| 3 | ; Created date : 16.3.2010
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| 4 | ; Last update : 26.4.2010
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| 5 | ; Author : Tomi Tilli
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| 6 | ; Description : Functions for accessing DPT data.
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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 | ; Returns L-CHS values from DPT.
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| 13 | ;
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| 14 | ; AccessDPT_GetLCHSfromPCHS
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| 15 | ; Parameters:
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| 16 | ; DS:DI: Ptr to Disk Parameter Table
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| 17 | ; Returns:
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| 18 | ; AX: Number of L-CHS sectors per track
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| 19 | ; BX: Number of L-CHS cylinders
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| 20 | ; DX: Number of L-CHS heads
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| 21 | ; Corrupts registers:
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| 22 | ; Nothing
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| 23 | ;--------------------------------------------------------------------
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| 24 | ALIGN JUMP_ALIGN
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| 25 | AccessDPT_GetLCHSfromPCHS:
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| 26 | xchg ax, cx
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| 27 | mov cl, [di+DPT.bShLtoP] ; Load shift count
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| 28 | mov bx, [di+DPT.wPCyls] ; Load P-CHS cylinders
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| 29 | shr bx, cl ; Shift to L-CHS cylinders
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| 30 | xchg cx, ax
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| 31 | mov dx, [di+DPT.wLHeads] ; Load L-CHS heads
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| 32 | eMOVZX ax, BYTE [di+DPT.bPSect] ; Load Sectors per track
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| 33 | ret
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| 34 |
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| 35 |
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| 36 | ;--------------------------------------------------------------------
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| 37 | ; Tests IDEVARS flags for master or slave drive.
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| 38 | ;
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| 39 | ; AccessDPT_TestIdeVarsFlagsForMasterOrSlaveDrive
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| 40 | ; Parameters:
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| 41 | ; AX: Bitmask to test DRVPARAMS.wFlags
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| 42 | ; DS:DI: Ptr to Disk Parameter Table
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| 43 | ; Returns:
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| 44 | ; ZF: Set if tested bit was zero
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| 45 | ; Cleared if tested bit was non-zero
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| 46 | ; CF: 0
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| 47 | ; Corrupts registers:
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| 48 | ; BX
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| 49 | ;--------------------------------------------------------------------
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| 50 | ALIGN JUMP_ALIGN
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| 51 | AccessDPT_TestIdeVarsFlagsForMasterOrSlaveDrive:
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| 52 | call AccessDPT_GetPointerToDRVPARAMStoCSBX
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| 53 | test [cs:bx+DRVPARAMS.wFlags], ax
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| 54 | ret
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| 55 |
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| 56 | ;--------------------------------------------------------------------
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| 57 | ; Returns pointer to DRVPARAMS for master or slave drive.
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| 58 | ;
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| 59 | ; AccessDPT_GetPointerToDRVPARAMStoCSBX
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| 60 | ; Parameters:
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| 61 | ; DS:DI: Ptr to Disk Parameter Table
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| 62 | ; Returns:
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| 63 | ; CS:BX: Ptr to DRVPARAMS
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| 64 | ; Corrupts registers:
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| 65 | ; Nothing
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| 66 | ;--------------------------------------------------------------------
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| 67 | ALIGN JUMP_ALIGN
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| 68 | AccessDPT_GetPointerToDRVPARAMStoCSBX:
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| 69 | eMOVZX bx, [di+DPT.bIdeOff] ; CS:BX points to IDEVARS
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| 70 | test BYTE [di+DPT.bDrvSel], FLG_IDE_DRVHD_DRV
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| 71 | jnz SHORT .ReturnPointerToSlaveDRVPARAMS
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| 72 | add bx, BYTE IDEVARS.drvParamsMaster
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| 73 | ret
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| 74 | ALIGN JUMP_ALIGN
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| 75 | .ReturnPointerToSlaveDRVPARAMS:
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| 76 | add bx, BYTE IDEVARS.drvParamsSlave
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| 77 | ret
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