Disk Access Routines - Re-POST

[Mark Collins]

All,

Someone had recently sent me an email asking me to repost this information. I thought that I had already done this but didn't see it when I did a search. So here it is.

'X13 Disk Interrupt Vectors
%CMD_RESET_DISK				= 0
%CMD_INSTALLED				= 1
%CMD_STATUS				= 1
%CMD_READ_SECTOR			= 2
%CMD_WRITE_SECTOR			= 3
%CMD_VERIFY_SECTOR			= 4
%CMD_LOCK_UNLOCK			= 5
%CMD_EJECT_MEDIA			= 6
%CMD_EXTENDED_SEEK			= 7
%CMD_GET_PARAMETERS			= 8
%CMD_EXT_MEDIA_CHANGE			= 9
%CMD_SET_HARDWARE_CONFIG		= &HE


'X13 Command Vectors
'Set Hardware Configuration
%ENABLE_PREFETCH			= &H00
%DISABLE_PREFETCH			= &H01
%SET_MAX_PIO_MODE			= &H02
%SET_PIO_MODE_0				= &H03
%SET_DEFAULT_PIO_MODE			= &H04
%ENABLE_INT13_MAX_DMA_MODE		= &H05
%DISABLE_INT13_DMA_MODE			= &H06

'DOS Interrupt Call
%INT13		= &H13


TYPE X13Buffer
  PacketSize       AS BYTE     ' size of returned data structure
  Reserved         AS BYTE     'duh
  BlocksToTransfer AS WORD     'Number of sectors to transfer
  TransferBuffer   AS BYTE PTR 'Pointer to Transfer Buffer
  StartingBlock    AS QUAD     'Sector to transfer from
END TYPE	

FUNCTION XInt13(X13Command AS BYTE, BYVAL Buffer AS DWORD, Drive AS STRING, StartingSector AS QUAD, NumberOfSectors AS WORD) AS INTEGER
DIM DriveNum AS INTEGER
DIM Segment AS WORD
DIM Offset AS WORD

  DriveNum% = ASCII(UCASE$(Drive$)) - 64

  IF DriveNum% < 3 THEN
    DriveNum% = 3
  ELSE
    DriveNum% = DriveNum% + 125
  END IF

AXRegister% = X13Command? + &H40
SHIFT LEFT AXRegister%, 8

SELECT CASE X13Command?
  CASE %CMD_INSTALLED
    REG %BX,&H55AA

  CASE %CMD_READ_SECTOR, %CMD_WRITE_SECTOR
    IF (NumberOfSectors?? = 0) OR (NumberOfSectors?? = 1) THEN
      DIM SectorBuffer AS X13Buffer
    ELSE
      DIM SectorBuffer(NumberOfSectors - 1) AS X13Buffer
    END IF

    SectorBuffer.PacketSize?        = &H10
    SectorBuffer.Reserved?          = 0
    SectorBuffer.BlocksToTransfer?? = NumberOfSectors??
    SectorBuffer.TransferBuffer     = Buffer
    SectorBuffer.StartingBlock&&    = StartingSector&&

    REG %DS,VARSEG(SectorBuffer)
    REG %SI,VARPTR(SectorBuffer)

  CASE %CMD_GET_PARAMETERS
    Offset?? = BITS??(Buffer???)
    ROTATE RIGHT Buffer???, 16
    Segment?? = BITS??(Buffer???)

    REG %DS,Segment??
    REG %SI,Offset??

  CASE %CMD_SET_HARDWARE_CONFIG
    AXRegister% = X13Command + &H5E
    SHIFT LEFT AXRegister%, 16

  CASE ELSE
END SELECT

REG %DX,DriveNum%
REG %AX,AXRegister%

CALL INTERRUPT %INT13

CarryFlag% = REG(%FLAGS)
AXRegister% = REG(%AX)
BXRegister% = REG(%BX)
CarryFlag% = BIT(CarryFlag%, 0)
IF CarryFlag% THEN
  IF (X13Command = %CMD_INSTALLED) AND (BXRegister% <> &HAA55) THEN
    FUNCTION = %False
  ELSE
    IF INSTR(UCASE$(COMMAND$), "DEBUG") THEN
      SHIFT RIGHT AXRegister%, 8
      CALL DiskStatus(ByCopy Register%)
    END IF
  END IF
  FUNCTION = %False
END IF

FUNCTION = %True
END FUNCTION

SUB DiskStatus(StatusCode AS WORD)
PRINT
PRINT "Disk Operation StatusCode(";StatusCode;") ";
SELECT CASE StatusCode
  CASE &H00
    PRINT "returned successfully completed"
  CASE &H01
    PRINT "caused an invalid function in AH or an invlaid parameter"
  CASE &H02
    PRINT "returned address mark not found"
  CASE &H03
    PRINT "disk write-protected"
  CASE &H04
    PRINT "sector not found/read error"
  CASE &H05
    PRINT "reset failed (hard disk)"
  CASE &H06
    PRINT "disk changed (floppy or removable)"
  CASE &H07
    PRINT "drive paramter activity failed (hard disk)"
  CASE &H08
    PRINT "DMA overrun"
  CASE &H09
    PRINT "data boundary error (attempted DMA across 64K boundary or > 80h sectors"
  CASE &H0A
    PRINT "bad sector detected (hard disk)"
  CASE &H0B
    PRINT "bad track detected (hard disk)"
  CASE &H0C
    PRINT "unsupported track or invalid media"
  CASE &H0D
    PRINT "invalid number of sectors on format"
  CASE &H0E
    PRINT "control data address mark detected (hard disk)"
  CASE &H0F
    PRINT "DMA arbitration level out of range (hard disk)"
  CASE &H10
    PRINT "uncorrectable CRC or ECC error on read"
  CASE &H11
    PRINT "data ECC corrected (hard disk)"
  CASE &H20
    PRINT "controller failure"
  CASE &H31
    PRINT "no media in drive (IBM/MS Int13 extensions)"
  CASE &H40
    PRINT "seek failed"
  CASE &H80
    PRINT "timeout (not ready)"
  CASE &HAA
    PRINT "drive not ready (hard disk)"
  CASE &HB0
    PRINT "volume not locked in drive (XInt13)"
  CASE &HB1
    PRINT "volume locked in drive (XInt13)"
  CASE &HB2
    PRINT "volume not removable (XInt13)"
  CASE &HB3
    PRINT "volume in use (XInt13)"
  CASE &HB4
    PRINT "lock count exceeded (XInt13)"
  CASE &HB5
    PRINT "valid eject request failed (Xint13)"
  CASE &HBB
    PRINT "undefined error (hard disk)"
  CASE &HCC
    PRINT "write fault (hard disk)"
  CASE &HE0
    PRINT "status register error (hard disk)"
  CASE &HFF
    PRINT "sense operation failed (hard disk)"

END SELECT
END SUB

[This message has been edited by Mark Collins (edited January 24, 2003).]

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