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214 lines
7.1 KiB
Z80 Assembly
214 lines
7.1 KiB
Z80 Assembly
;::::::::::::::::::::::::::::::::::::::::::::::::**************************
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; Hard disk routines as implemented for ** Hardware Dependent **
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; SIMH Altair80 ** for exact interface **
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; D-X Designs Pty Ltd P112. **************************
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;--------------------------------------------------------------------------
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; This file uses modifications of the definitions in ICFG-xx to reflect
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; Physical and/or logical definitions for HBIOS drives. A controller type of
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; 8xH signifies IDE/ATA drives, in which case the Drive byte at HDRVx is:
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; 7 6 5 4 3 2 1 0
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; | | | | | | | +- Unit Number (0 = Master, 1 = Slave)
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; | | | | +-+-+--- (reserved)
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; | | | +--------- 1 = Active, 0 = Inactive
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; +-+-+----------- (reserved)
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; Additionally, the first byte of the Reduced Write Cylinder word is re-
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; defined to be the number of physical/logical Sectors-Per-Track.
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; These parameters are used to convert the Track & 16 Sector/Track format
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; assumed in the B/P Bios definitions for Hard Drives into Track/Sector/Head
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; Sector Number needed for IDE/ATA Data accesses. Direct driver IO routines
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; to Select (SELHD), Read (HDREAD) and Write (HDWRIT) are all included here.
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;--------------------------------------------------------------------------
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; 1.0 - 26 Aug 01 - Cleaned up source and included fixes from SCSI. HFB
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; 0.2 - 28 Jun 97 - Added Home Drive, Retry Disable bit handling. HFB
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; 0.1 - 25 Apr 97 - Initial Test Release HFB
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;***************************************************************************
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IF BANKED
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COMMON /BANK2/
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ELSE
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CSEG
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ENDIF
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;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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; Function 0 - Set User Data Area Adress for Direct Disk IO, Return
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; Number of Bytes in the driver Command Block (SCSI-"like")
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; For IDE, a minimum of 6 Bytes is needed (Comnd,Trk(2),Sctr,Head,Drive)
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; Enter: DE = Address of User Data Area
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; Exit : A = Number of bytes available in the Command Block
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; Uses : A,HL
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;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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HDVALS: CALL PANIC ; NOT IMPLEMENTED!!!!
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RET
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;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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; Function 1 - Set Drive bit Command Block from A
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; Enter: A = Drive Byte
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; Exit : A = Drive Bit in LSB (00/01H, for Master/Slave)
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; Uses : AF
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;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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HDSLCT: CALL PANIC ; NOT IMPLEMENTED!!!!
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RET
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;:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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; Function 2 - Direct SCSI driver. This routine performs the function
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; described by the command in the HD Command Block with Data area
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; addressed by DE. At the end of the function, 512 bytes of data are
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; transferred from the Bios IO Buffer to the Users Space set by Fcn 0.
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;
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; Enter: DE = Pointer to User Command Descriptor Block
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; HDCOMD contains pre-filled SCSI Command Block
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; A = 0 if No Data to be Written, FF if User-supplied data to write
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; Exit : H = Message Byte value
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; L = Status Byte value
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; A = Status byte, Flags set accordingly.
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; Uses : AF,BC,DE,HL
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; NOTE : Routine assumes the Command Block is properly configured for the
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; desired function and device. Errors in phasing result in program
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; exit and Warm Boot function, while Timeout returns 0FFH.
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; For external access, It assumes the user has used Functions 0 and 1 to
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; set the data transfer source/dest address and logical & physical drive.
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;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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HD_RW: CALL PANIC ; NOT IMPLEMENTED!!!!
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RET
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;========================================================================
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; Select Hard Disk (Unit 0/1, Master/Slave) < Internal Bios routine >
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SELHD: ; SET DEVICE
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; CALL PRTSTRD
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; DEFB '[SELHD]$'
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JP SETPARMS ; then set parameters for DPH/DPB
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;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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; Write to Hard Disk Drive < Internal BIOS Routine >
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; Writes from HSTBUF using HSTTRK and HSTSEC to build Block Number.
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; NOTE: This routine uses physical drive characteristics from ICFG-xx.
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HDWRIT:
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XOR A
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LD (HSTWRT),A ; Show no active writes pending
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JP HDSK_WRITE ; ..continue
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;::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
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; Read from Hard Disk Drive < Internal BIOS Routine >
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; Reads to HSTBUF using HSTTRK and HSTSEC to build Block Number.
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; NOTE: This routine uses physical drive characteristics from ICFG-xx.
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; The routine computes a sequential block number (as with SCSI) with
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; the algorithm; Trk * 16 + Sector, then computes Head, Sector and Track
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; using Physical characteristics (hdHds = Number_of_Heads,
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; hdSPT = Sectors_per_Track) according to the algorithm:
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;
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; Sector := (Block# MOD hdSPT)+1 (* Quotient1 := Block# DIV hdSPT *)
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; Head := Quotient1 MOD hdHds (* Quotient2 := Quotient1 DIV hdHds *)
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; Track := Quotient2
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HDREAD:
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JP HDSK_READ
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IF BANKED
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COMMON /B2RAM/
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ELSE
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DSEG
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ENDIF
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;======================= End of HARDIDE ===========================
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IF BANKED
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COMMON /BANK2/
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ELSE
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CSEG
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ENDIF
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;
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;==================================================================================================
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; HDSK DISK DRIVER
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;==================================================================================================
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;
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; IO PORT ADDRESSES
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;
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HDSK_IO EQU 0FDH
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;
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HDSK_CMDNONE EQU 0
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HDSK_CMDRESET EQU 1
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HDSK_CMDREAD EQU 2
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HDSK_CMDWRITE EQU 3
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HDSK_CMDPARAM EQU 4
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;
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; STATUS
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;
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HDSKRC_OK EQU 0
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;
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;
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;
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HDSK_READ:
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; CALL PRTSTRD
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; DEFB '[HDSK READ]$'
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LD B,13H ; $13 IS HBIOS DISK READ
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JR HDSK_RW
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;
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;
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;
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HDSK_WRITE:
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; CALL PRTSTRD
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; DEFB '[HDSK WRITE]$'
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LD B,14H ; $14 IS HBIOS DISK WRITE
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JR HDSK_RW
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;
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;
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;
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HDSK_RW:
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LD HL,(HSTDPH) ; GET ACTIVE DPH POINTER
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DEC HL ; ADJUST TO POINT TO UNIT NUMBER
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LD C,(HL) ; LOAD IT IN C FOR HBIOS CALL LATER
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PUSH BC ; SAVE FUNCTION AND DEVICE FOR LATER
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LD HL,(HSTTRK) ; GET TRACK VALUE
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LD A,L ; LSB OF TRACK TO A
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AND 0FH ; ISOLATE HEAD IN LOW 4 BITS
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LD D,A ; STUFF IT IN D
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LD A,(HSTSEC) ; GET SECTOR
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LD E,A ; STUFF IT IN E
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LD B,4 ; PREPARE TO SHIFT OUT 4 BIT HEAD VALUE
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HDSK_RW1:
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SRL H ; SHIFT ONE BIT OUT
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RR L ; ... OF HL
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DJNZ HDSK_RW1 ; DO ALL 4 BITS
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POP BC ; RECOVER FUNCTION AND DEVICE
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PUSH BC ; SAVE INCOMING FUNCTION, DEVICE/UNIT
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LD B,12H ; SETUP FOR NEW SEEK CALL
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CALL HBX_INVOKE ; DO IT
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POP BC ; RESTORE INCOMING FUNCTION, DEVICE/UNIT
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RET NZ ; ABORT IF SEEK RETURNED AN ERROR W/ ERROR IN A
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LD HL,(HB_DSKBUF) ; GET BUFFER ADDRESS
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LD DE,1 ; TRANSFER ONE SECTOR
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CALL HBX_INVOKE ; DO IT
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OR A ; SET FLAGS
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RET Z ; DONE IF NO ERROR
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OR 0FFH ; A=$FF TO SIGNAL ERROR
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RET ; AND DONE W/ ERROR
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;
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;==================================================================================================
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; HDSK DISK DRIVER - DATA
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;==================================================================================================
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;
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IF BANKED
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COMMON /B2RAM/
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ELSE
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DSEG
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ENDIF
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HDSK_PDN DEFS 1 ; PHYSICAL DEVICE
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