405 lines
15 KiB
Plaintext
405 lines
15 KiB
Plaintext
.np
|
|
B700-B749 DOS 2nd stage boot loader.
|
|
Set RWTS parmlist to read DOS from disk.
|
|
Call Read/Write group of pages ($B793).
|
|
Create new stack.
|
|
Call SETVIC ($FE93) and SETKBD ($FE89).
|
|
Exit to DOS coldstart ($9D84).
|
|
.np
|
|
B74A-B78C Put DOS on tracks 0-2.
|
|
Set RWTS parmlist to write DOS to disk.
|
|
Call Read/Write group of pages ($B793).
|
|
Exit to caller.
|
|
.np
|
|
B78D-B792 Unused.
|
|
.np
|
|
B793-B7B4 Read/Write a group of pages.
|
|
call RWTS through external entry point ($B7B5).
|
|
Exit to caller.
|
|
.np
|
|
B7B5-B7C1 Disable interrupts and call RWTS.
|
|
.np
|
|
B7C2-B7D5 Set RWTS parameters for writing DOS.
|
|
.np
|
|
B7D6-B7DE Zero current buffer.
|
|
Zero 256 bytes pointed to by $42,$43.
|
|
Exit to caller.
|
|
.np
|
|
B7DF-B7E7 DOS 2nd stage boot loader parmlist.
|
|
B7DF Unused.
|
|
B7E0 Number of pages in 2nd DOS load.
|
|
B7E1 Number of sectors to read/write.
|
|
B7E2 Number of pages in 1st DOS load.
|
|
B7E3 INIT DOS page counter.
|
|
B7E4 Pointer to RWTS parmlist (2 bytes).
|
|
B7E6 Pointer to 1st stage boot location (2 bytes).
|
|
.np
|
|
B7E8-B7F8 RWTS parmlist.
|
|
B7E8 Table type. Must be $01.
|
|
B7E9 Slot number times 16.
|
|
B7EA Drive number ($01 or $02).
|
|
B7EB Volume number expected (0 matches any volume).
|
|
B7EC Track number ($00 to $22).
|
|
B7ED Sector number ($00 to $0F).
|
|
B7EE Pointer to Device Characteristics Table (2 bytes).
|
|
B7F0 Pointer to user data buffer for READ/WRITE (2 bytes).
|
|
B7F2 Unused.
|
|
B7F3 Byte count for partial sector (use $00 for 256).
|
|
B7F4 Command code: 0=SEEK, 1=READ, 2=WRITE, 4=FORMAT.
|
|
B7F5 Error code:(valid if carry set) $10=Write protect,
|
|
$20=Volume mismatch, $40=Drive error, $80=Read error.
|
|
B7F6 Volume number found.
|
|
B7F7 Slot number found.
|
|
B7F8 Drive number found.
|
|
.np
|
|
B7F9-B7FA Unused.
|
|
.np
|
|
B7FB-B7FE Device Characteristics Table (DCT).
|
|
B7FB Device type (should be $00).
|
|
B7FC Phases per track (should be $01).
|
|
B7FD Motor on time count (2 bytes - should be $EF, $D8).
|
|
.np
|
|
B7FF Unused.
|
|
.np
|
|
B800-B829 PRENIBBLE routine.
|
|
Converts 256 (8 bit) bytes to 342 (6 bit) "nibbles"
|
|
of the form 00XXXXXX.
|
|
Pointer to page to convert stored at $3E,$3F.
|
|
Data stored at primary and secondary buffers.
|
|
On entry: $3E,$3F contain pointer to user data.
|
|
On exit: A-reg:unknown
|
|
X-reg:$FF
|
|
Y-reg:$FF
|
|
Carry set
|
|
Exit to caller.
|
|
.np
|
|
B82A-B8B7 WRITE routine.
|
|
Writes prenibbilized data from primary and secondary
|
|
buffers to disk.
|
|
Calls Write a byte subroutine.
|
|
Writes 5 bytes autosync, starting data marks
|
|
($D5/$AA/$AD), 342 bytes data, one byte checksum, and
|
|
closing data marks ($DE/$AA/$EB).
|
|
Uses Write Translate Table ($ba29).
|
|
On entry: X-reg:Slot number times 16
|
|
On exit: Carry set if error
|
|
If no error:
|
|
A-reg:unknown
|
|
X-reg:unchanged
|
|
Y-reg:$00
|
|
Carry clear
|
|
Uses $26,$27,$678
|
|
Exit to caller.
|
|
.np
|
|
B8B8-B8C1 Write a byte subroutine.
|
|
Timing critical code used to write bytes at 32 cycle
|
|
intervals.
|
|
Exit to caller.
|
|
.np
|
|
B8C2-B8DB POSTNIBBLE routine.
|
|
Converts 342 (6 bit) "nibbles" of the form 00XXXXXX
|
|
to 256 (8 bit) bytes.
|
|
Nibbles stored at primary and secondary buffers.
|
|
Pointer to data page stored at $3E,$3F.
|
|
On entry: X-reg:Slot number times 16
|
|
$36,$37:pointer to user data
|
|
$26:byte count in secondary buffer ($00)
|
|
On exit: A-reg:unknown
|
|
X-reg:unknown
|
|
Y-reg:byte count in secondary buffer
|
|
Carry set
|
|
Exit to caller.
|
|
.np
|
|
B8DC-B943 READ routine.
|
|
Read a sector of data from disk and store it at
|
|
primary and secondary buffers. (First uses secondary
|
|
buffer high to low, then primary low to high)
|
|
On entry: X-reg:Slot times 16
|
|
Read mode (Q6L,Q7L)
|
|
On exit: Carry set if error.
|
|
If no error:
|
|
A-reg:$AA
|
|
X-reg:unchanged
|
|
Y-reg:$00
|
|
Carry clear
|
|
Uses $26
|
|
Exit to caller.
|
|
.np
|
|
B944-B99F RDADR routine.
|
|
Read an Address Field.
|
|
Reads starting address marks ($D5/$AA/$96), address
|
|
information (volume/track/sector/checksum), and
|
|
closing address marks ($DE/$AA).
|
|
On entry: X-reg:Slot number times 16
|
|
Read mode (Q6L,Q7L)
|
|
On exit: Carry set if error.
|
|
If no error:
|
|
A-reg:$AA
|
|
X-reg:unchanged
|
|
Y-reg:$00
|
|
Carry clear
|
|
$2F: Volume number found
|
|
$2E: Track number found
|
|
$2D: Sector number found
|
|
$2C: Checksum found
|
|
Uses $26,$27
|
|
Exit to caller.
|
|
.np
|
|
B9A0-B9FC SEEKABS routine.
|
|
Move disk arm to desired track.
|
|
Calls arm move delay subroutine ($B9FD).
|
|
On entry: X-reg:Slot number times 16
|
|
A-reg:Desired track (halftrack for single
|
|
phase disk).
|
|
$478:Current track.
|
|
On exit: A-reg:unknown
|
|
X-reg:unchanged
|
|
Y-reg:unknown
|
|
$2A and $478:Final track
|
|
$27:Prior track (if seek needed)
|
|
Uses: $26,$27,$2A,$2B
|
|
Exit to caller.
|
|
.np
|
|
B9FD-BA10 Arm move delay subroutine.
|
|
Delays a specified number of 100 Usec intervals.
|
|
On entry: A-reg:number of 100 Usec intervals.
|
|
$46,$47:Should contain motor on time count
|
|
($EF,$D8) from Device Characteristics Table
|
|
$478:Current track.
|
|
On exit: A-reg:$00
|
|
X-reg:$00
|
|
Y-reg:unchanged
|
|
Carry set
|
|
Exit to caller.
|
|
.np
|
|
BA11-BA28 Arm move delay table.
|
|
Contains values of 100 Usec intervals used during
|
|
Phase-on and Phase-off of stepper motor.
|
|
.np
|
|
BA29-BA68 Write Translate Table.
|
|
Contains 6 bit "nibbles" used to convert 8 bit bytes.
|
|
Values range from $96 to $FF.
|
|
Codes with more than one pair of adjacent zeros or
|
|
with no adjacent ones are excluded.
|
|
.np
|
|
BA69-BA95 Unused.
|
|
.np
|
|
BA96-BAFF Read Translate Table.
|
|
Contains 8 bit bytes used to convert 6 bit "nibbles".
|
|
Values range from $96 to $FF.
|
|
Codes with more than one pair of adjacent zeros or
|
|
with no adjacent ones are excluded.
|
|
.np
|
|
BB00-BBFF Primary Buffer.
|
|
BC00-BC55 Secondary Buffer.
|
|
.np
|
|
BC56-BCC3 Write Address Field during initialization.
|
|
Calls Write double byte subroutine.
|
|
Writes number of autosync bytes contained in Y-reg,
|
|
starting address marks ($D5/$AA/$96), address
|
|
information (volume/track/sector/checksum), closing
|
|
address marks ($DE/$AA/$EB).
|
|
On entry: X-reg:Slot number times 16
|
|
Y-reg:number of autosync to write
|
|
$3E: $AA
|
|
$3F: sector number
|
|
$41: volume number
|
|
$44: track number
|
|
On exit: A-reg:unknown
|
|
X-reg:unchanged
|
|
Y-reg:$00
|
|
Carry set
|
|
Exit to caller.
|
|
.np
|
|
BCC4-BCDE Write double byte subroutine.
|
|
Timing critical code that encodes address information
|
|
into even and odd bits and writes it at 32 cycle
|
|
intervals.
|
|
Exit to caller.
|
|
.np
|
|
BCDF-BCFF Unused.
|
|
.np
|
|
BD00-BD18 Main entry to RWTS.
|
|
Upon entry, store Y-reg and A-reg at $48,$49 as
|
|
pointers to the IOB.
|
|
Initialize maximum number of recals at 1 and seeks
|
|
at 4.
|
|
Check if the slot number has changed. If not,
|
|
branch to SAMESLOT at $BD34.
|
|
BD19-BD33 Update slot number in IOB and wait for old drive
|
|
to turn off.
|
|
BD34-BD53 SAMESLOT
|
|
Enter read mode and read with delays to see if disk
|
|
is spinning.
|
|
Save result of test and turn on motor just in case.
|
|
BD54-BD73 Move pointers in IOB to zero page for future use.
|
|
Device Characteristics Table pointer at $3C,$3D
|
|
and data buffer pointer at $3E,$3F.
|
|
Set up $47 (motor on time) with $D8 from DCT.
|
|
Check if the drive number has changed. If not,
|
|
branch to $BD74.
|
|
If so, change test results to show drive off.
|
|
BD74-BD8F Select appropriate drive and save drive being used
|
|
as high bit of $35. 1=drive 1, 0=drive 2.
|
|
Get test results. If drive was on, branch to $BD90.
|
|
Wait for capacitor to discharge using MSWAIT
|
|
subroutine at $BA00.
|
|
BD90-BDAA Get destination track and go to it using MYSEEK
|
|
subroutine at $BE5A.
|
|
Check test result again and if drive was on,
|
|
branch to TRYTRK at $BDAB.
|
|
Delay for motor to come up to speed.
|
|
BDAB-BDBB TRYTRK
|
|
Get command code.
|
|
If null, exit through ALLDONE at $BE46, turning drive
|
|
off and returning to caller.
|
|
If =4, branch to FORMDSK at $BE0D.
|
|
Otherwise, move low bit into carry (set=read,
|
|
clear=write) and save value on status reg.
|
|
If write operation, data is prenibbilized via a call
|
|
to PRENIB16 at $B800.
|
|
BDBC-BDEC Initialize maximum retries at 48 and read an
|
|
Address Field via RDADR16 at $B944.
|
|
If read was good, branch to RDRIGHT at $BDED.
|
|
If bad read, decrement retries, and, if still some
|
|
left try again. Else, prepare to recalibrate.
|
|
Decrement recal count. If no more, then indicate
|
|
drive error via DRVERR at $BE04.
|
|
Otherwise, reinitialize reseeks at 4 and recalibrate
|
|
arm. Move to desired track and try again.
|
|
BDED-BE03 RDRIGHT
|
|
Verify on correct track. If so branch to RTTRK
|
|
at $BE10.
|
|
If not, set correct track via SETTRK subroutine at
|
|
$BE95 and decrement reseek count.
|
|
If not zero then reseek track. If zero, then recal.
|
|
BE04-BE0A DRVERR
|
|
Clean up stack and status reg.
|
|
Load A-reg with $40 (drive error)
|
|
Goto HNDLERR at $BE48.
|
|
BE0B-BE0C Used to branch to ALLDONE at $BE46.
|
|
BE0D-BF0F FORMDSK
|
|
Jump to DSKFORM at $BEAF.
|
|
BE10-BE25 RTTRK
|
|
Check volume number found against volume number
|
|
wanted.
|
|
If no volume was specified, then no error.
|
|
If specified volume doesn't match, load A-reg with
|
|
$20 (volume mismatch error) and exit via HNDLERR
|
|
at $BE48.
|
|
BE26-BE45 CRCTVOL
|
|
Check to see if sector is correct.
|
|
Use ILFAV table at $BFB8 for software sector
|
|
interleaving.
|
|
If wrong sector, try again by branching back to
|
|
TRYADR at $BDC1.
|
|
If sector correct, find out what operation to do.
|
|
If write, branch to WRIT at $BE51.
|
|
Otherwise, read data via READ16 ($B8DC).
|
|
If read is good, then postnibble data via POSTNB16
|
|
($B8C2) and return to caller with no error.
|
|
BE46-BE47 ALLDONE
|
|
Skip over set carry instruction in HNDLERR.
|
|
BE48-BE50 HNDLERR
|
|
Set carry.
|
|
Store A-reg in IOB as return code.
|
|
Turn off motor.
|
|
Return to caller.
|
|
BE51-BE59 WRITE
|
|
Write a sector using WRITE16 ($B82A).
|
|
If the write was good, exit via ALLDONE ($BE46).
|
|
If bad write, load A-reg with $10 (write protect
|
|
error) and exit via HNDLERR ($BE48).
|
|
BE5A-BE8D MYSEEK
|
|
Provides necessary housekeeping before going to
|
|
SEEKABS routine.
|
|
Determines number of phases per track and stores
|
|
track information in appropriate slot dependent
|
|
location.
|
|
BE8E-BE94 XTOY routine.
|
|
Put slot in Y-reg by transferring X-reg divided
|
|
by 16 into Y-reg.
|
|
BE95-BEAE Set track number.
|
|
BEAF-BF0C INIT command handler
|
|
Provides setup for initializing a disk.
|
|
Get the desired volume number from the IOB.
|
|
Zero both the primary and secondary buffers.
|
|
Recalibrate the disk arm to track 0.
|
|
Set the number of sync bytes to be written between
|
|
sectors to $28 (40.).
|
|
Call TRACK WRITE routine for the actual formatting.
|
|
Allow 48 retries during initialization.
|
|
Double check that the first sector found is zero
|
|
after calling TRACK WRITE.
|
|
Increment the track number after successfully
|
|
formatting a track.
|
|
Loop back until 35 tracks are done.
|
|
BF0D-BF61 TRACK WRITE routine.
|
|
Start with sector zero.
|
|
Preceed it with 128 self-sync bytes.
|
|
Follow them with sectors 0 through 15 in sequence.
|
|
Set retry count for verifying the track at 48.
|
|
Fill the sector initilization map with positive
|
|
numbers.
|
|
Loop through a delay period to bypass most of the
|
|
initial self-sync bytes.
|
|
Read the first Address Field found.
|
|
If the read is good and sector zero was found,
|
|
enter the VERIFY TRACK routine.
|
|
Decrement the sync count by 2 (until it reaches 16
|
|
at which time it is decremented by 1).
|
|
If sync count is greater than or equal to 5, exit
|
|
via $BF71.
|
|
If not, set carry and return to caller.
|
|
BF62-BF87 VERIFY TRACK routine.
|
|
This routine reads all 16 sectors from the track that
|
|
was just formatted.
|
|
If an error occurs during the read of either the
|
|
Address Field or the Data Field, the number of
|
|
retries is decremented.
|
|
The routine continues reading until retries is zero.
|
|
Calls Sector Map routine ($BF88).
|
|
BF88-BFA7 Sector Map routine.
|
|
This routine marks the sector initialization map as
|
|
each sector is verified.
|
|
If an error occurs, the routine exits through $BF6C,
|
|
which decrements the number of retries and continues
|
|
if that value is greater than zero.
|
|
Upon completion of track zero, the sync count is
|
|
decremented by two if it is at least 16.
|
|
.np
|
|
BFA8-BFB7 Sector Initialization Map used to mark sectors as
|
|
they are initialized.
|
|
Contains a $30 prior to initialization of a track.
|
|
Value changed to $FF as each sector is completed.
|
|
.np
|
|
BFB8-BFC7 Sector Translate Table
|
|
Sector interleaving done with software.
|
|
.np
|
|
BFC8-BFD6 Patch area starts here.
|
|
Patch from $B741 to zero language card during boot.
|
|
Call SETVID ($FE93).
|
|
Unprotect Language Card (if present).
|
|
Store $00 at $E000.
|
|
Exit through SETKBD ($FE89) and DOS coldstart.
|
|
.np
|
|
BFD9-BFDB Unused.
|
|
.np
|
|
BFDC-BFE5 Patch called from $A0E2.
|
|
Set three additional defaults (Byte offset=0).
|
|
Return to caller.
|
|
.np
|
|
BFE6-BFEC Patch called from $A6D5.
|
|
Call $A75B to reset state and set warmstart flag.
|
|
Mark RUN not interrupted.
|
|
Return to caller.
|
|
.np
|
|
BFED-BFFF Patch called from $B377.
|
|
Call $AE7E to save file manager workarea.
|
|
Restore stack.
|
|
Close all open files ($A316).
|
|
Save stack again.
|
|
Exit through $B385 ("DISK FULL ERROR").
|
|
.br
|
|
.nx ch8 zpage use
|