CLOCK=0
MTRTM=1+1
DRVST=3+1
STEPS=5+1
COW=7
WORK=8+1
DTRCK=a
DSECT=b
CSECT=c
STAB=d+4
DRIVE=12
TRACK=13
NEXTS=14
SECTR=15
BUFPT=16+1
HDRPNT=18+1
FTNUM=1a
IP=1b+1
CNT=1d
IOB=1e
JOBNUM=1f

VIA_VB=40
VIA_DIN=41
VIA_VDDRB=42
VIA_T1LL=44
VIA_TIMER=45
VIA_ACR=4b
VIA_PCR=4c
VIA_IFR=4d
VIA_IER=4e

RIOT_DOUT=80
RIOT_EOUT=81
RIOT_PB=82
RIOT_DDRB=83

TICK=0400
DELAY=0401
CUTMT=0402
JOBS=0403+e
HDRS=0421+77

TAB1=0499+3
GAP1=049d
GAP2=049e
VERNUM=049f
ACTJOB=04a0

BUF0=0500

ANDB=ffeb
ANDC=ffed
ANDD=ffef
ANDE=fff1

START=fc47

RESET=fc00
IRQ=ff85


fc47 load # of jobs
L010=fc49
fc49 check if valid job, if so which drive
fc55 test motor status, turn on if not and set time for accel delay
fc6a test motor speed
fc74 test head status, if not moving branch to QUE
fc77 scan next job, if next job, branch to L010
END=fc7a
fc7a branch to start
;fc7c motor is on and head is still, if head is on right track, start
;fc7c processing by branching to GOTU, otherwise move to closest
;fc7c needed track: x=drive#, y=job#
QUE=fc7c
fc7c initialize to maximum distance + 1, and set y for max job#
fc83 init JOBS and HOBID by y offset
fc90 test if on right track
fc9e find closest seek

fcb1 decrement y loop for all jobs
fcb4 set up seek to closest track
FIN=fcce
fcce loop to search table again
TAB1=fcd0
fcd0 sectors/tracks table: .byt 17,18,20,21
ANDA=fcd4
fcd4 .byt $f3
TAB3=fcd5
fcd5 TAB3+1 = tracks: .byt $fc, 31, 25,18
fcd9 head is on desired track, set drive switch, # of sectors and bit density
GOTU=fcd9
fcdd set up for check of track zone
fce2 check for track zone
L032=fce2
fce8 set # sectors/track by results of L032
EXE=fd02
;fd02 Job Routine: execute: mode = 110 (E)
;fd02 check if execute, branch to EX if so, check if bump, branch to bump
;fd02 if so, jump seek
EX=fd0d
fd0d execute routing: get job#, calc buffer address, branch to it
BUMP=fd16
;fd16 Job Routine: bump the hub: more 100 (C)
;fd16 load drive #, accel to track, isolate drive, set head to phase "a"
;fd16 set head to max distance (#256-116), jmp DONE
WSECT=fd2d
fd2d decide which sector to service
fd43 check which job type, check track, drive
HPNT=fd8d
fd8d adjust header pointer: job.8 = hi byte of HDRS into HDRPNT
FSNUM=fda1
fda1 fix sector number for fake seek
READ=fdaa
;fdaa Job Routine: read a block: mode =000 (8)
;fdaa check if read or write, branch to WRITE if so
fdb1 get the bytes, store in (BUFPT),y, update checksum, jmp DEND
DSTRT=fdc3
fdc3 start reading data: init checksum, seach for header & start of data
WRITE=fdd6
;fdd6 Job Routine: write a block: mode =001 (9)
;fdd6 check if verify, branch to VRFY if so
;fdd6 check write protect, if ok L198, if no good, ER
L198=fde4
fde4 disable CB1 flag, get correct block
fdeb write sync mode, load fill code
fdfb reset port a flag, set 1st sync
fe05 store normal code mode in PCR, set 2nd sync, chksum
fe15 write block, write chksum, change job to verify, end
VRFY=fe3a
;fe3a Job Routine: verify a written block: mode=010 (A)
;fe3a read data
fe3d get byte and compare with contents of buffer, add up chksum
DEND=fe4e
fe4e end reading data, final chksum compare
fe59 check if decoding error: if not then DONE, else ER
fe61 set for verify error
ER=fe63
fe63 branch to error routing ERR
SEEK=fe65
;fe65  seek to determine next sector number
;fe65 init chksum, get block header
fe70 get a byte, store in STAB update chksum, branch again if more
fe8c load job# and type, test if seek, branch to ESEEK if so
fea6 check if id in (HDPTR),y = STAB,y error if not. continue loop, at end jmp WSECT
ESEEK=fe83
;fe83 Job Routine: seek: mode 011 (b)
feb9 get complete header from STAB,y into (HDRPNT),y
DONE=fec1
fec1 set for no error: #1
ERR=fec3
fec3 jump ERROR: error routine
CSERR=fec6
fec6 lda #9 (chksum error) branch to ERR
fecc lda#11 (mismatch), branch to ERR
SRCH=fece
fece search for specific block
fed2 compute checksum, set up for search for a sector
fedf jsr HEAD, set y for compare, every byte in hdr must be identical
fee4 compare to header loop, loop entire header
HEAD=fef3
fef3 seach for block head: .x=max# of trials
ERROR=fef9
;fef9 send error code
;fef9 #1: no error
;fef9 #2: can't find block head
;fef9 #3: no sync character
;fef9 #4: data block not present
;fef9 #5: checksum error
;fef9 #7: verify error
;fef9 #8: write with write protect on
;fef9 #9: checksum error in seeked header
;fef9 #10: data ran into next header
;fef9 #11: disk id mismatch
;fef9 #16: decoding error
ERR1=ffc7
ffc7 send job status, make motor stay longer, check job type
ff1f purge stack (#$3f)
ff25 get a byte, compare to start of header, branch if not equal to HEAD
WATCH=ff2d
;ff2d watch for sync characters
;ff2d bit PB, bvc L450: test if sync present, branch if yes
;ff2d bit IFR, bpl WATCH, test if byte present, loop until yes
;ff2d .x contains # of tests, branch to WATCH till .x=0
;ff2d bit PB, rts; test if sync present then return
SYNC=ff3f
ff3f hunt for sync character: set timer for 20ms limit
BYTE=ff52
ff52 get a byte
OFF=ff59
ff59 send two bytes, set for normal read mode
;ff63 change EOUT and PCR to send sync. 
;ff63 enable CB1, CA1, CB2 (IER=%10011010), get a byte. 
;ff63 reset VIA flags, get next byte, reset VIA, jmp BYTE (get next byte)
OUT=ff7c
ff7c byte to be sent is in .x
;ff85 CPU interrupt routine
ff85 interrupt for a few milliseconds: set next interrupt, reset timer
ff91 service motor: check if motor is on and stepping flag set
ffab service stepper motor
ffad check if on track, if not then L911. On track, clear stepping flag, check next stepper (jmp L920)
L911=ffba
ffba check direction - set out or step in 
ffc9 step in (+)
ffd0 step out (-)
ffd8 store new stepper position, test if DRVTST ready
ffe7 pop the stack of a and x and RTI


;fffc CPU vectors
*fffc WORD