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diskii.s
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******************************************************************************************
*
* Disk II routines
* ========================================================================================
*
******************************************************************************************
* Disk II addresses:
PHASEOFF = $C080
PHASEON = $C081
MOTOROFF = $C088
MOTORON = $C089
DRV0EN = $C08A
DRV1EN = $C08B
Q6L = $C08C
Q7L = $C08E
*
* DISK II routines
*
ReadTrack
jsr PRINT
dfb _HOME,$8D,4,$88
asc "T="
dfb _PRBYTE
da DSTTRK
dfb 0
ldx SLOT16 ; Slot*16
lda MOTORON,x ; turn on drive
lda DRV0EN,x ; Drive #1
lda Q7L,x ; Q7 = Low and Q6 = Low => READ mode
lda Q6L,x
jsr ARMMOVE ; Go to our track (app init sets to 40, so first time this recalibrates)
; Fully read the track into buffer @ DATA
jsr SETUPDATA
ldy #0
:loop lda Q6L,x
bpl :loop
sta (DATA),y
iny
bne :loop
inc DATA+1
dec TEMP
bne :loop
lda MOTOROFF,x
rts
* Move the Disk II arm:
ARMMOVE LDA CURTRK
CMP DSTTRK
BNE :MOVE
:THERE LDX SLOT16 ; restore standard slot
RTS
:MOVE PHP
LDA #0
ROL ; direction from CMP
TAY
LDA CURTRK
LSR
TYA
ROL ; odd/even from track
ASL ; times 2
TAY
LDA ARMTABLE,Y
JSR ARMPHASE
LDA ARMTABLE+1,Y
JSR ARMPHASE
PLP
BCS :SUB1
:ADD1 INC CURTRK
BRA ARMMOVE
:SUB1 DEC CURTRK
BRA ARMMOVE
ARMPHASE ORA SLOT16
TAX
LDA PHASEON,X
LDA #$56
JSR DELAY
LDA PHASEOFF,X
RTS
* Phase table for moving arm
* Grouped by inward/outward movement, odd/even track
* To move the arm, two phases need to be triggered
ARMTABLE HEX 0204
HEX 0600
HEX 0604
HEX 0200
* Standard DOS 13-sector and 16-sector address/data field bytes
AddressFieldPrologue
hex D5AA96
AddressFieldEpilogue
hex DEAAEB
DataFieldPrologue
hex D5AAAD
DataFieldEpilogue
hex DEAAEB
* DOS 13-sector translate table
Translate13
hex ABADAEAFB5B6B7BABBBDBEBFD6D7DADB
hex DDDEDFEAEBEDEEEFF5F6F7FAFBFDFEFF
* DOS 16-sector translate table
Translate16
hex 96979A9B9D9E9FA6A7ABACADAEAFB2B3
hex B4B5B6B7B9BABBBCBDBEBFCBCDCECFD3
hex D6D7D9DADBDCDDDEDFE5E6E7E9EAEBEC
hex EDEEEFF2F3F4F5F6F7F9FAFBFCFDFEFF