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6502bench/SourceGen/Examples/A2-Zippy/ZIPPY.S.txt
2018-09-28 10:05:11 -07:00

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********************************
* *
* ZipGS Control Program *
* By Andy McFadden *
* v1.0 11-Dec-91 *
* v1.1 14-Dec-91 *
* *
* Merlin assembler format *
* *
* This program is in the *
* public domain. *
* *
********************************
lst off
*
* This program uses the "lean & mean" approach to
* screen displays. Not much choice if we want to
* split the colors; we have to do all processing in
* the vbl period. Tough to modify, but hey, that's
* life in the big city.
*
XC ;allow 65c02 opcodes
XC ;allow 65c816 opcodes
*
* Zero page
*
tmp equ $00
ptr equ $02
ptr2 equ $04
*
* Firmware equates
*
kbd equ $c000
clr80col equ $c000 ;disable 80-column store
clr80vid equ $c00c ;disable 80-column hardware
clraltchar equ $c00e ;normal lc, flashing UC
clrkbd equ $c010
tbcolor equ $c022 ;low 4 are bkgnd, hi 4 are text
vertcnt equ $c02e ;vertical line counter
click equ $c030
cyareg equ $c036 ;controls speed, shadowing
rom equ $c082
*
* ZipGS equates
* (the choice of names is arbitrary and occasionally misleading)
*
reset equ $c058 ;R=nop, W=force reset
options equ $c059 ;R/W=bit options
lock equ $c05a ;R=get speed, W=lock/unlock
enable equ $c05b ;R=bit options, W=enable card
slotenab equ $c05c ;R/W=slot/speaker enable
speed equ $c05d ;R=bank, W=set speed
tag1 equ $c05e ;(stuff)
tag2 equ $c05f ;(stuff)
*
* Monitor equates
*
setreset equ $fb6f
bell equ $fbdd
home equ $fc58
wait equ $fca8
prbyte equ $fdda
setkbd equ $fe89
setvid equ $fe93
monitor equ $ff59
*
* Program
*
org $2000 ;this is a SYS file
jmp startup
dfb $ee ;ProDOS startup protocol
dfb $ee
dfb $41 ;65 bytes of space
stval dfb $00 ;we look here+1 (this is len)
ds $40
startup
lda rom
sta clr80col ;disable 80-col store
sta clr80vid ;disable 80-col hardware
sta clraltchar ;disable MouseText
lda clrkbd
jsr setkbd
jsr setvid
jsr home
* unlock the ZipGS registers
lda #$50
sta lock
sta lock
sta lock
sta lock
* check the startup protocol stuff
lda stval+1
beq :nostartup
ora #$80 ;set hi bit
cmp #$e0
blt :isupper1
sec
sbc #$20 ;convert to upper case
:isupper1
cmp #"E" ;enable?
bne :noten
stz enable
brl quit
:noten
cmp #"D" ;disable?
bne :notdi
stz lock
brl quit
:notdi ;unknown; ignore it
:nostartup
* initialize variables and the screen
lda lock
and #$f0
lsr A
lsr A
lsr A
lsr A
sta zip_lock
sta ent_lock
lda enable
sta zip_enb
sta ent_enb
lda slotenab
sta zip_slot
sta ent_slot
lda options
sta zip_opts
sta ent_opts
* enable the zip, and set it to max speed
stz enable ;enable
stz speed ;100%
* draw initial screen
lda tbcolor
sta cc1
sta cc2
jsr calc_speed
jsr draw_scrn
jsr draw_speed
jsr draw_opts
jsr draw_slot
:loop
jsr color_scrn
lda kbd
cmp #$e0
blt :isupper
sec
sbc #$20 ;convert to upper case
:isupper
cmp #"!" ;secret option
bne :notbang
lda zip_cyc+1
jsr prbyte
lda zip_cyc
jsr prbyte
bra :loop
:notbang
cmp #"D"
bne :notD
lda #$10
tsb zip_enb ;mark as disabled (1)
jsr draw_opts ;update options
bra :loop
:notD
cmp #"E"
bne :notE
lda #$10
trb zip_enb ;mark as enabled (0)
jsr draw_opts ;update options
bra :loop
:notE
cmp #$8a ;down arrow
beq :isslow
cmp #$88 ;left arrow
bne :notslow
:isslow lda zip_lock
inc A
cmp #$10 ;at max?
beq :loop ;yes, don't update
sta zip_lock
jsr draw_speed
bra :loop
:notslow
cmp #$8b ;up arrow
beq :isfast
cmp #$95 ;right arrow
bne :notfast
:isfast lda zip_lock
dec A
bmi :loop ;under 0, don't update
sta zip_lock
jsr draw_speed
bra :loop
:notfast
cmp #"B"
bne :notb
lda zip_opts
eor #$80
sta zip_opts
jsr draw_opts
bra :loop
:notb
cmp #"P"
bne :notp
lda zip_opts
eor #$40
sta zip_opts
jsr draw_opts
brl :loop
:notp
cmp #"A"
bne :nota
lda zip_opts
eor #$20
sta zip_opts
jsr draw_opts
brl :loop
:nota
cmp #"C"
bne :notc
lda zip_opts
eor #$10
sta zip_opts
jsr draw_opts
brl :loop
:notc
cmp #"F"
bne :notf
lda zip_opts
eor #$08
sta zip_opts
jsr draw_opts
brl :loop
:notf
cmp #"S"
bne :nots
lda zip_slot
eor #$01
sta zip_slot
jsr draw_slot
brl :loop
:nots
cmp #"1"
blt :notnum
cmp #"8"
bge :notnum
sec
sbc #"0" ;convert "1"-"7" to 1-7
tax
lda #$01
:sloop asl A ;want bits 1-7 in mask
dex
bne :sloop
sta tmp
lda zip_slot ;no toggle the slot status
eor tmp
sta zip_slot
jsr draw_slot
brl :loop
:notnum
cmp #$8d ;carriage return
bne :notret
jsr update_zip ;write stuff to zip
bra quit
:notret
cmp #$9b ;escape
bne :notesc
lda ent_enb ;restore entry values
sta zip_enb
lda ent_lock
sta zip_lock
lda ent_slot
sta zip_slot
lda ent_opts
sta zip_opts
jsr update_zip
bra quit
:notesc
* unknown key; make a tiny noise
* (don't forget, we're still in the vbl!)
lda click
lda #$01
jsr wait
lda click
brl :loop
*
* Quit to ProDOS
*
quit
lda #$a0
sta lock ;lock the registers
sta clrkbd
jsr home
jsr $bf00 ;execute MLI Quit call
dfb $65
dw Quit_p
Quit_p dfb $04
dfb 0,0,0,0,0,0,0,0
*
* Make changes
*
update_zip
lda zip_enb
and #$10 ;clear all but board disable
beq :enab
stz lock ;disable board
bra :cont
:enab stz enable ;enable board
:cont lda zip_lock ;get current speed
asl A ;shift it back
asl A
asl A
asl A
sta speed ;set speed
lda zip_opts
sta options
lda zip_slot
sta slotenab
rts
*
* Draw the initial screen
*
draw_scrn
* Embed the cache size in the static string
lda enable
and #$03 ;only want low two bits
asl A
tay ;two bytes/entry
lda :cache_tab,y
sta statline+12
iny
lda :cache_tab,y
sta statline+13
* draw the rest of the display
:drawit
lda #<:screen_data
sta ptr
lda #>:screen_data
sta ptr+1
:loop
lda (ptr)
sta ptr2
ldy #$01
lda (ptr),y
sta ptr2+1
beq :done
clc ;need Y-reg to start at 0
lda ptr
adc #$02
sta ptr
lda ptr+1
adc #$00
sta ptr+1
dey ;back to zero
:txtloop
lda (ptr),y
beq :txtdone
sta (ptr2),y
iny
bra :txtloop
:txtdone
iny ;advance ptr according to Y
tya ;(could have >256 bytes of data)
clc
adc ptr
sta ptr
lda ptr+1
adc #$00
sta ptr+1
bra :loop
:done
rts
* table of cache sizes
:cache_tab
asc " 8163264"
* initial screen data
:screen_data
dw $500+1 ;line 1, column 1
asc "ZipGS Control v1.1 By Andy McFadden",00
dw $680+1 ;line 5, column 1
statline asc "Your MHz/ K ZipGS is ",00
dr_enab equ $680+26
dw $780+5
asc "Slot 1:",00
dw $428+5
asc "Slot 2:",00
dw $4a8+5
asc "Slot 3:",00
dw $528+5
asc "Slot 4:",00
dw $780+21
asc "Slot 5:",00
dw $428+21
asc "Slot 6:",00
dw $4a8+21
asc "Slot 7:",00
dw $528+21
asc "Speakr:",00
dw $628+1
asc "Bank Switch LC cache:",00
dr_optb equ $628+23
dw $6a8+1
asc "Paddle Delay:",00
dr_optp equ $6a8+15
dw $6a8+21
asc "AppleTalk Dl:",00
dr_opta equ $6a8+35
dw $728+1
asc "Counter Del :",00
dr_optc equ $728+15
dw $728+21
asc "Follow CPS :",00
dr_optf equ $728+35
dw $4d0+3
asc "[ ]",00
dr_spdbar equ $4d0+4
dw $550+0
asc "________________________________________",00
dw $650+3 ;line 19, column 2
asc "E:Enable D:Disable Arrows:Speed",00
dw $6d0+3 ;line 20, column 2
asc "1-7:Slot S:Speaker BPACF:Option",00
dw $750+1 ;line 22, column 1
asc "Return stores and exits, Escape aborts",00
dw 0 ;end of list
*
* Draw speed-related info
* (percent, MHz, the speed bar, etc)
*
draw_speed
* insert percent of max into speed bar
lda zip_lock ;get current zip speed
asl A
asl A
asl A ;want it x8
tay
ldx #$00
:ploop lda :perc_tab,y
sta :speed+5,x
iny
inx
cpx #$06 ;6 chars each
blt :ploop
* print MHz
clc
xce
rep #$30 ;16 bits for both
mx %00
lda zip_mhz
and #$00ff ;ignore zip_mhz+1
xba ;mult * 256
sta tmp
lsr A
lsr A
lsr A
lsr A ;now only x16
sta ptr
lda zip_lock ;for each tick, drop 1/16th
and #$00ff
tax
inx
lda tmp
:subloop dex
beq :subdone ;don't subtract on 100%
sec
sbc ptr
bra :subloop
:subdone sta tmp ;now result = MHz * 256
ldx #$00a0
stx ptr ;leftmost char
and #$ff00
cmp #$0a00
blt :ok
sec
sbc #$0a00 ;subtract 10
ldx #"1"
stx ptr
:ok
clc
adc #"0"*256
ora ptr ;put space or 1 on left
sta :speed+18 ;(16-bit store)
* We got the whole number okay, now we need the
* fractional percentage. This burns a few cycles
* here... not pretty neither. What we want to do
* is convert 0-255 in the low byte of tmp to 0-99.
*
* We count 0-255 or less, incrementing twice every five,
* and subtracting one every 64. We get roughly 0-99.
* This is reasonably accurate, within +/- .02.
sep #$30 ;short acc, short xy
mx %11
sec ;return to emulation mode
xce
stz ptr
lda tmp ;exactly zero?
beq :iszero
ldy #$05 ;counting 5-1, from first
lda #$02
sta ptr ;result; start at two
lda #$00
sed ;how often do you see this?
:xloop
inc A
sta ptr+1 ;save counter
and #$3f ;divisible by 64?
bne :not64 ;nope
lda ptr
sec
sbc #$01 ;have to sbc for decimal mode
sta ptr
:not64
dey
bne :not5
lda ptr
clc
adc #$02 ;add two
sta ptr
ldy #$05 ;reset Y
:not5
lda ptr+1
cmp tmp ;the base 16 fraction
blt :xloop
cld ;very important!
:iszero
lda ptr ;now that we've got it,
tax ; store it.
and #$f0
lsr A
lsr A
lsr A
lsr A
clc
adc #"0"
sta :speed+21
txa
and #$0f
clc
adc #"0"
sta :speed+22
* draw the speed thermometer bar
lda #$10
sec
sbc zip_lock
tax ;now x has 1=6.25%, 10=100%
lda #$3f ;inverse mode AND mask
sta tmp ;AND mask
ldy #$00
:bloop
lda :speed,y
and tmp
sta dr_spdbar,y
iny
lda :speed,y
and tmp
sta dr_spdbar,y
iny
dex
bne :not0
lda #$ff ;X hit 0, so switch to normal
sta tmp
:not0 cpy #32 ;2 * 16 settings
blt :bloop
rts
* table of percentages, padded to 8 bytes each
:perc_tab
asc "100.00",0000
asc " 93.75",0000
asc " 87.50",0000
asc " 81.25",0000
asc " 75.00",0000
asc " 68.75",0000
asc " 62.50",0000
asc " 56.25",0000
asc " 50.00",0000
asc " 43.75",0000
asc " 37.50",0000
asc " 31.25",0000
asc " 25.00",0000
asc " 18.75",0000
asc " 12.50",0000
asc " 6.25",0000
* text for speed bar
:speed asc " xxx.xx% xx.xx MHZ ",00
*
* Draw options
* (enabled/disabled, external delay, etc)
*
draw_opts
* Start with board enable/disable. We do this one
* specially (print "enabled." instead of "enab").
* Easier to special case than do "right".
lda zip_enb
and #$10 ;want bit 4
beq :enb
lda #<:disabled_txt
sta ptr
lda #>:disabled_txt
sta ptr+1
bra :copy
:enb
lda #<:enabled_txt
sta ptr
lda #>:enabled_txt
sta ptr+1
:copy ldy #$00
:loop lda (ptr),y
beq :done
sta dr_enab,y
iny
bra :loop
:done
* now do each of the other five (bpacf)
lda #<dr_optb
sta ptr2
lda #>dr_optb
sta ptr2+1
lda #$80
jsr draw_enab
lda #<dr_optp
sta ptr2
lda #>dr_optp
sta ptr2+1
lda #$40
jsr draw_enab
lda #<dr_opta
sta ptr2
lda #>dr_opta
sta ptr2+1
lda #$20
jsr draw_enab
lda #<dr_optc
sta ptr2
lda #>dr_optc
sta ptr2+1
lda #$10
jsr draw_enab
lda #<dr_optf
sta ptr2
lda #>dr_optf
sta ptr2+1
lda #$08
jmp draw_enab
:disabled_txt
asc "disabled.",00
:enabled_txt
asc "enabled. ",00
* draw_opts subroutine
draw_enab
sta tmp ;save the mask
lda zip_opts ;get ZipGS options register
and tmp ;strip off the boring ones
bne :enb ;note: reverse of board enb
lda #<:disb_txt
sta ptr
lda #>:disb_txt
sta ptr+1
bra :copy
:enb
lda #<:enab_txt
sta ptr
lda #>:enab_txt
sta ptr+1
:copy ldy #$03
:loop lda (ptr),y
sta (ptr2),y
dey
bpl :loop
rts
:enab_txt asc "enab"
:disb_txt asc "disb"
*
* Draw slot info
*
draw_slot
ldx #$00
lda #$02 ;bit 2 = slot 1
:loop
sta tmp
lda :dr_slot,x
sta ptr
lda :dr_slot+1,x
sta ptr+1
lda zip_slot
and tmp
beq :disb
:enb lda #<:slow_txt
sta ptr2
lda #>:slow_txt
sta ptr2+1
bra :copy
:disb lda #<:fast_txt
sta ptr2
lda #>:fast_txt
sta ptr2+1
:copy ldy #$03
:cloop lda (ptr2),y
sta (ptr),y
dey
bpl :cloop
inx
inx
cpx #16
bge :done
lda tmp
asl A
bcc :loop
lda #$01 ;go back and do speaker delay
bra :loop
:done
rts
:dr_slot
dw $780+13 ;slot 1
dw $428+13
dw $4a8+13
dw $528+13 ;...
dw $780+29
dw $428+29
dw $4a8+29 ;slot 7
dw $528+29 ;speaker delay
:slow_txt asc "Slow"
:fast_txt asc "Fast"
*
* Calculate the max ZipGS speed
*
* I pulled this out of the source for the Zip S16
* program. I don't pretend to understand most of
* what this does. If you figure it out, send me a
* note...
*
calc_speed
clc
xce ;set native mode
rep #$30 ;16 bits
mx %00
stz :ascii ;clear the output buffer
stz :ascii+2
stz :ascii+4
stz :ascii+6
jsr getspeed ;do the actual speed calc
lda result ;result is decimal speed,
sta zip_cyc ; so convert to a decimal
pha ; string
pea $0000 ;hiaddr
pea :ascii ;loaddr
pea $0006 ;length
pea $0000 ;unsigned
ldx #$260b ;_Int2Dec
jsl $e10000
sep #$30 ;back to emulation mode
mx %11
sec
xce
* at this point, the buffer would contain "8005" for
* a speed of 8.005. This reduces it to "8.00".
ldy #$ff
:loop iny
lda :ascii,y ;seek to end
cmp #$00
bne :loop
lda #$20
sta :ascii-1,y ;kill last char
sta :ascii,y ;extend length by one
lda #$00
sta :ascii+2,y
dey ;now scoot the two decimal
ldx #$02 ; places over by one to make
:loop2 dey ; room for the period
lda :ascii,y
sta :ascii+1,y
dex
bne :loop2
lda #$2e ;stuff the decimal point in
sta :ascii,y
* now it's in a format which makes output nice. We
* want it in a numeric format too, so...
stz zip_mhz ;init to zero
lda :ascii-2,y ;10s column
ora #$80 ;set hi bit
sta statline+5 ;stuff it into static string
cmp #"1" ;is it a 1 (not expecting 25)
bne :lt10 ;yes, we're less than 10
lda #10
sta zip_mhz
:lt10
lda :ascii-1,y ;1s column
ora #$80 ;set hi bit
sta statline+6 ;stuff it
sec
sbc #"0" ;convert to numeric
clc
adc zip_mhz ;add to what we got already
sta zip_mhz
* (this was confusing... the speed bar assumes a max
* speed of x.00, and goes from there. If this showed
* 9.10 MHz and the speed bar said 9.00 MHz, it wouldn't
* make much sense. Easier to omit it than explain it.)
*
* lda :ascii+1,y ;0.1 column
* ora #$80
* sta statline+8
* lda :ascii+2,y :0.01 column
* ora #$80
* sta statline+9
rts
:ascii ds 10
*
* This is the meat of the speed calculator.
*
getspeed
mx %00 ;still 16 bits on entry
stz result
* I think this forces the card to cache us
ldy #$00ae
:loop lda :loop,y
dey
bne :loop
php
sei
sep #$30
mx %11 ;back to 8 bits
* set up the board and /gs firmware
lda cyareg
sta :save_cya
and #$7f ;set slow mode (!)
sta cyareg
* lda #$5a
* sta lock
* sta lock
* sta lock
* sta lock
lda #$00 ;FIX me
sta speed ;set 100% speed
sta enable ;enable board
lda options
sta :save_opts
and #$d7 ;disable ext del, CPS
sta options
* now we do something weird
lda #$80
sta tag1 ;this is a no-op?
lda #$00
sta tag1 ; (should clear cshupd)
* now we get down and get funky
rep #$30
mx %00
ldy #$0064
ldx #$0000
:loop1 ldal lock
bpl :loop1
:loop2 ldal lock
bmi :loop2
:loop3 ldal lock
bpl :loop3
:loop4 txa
ldx #$0005
:delay1 dex
bne :delay1
nop
nop
clc
adc #$0001
tax
ldal lock
bmi :loop4
dey
bne :loop3
txa
clc
adc #$0005
sta result ;ta-da!
sep #$20
mx %10 ;short a, long x
lda :save_opts
sta options
lda :save_cya
sta cyareg
* lda #$a5
* sta lock
rep #$20
plp
rts
:save_cya dfb $00
:save_opts dfb $00
result dw $0000
mx %11 ;short acc/regs after this
*
* Variable data stash
*
zip_mhz dfb $00 ;6-10 MHz
zip_cyc dw $0000 ;raw #of cycles counted
zip_enb dfb $00 ;what ENABLE should be
zip_lock dfb $00 ;what LOCK should look like (/16)
zip_slot dfb $00 ;what SLOTENAB should look like
zip_opts dfb $00 ;what OPTIONS should look like
ent_enb dfb $00 ;ENABLE on entry
ent_lock dfb $00 ;LOCK on entry
ent_slot dfb $00 ;SLOTENAB on entry
ent_opts dfb $00 ;OPTIONS on entry
********************************
* *
* Fancy text routines *
* (See FancyText demo for doc) *
* *
********************************
color_scrn
*
* Colors are:
* $00 - Black $08 - Brown
* $01 - Deep red $09 - Orange
* $02 - Deep blue $0a - Light gray
* $03 - Purple $0b - Pink
* $04 - Dark green $0c - Green
* $05 - Dark gray $0d - Yellow
* $06 - Medium blue $0e - Aquamarine
* $07 - Light blue $0f - White
*
* setup
lda #<color_data
sta ptr
lda #>color_data
sta ptr+1
lda tbcolor ;save current text/background color
pha
lda clrkbd ;clear keyboard status
* main loop
:main_loop
lda kbd ;key hit?
bmi :done ;yup, exit
ldy #$00
lda (ptr),y ;get count
beq :main_loop ;count == 0, so wait for key
tax
iny
* this is important part... shift bits around,
* wait for right time, and change.
:color_loop
lda (ptr),y ;get color
pha ;save for later
iny
lda (ptr),y ;get line
asl A ;mult x4
asl A ;8 lines per, but one bit in horicnt
clc
adc #$80 ;add 128, just because
iny
:wait_loop ;wait until scanner reaches line
cmp vertcnt ;4
bne :wait_loop ;3
pla ;3 found it, so change color
sta tbcolor ;4
dex ;all done with changes?
bne :color_loop ;nope, keep going
* done with colors, so branch back to top of main loop
bra :main_loop
* all done, so restore color and exit
:done
pla
sta tbcolor
rts
*
* Data
*
color_data
dfb $07 ;7 regions
cc1 dfb $00 ;to be set to current color
dfb 0 ;starting at line 0
dfb $0f ;black text/white bkgnd
dfb 1 ;starting at line 1
dfb $f6 ;white text/blue bkgnd
dfb 4 ;starting at line 4
dfb $d6 ;yellow text/blue bkgnd
dfb 17 ;starting at line 9
dfb $c6 ;green text/blue bkgnd
dfb 18 ;starting at line 18
dfb $f6 ;white text/blue bkgnd
dfb 19 ;starting at line 19
cc2 dfb $00 ;current color
dfb 23 ;line 23 (one up from bottom)
*
* Save the object file
*
lst on
typ $ff ;make it a SYS file
sav ZIPPY
lst off ;suppress symbol table
END ;ignore everything else
*
* Zip GS tech info
*
* I got this from David Empson, who get it from Zip Technologies.
*
* ZipChip GS Special Registers Ex ZIP Technology, 12 October 1990
*
* Registers must be unlocked before they can be accessed (see $C05A).
* Locking them will re-enable the annunciators.
*
* Writing to any I/O location $C058-$C05F (whether registers are locked or
* unlocked) will reset delay in progress.
*
* $C058 R No operation
*
* $C058 W Write any value to force poweron/reset bit to COLD (forces next
* reset to restore ZIP registers to defaults/switch settings).
*
* $C059 R/W 76543210
* *....... Bank Switch Language Card cache disable=1/enable=0?
* .*...... Paddle delay (5 ms) disable=0/enable=1 $C070/$C020
* ..*..... External delay (5 ms) disable=0/enable=1
* ...*.... Counter delay (5 ms) disable=0/enable=1 $C02E/$C07E
* ....*... CPS follow disable=0/enable=1
* .....*.. Last Reset warm? READ ONLY
* ......*. Hardware DMA READ ONLY
* .......* non-GS (0)/GS (1) READ ONLY
*
* $C05A R 76543210
* ****.... Current ZIP Speed, 0=100%, F=6.25%, in 6.25% increments
* ....1111
*
* $C05A W Write values as follows:
* $5x Unlock ZIP registers (must write 4 times)
* $Ax Lock ZIP registers
* other Force ZIP to follow system clock (i.e. disable card)
*
* $C05B R 76543210
* *....... 1msclk - clock with 1 ms period
* .*...... cshupd - Tag data at $C05F updated (read $C05F to reset)
* ..*..... Bank Switch Language Card cache (0), don't (1)
* ...*.... Board disable - 0=enabled, 1=disabled
* ....*... delay in effect (0=ZIP, 1=Slow)
* .....*.. rombank (0/1) - not in development version
* ......** Cache RAM size (00=8k, 01=16k, 10=32k, 11=64k)
*
* $C05B W Write any value to force ZIP to current speed (i.e. enable card)
*
* $C05C R/W 76543210
* *******. Slot 7-1 delay enable (all slots 52-54 ms)
* .......* Speaker delay enable (5 ms)
*
* $C05D R Current 65816 bank
*
* $C05D W 76543210
* ****.... Set ZIP speed, 0=100%, F=6.25%, in 6.25% increments
* ....**** Don't care
*
* $C05E R Read last Tag data written and force the next write to
* create a trash tag value.
*
* $C05E W No operation
*
* $C05F R Read last Tag data written and reset cshupd. Note: apparently
* any write to a ZIP register (unlocked) will clear cshupd, but cshupd says
* that this location must be read.
*
* $C05F W No operation