prodos-drivers/ns.clock/ns.clock.system.s
Joshua Bell b621ac6a4d Add ROMX RTC driver, c/o Jeff Mazur.
This is a modified version of the ROMX Real-Time Clock driver. The changes include:

* Converting the source to ca65.

* Integrating with the driver installer framework.

* Adapting the driver to not modify page 2 beyond $220. The ROMX RTC
  firmware writes bytes to $2B0, and the the original driver placed
  temp code at $250. This can conflict with ProDOS applications that
  use page 2, so the driver was reworked to save/restore anything at
  at $2B0.

Other changes:

* Add a util/ source dir, and cricket/date, quit.system and
  pause.system there.

* Pull the "print current date" logic out of clock drivers into driver
  preamble.
2021-10-05 19:58:31 -07:00

294 lines
7.1 KiB
ArmAsm

;;; NS.CLOCK.SYSTEM
;;; Original by "CAP" 04/21/91
;;; http://www.apple2.org.za/gswv/a2zine/GS.WorldView/v1999/Oct/MISC/NSC.Disk.TXT
;;; Modification history available at:
;;; https://github.com/a2stuff/prodos-drivers
.setcpu "6502"
.linecont +
.feature string_escapes
.include "apple2.inc"
.include "apple2.mac"
.include "opcodes.inc"
.include "../inc/apple2.inc"
.include "../inc/macros.inc"
.include "../inc/prodos.inc"
;;; ************************************************************
.include "../inc/driver_preamble.inc"
;;; ************************************************************
;;; ============================================================
;;;
;;; Driver Installer
;;;
;;; ============================================================
.define PRODUCT "No-Slot Clock"
;;; ============================================================
;;; Ensure there is not a previous clock driver installed.
.proc maybe_install_driver
lda MACHID
and #$01 ; existing clock card?
beq detect_nsc ; nope, check for NSC
rts ; yes, done!
.endproc
;;; ------------------------------------------------------------
;;; Detect NSC. Scan slot ROMs and main ROMs. Try reading
;;; each location several times, and validate results before
;;; installing driver.
.proc detect_nsc
;; Preserve date/time
ldy #3 ; copy 4 bytes
: lda DATELO,y
sta saved,y
dey
bpl :-
;; Check slot ROMs
lda #>$CFFF
ldy #<$CFFF
sta ld4+2
sty ld4+1
sta st4+2
sty st4+1
lda #0
sta slot
lda #3 ; treat slot 0 as slot 3
sloop: ora #$C0 ; A=$Cs
sta st1+2
rloop: sta ld1+2
sta ld2+2
sta st2+2
lda #3 ; 3 tries - need valid results each time
sta tries
try: jsr driver ; try reading date/time
lda DATELO+1 ; check result
ror a
lda DATELO
rol a
rol a
rol a
rol a
and #$0F
beq next
cmp #13 ; month
bcs next
lda DATELO
and #$1F
beq next
cmp #32 ; day
bcs next
lda TIMELO+1
cmp #24 ; hours
bcs next
lda TIMELO
cmp #60 ; minutes
bcs next
dec tries
bne try
beq install_driver ; all tries look valid
next: inc slot
lda slot
cmp #8
bcc sloop ; next slot
bne not_found
;; Not found in slot ROM, try main ROMs ???
lda #>$C015
ldy #<$C015
sta ld4+2
sty ld4+1
ldy #$07
sta st1+2
sty st1+1
dey
sta st4+2
sty st4+1
lda #>$C800
bne rloop
;; Restore date/time
not_found:
ldy #3
: lda saved,y
sta DATELO,y
dey
bpl :-
;; Show failure message
jsr log_message
scrcode PRODUCT, " - Not Found."
.byte 0
rts
saved: .byte 0, 0, 0, 0
tries: .byte 3
slot: .byte 0
.endproc
;;; ------------------------------------------------------------
;;; Install NSC Driver. Copy into address at DATETIME vector,
;;; update the vector and update MACHID bits to signal a clock
;;; is present.
.proc install_driver
ptr := $A5
;; Update absolute addresses within driver
lda DATETIME+1
sta ptr
clc
adc #(unlock - driver - 1)
sta unlock_addr
lda DATETIME+2
sta ptr+1
adc #0
sta unlock_addr+1
;; Copy driver into appropriate bank
lda RWRAM1
lda RWRAM1
ldy #sizeof_driver-1
loop: lda driver,y
sta (ptr),y
dey
bpl loop
;; Set the "Recognizable Clock Card" bit
lda MACHID
ora #$01
sta MACHID
lda #OPC_JMP_abs
sta DATETIME
;; Invoke the driver to init the time
jsr DATETIME
lda ROMIN2
;; Display success message
jsr log_message
scrcode PRODUCT, " - "
.byte 0
;; Display the current date
jsr cout_date
rts ; done!
.endproc
;;; ============================================================
;;; NSC driver - modified as needed and copied into ProDOS
;;; ============================================================
driver:
php
sei
ld4: lda $CFFF ; self-modified
pha
st1: sta $C300 ; self-modified
ld1: lda $C304 ; self-modified
ldx #8
;; Unlock the NSC by bit-banging.
uloop:
unlock_addr := *+1
lda unlock-1,x ; self-modified
sec
ror a ; a bit at a time
: pha
lda #0
rol a
tay
ld2: lda $C300,y ; self-modified
pla
lsr a
bne :-
dex
bne uloop
;; Read 8 bytes * 8 bits of clock data into $200...$207
ldx #8
bloop: ldy #8
st2:
: lda $C304 ; self-modified
ror a
ror $01FF,x
dey
bne :-
lda $01FF,x ; got 8 bits
lsr a ; BCD to binary
lsr a ; shift out tens
lsr a
lsr a
tay
beq donebcd
lda $01FF,x
and #$0F ; mask out units
clc
: adc #10 ; and add tens as needed
dey
bne :-
sta $01FF,x
donebcd:
dex
bne bloop
;; Now $200...$207 is y/m/d/w/H/M/S/f
;; Update ProDOS date/time.
lda $0204 ; hour
sta TIMELO+1
lda $0205 ; minute
sta TIMELO
lda $0201 ; month
asl a
asl a
asl a
asl a
asl a
ora $0202 ; day
sta DATELO
lda $0200 ; year
rol a
sta DATELO+1
pla
bmi done
st4: sta $CFFF ; self-modified
done: plp
rts
unlock:
;; NSC unlock sequence
.byte $5C, $A3, $3A, $C5
.byte $5C, $A3, $3A, $C5
.byte $00
sizeof_driver := * - driver
.assert sizeof_driver <= 125, error, "Clock code must be <= 125 bytes"
;;; ************************************************************
.include "../inc/driver_postamble.inc"
;;; ************************************************************