!to"c1551usb.prg",cbm
;
;
; 1551USB-Loader for tape buffer
;
; free mem at $1000 up to $ffff
;
; Compiler: ACME
p_lo = $d0 ; pointer lo
p_hi = $d1 ; pointer hi
blocks = $d2
t_lo = $d4
t_hi = $d5
; drive 9
; TIA 6523
porta = $fec0
; data port
portb = $fec1
; pb0: st0
; pb1: st1
portc = $fec2
; pc6: ack
; pc7: dav
ddra = $fec3
ddrb = $fec4
ddrc = $fec5
; start sys819
*=$0333
start:
sei
lda #%01000000
sta ddrc
and #$00
sta portc
sta ddra
sta ddrb
tay
tax
lda portb
cmp #$03
beq idle
notfound: jmp eot ; interface not found and quit
idle: lda portc
cmp #$80
bne idle
load:
lda porta ; get pointer lo
sta p_lo
lda #$40
sta portc ; set ack (pc6)
lda #$00
sta portc ; and delete ack
- lda portc
cmp #$80 ; wait for dav (pc7)
bne -
lda porta ; get pointer hi
sta p_hi
lda #$40
sta portc ; set ack (pc6)
asl
sta portc ; and delete ack
- lda portc
cmp #$80 ; wait for dav (pc7)
bne -
lda porta ; get blocks
sta blocks
lda #$40
sta portc ; set ack (pc6)
asl
sta portc ; and delete ack
- lda portc
cmp #$80 ; wait for dav (pc7)
bne -
lda porta ; get load-addr lo
sta t_lo
lda #$40
sta portc ; set ack (pc6)
asl
sta portc ; and delete ack
- lda portc
cmp #$80 ; wait for dav (pc7)
bne -
lda porta ; get load-addr hi
sta t_hi
lda #$40
sta portc ; set ack (pc6)
asl
sta portc ; and delete ack
- lda portc
cmp #$80 ; wait for dav (pc7)
bne -
; load prg
ldy #$00
loadprg:
-- lda porta ; get byte
sta (t_lo),y ; save
lda #$40
sta portc ; set ack (pc6)
asl
sta portc ; and delete ack
- lda portc
cmp #$80 ; wait for dav (pc7)
bne -
iny
bne --
inx
cpx blocks
beq eot
inc t_hi
bne --
eot: jmp end
end: cli
rtsLetzte Änderung: 2019-01-06 09:46:34
