mirror of
https://github.com/Michaelangel007/c2t.git
synced 2024-10-08 16:54:29 +00:00
175 lines
3.7 KiB
ArmAsm
175 lines
3.7 KiB
ArmAsm
;diskload9600.s
|
|
|
|
org = $9000 ; should be $9000
|
|
cout = $FDED ; character out sub
|
|
crout = $FD8E ; CR out sub
|
|
prbyte = $FDDA ; print byte in hex
|
|
tapein = $C060 ; read tape interface
|
|
warm = $FF69 ; back to monitor
|
|
clear = $FC58 ; clear screen
|
|
endbas = $80C
|
|
target = $1000
|
|
|
|
; zero page parameters
|
|
|
|
begload = $00 ; begin load location LSB/MSB
|
|
endload = $02 ; end load location LSB/MSB
|
|
chksum = $04 ; checksum location
|
|
pointer = $0C ; LSB/MSB pointer
|
|
|
|
start:
|
|
.org endbas
|
|
move: ; end of BASIC, move code to readtape addr
|
|
ldx #0
|
|
move1:
|
|
lda moved,x
|
|
sta readtape,x
|
|
; lda moved+256,x
|
|
; sta readtape+256,x
|
|
inx
|
|
bne move1
|
|
phase1:
|
|
jsr crout ; print LOADING...
|
|
lda #<loadm
|
|
ldy #>loadm
|
|
jsr print
|
|
; diskload2 ORG
|
|
lda #$D0 ; store begin location LSB
|
|
sta begload
|
|
lda #$96 ; store begin location MSB
|
|
sta begload+1
|
|
; end of DOS + 1 for comparison
|
|
lda #$00 ; store end location LSB
|
|
sta endload
|
|
lda #$C0 ; store end location MSB
|
|
sta endload+1
|
|
|
|
jsr readtape ; get the code
|
|
jmp $9700 ; run it
|
|
loadm:
|
|
.byte "LOADING INSTA-DISK, ETA "
|
|
loadsec: ; 10 bytes for "XX SEC. ",$00
|
|
.byte 0,0,0,0,0,0,0,0,0,0
|
|
moved:
|
|
.org org ; $9000
|
|
readtape:
|
|
lda begload ; load begin LSB location
|
|
sta store+1 ; store it
|
|
lda begload+1 ; load begin MSB location
|
|
sta store+2 ; store it
|
|
|
|
lda #$ff ; init checksum
|
|
sta chksum
|
|
|
|
wait: bit tapein
|
|
bpl wait
|
|
waithi: bit tapein ; Wait for input to go high.
|
|
bmi waithi
|
|
pre: lda #1 ; Load sentinel bit
|
|
ldx #0 ; Clear data index
|
|
clc ; Clear carry (byte complete flag)
|
|
data: bcc waitlo ; Skip if byte not complete
|
|
store: sta target,x ; Store data byte
|
|
|
|
eor chksum ; compute checksum
|
|
sta chksum ; store checksum
|
|
|
|
lda #1 ; Re-load sentinel bit
|
|
waitlo: bit tapein ; Wait for input to go low
|
|
bpl waitlo
|
|
bcc poll9 ; Poll at +9 cycles if no store
|
|
inx ; Stored, so increment data index
|
|
bne poll13 ; Poll at +13 cycles if no carry
|
|
inc store+2 ; Increment data page
|
|
bne poll21 ; (always) poll at +21 cycles
|
|
|
|
one: sec ; one bit detected
|
|
rol ; shift it into A
|
|
jmp data ; and go handle data (C = sentinel)
|
|
|
|
zero: clc ; zero bit detected
|
|
rol ; shift it into A
|
|
jmp data ; and go handle data (C = sentinel)
|
|
|
|
poll9: bit tapein
|
|
bpl zero ; zero bit (short)(9-15 cycles)
|
|
poll13: bit tapein ; (2 cycles early if branched here)
|
|
bpl zero ; zero bit (15-21 cycles)
|
|
poll21: bit tapein
|
|
bpl zero ; zero bit (21-27 cycles)
|
|
bit tapein
|
|
bpl zero ; zero bit (27-33 cycles)
|
|
bit tapein
|
|
bpl zero ; zero bit (33-39 cycles)
|
|
bit tapein
|
|
bpl zero ; zero bit (39-45 cycles)
|
|
bit tapein
|
|
bpl zero ; zero bit (45-51 cycles)
|
|
bit tapein
|
|
bpl zero ; zero bit (51-57 cycles)
|
|
bit tapein
|
|
bpl zero ; one bit (57-63 cycles)
|
|
bit tapein
|
|
bpl one ; one bit (63-69 cycles)
|
|
bit tapein
|
|
bpl one ; one bit (69-75 cycles)
|
|
bit tapein
|
|
bpl one ; one bit (75-81 cycles)
|
|
bit tapein
|
|
bpl one ; one pulse (81-87 cycles)
|
|
bit tapein
|
|
bpl pre ; pre pulse (87-93 cycles)
|
|
bit tapein
|
|
bpl pre ; pre pulse (93-99 cycles)
|
|
bit tapein
|
|
bpl pre ; pre pulse (99-105 cycles)
|
|
|
|
; low freq signals end of data
|
|
endcode:
|
|
txa ; write end of file location + 1
|
|
clc
|
|
adc store+1
|
|
sta store+1
|
|
bcc endcheck ; LSB didn't roll over to zero
|
|
inc store+2 ; did roll over to zero, inc MSB
|
|
endcheck: ; check for match of expected length
|
|
lda endload
|
|
cmp store+1
|
|
bne error
|
|
lda endload+1
|
|
cmp store+2
|
|
bne error
|
|
jsr ok
|
|
sumcheck:
|
|
jsr crout
|
|
lda #<chkm
|
|
ldy #>chkm
|
|
jsr print
|
|
lda chksum
|
|
bne error
|
|
jmp ok ; return to caller
|
|
error:
|
|
lda #<errm
|
|
ldy #>errm
|
|
jsr print
|
|
jmp warm
|
|
ok:
|
|
lda #<okm
|
|
ldy #>okm
|
|
print:
|
|
sta pointer
|
|
sty pointer+1
|
|
ldy #0
|
|
lda (pointer),y ; load initial char
|
|
print1: ora #$80
|
|
jsr cout
|
|
iny
|
|
lda (pointer),y
|
|
bne print1
|
|
rts
|
|
|
|
chkm: .asciiz "CHKSUM "
|
|
okm: .asciiz "OK"
|
|
errm: .asciiz "ERROR"
|
|
end:
|