c2t/asm/fastloadcd.s

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ArmAsm
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2014-11-24 00:26:22 +00:00
;fastloadcd.s
org = $BE80 ; should be $BE80
cout = $FDED ; character out sub
crout = $FD8E ; CR out sub
prbyte = $FDDA
warm = $FF69 ; back to monitor
tapein = $C060
pointer = $06
endbas = $80C
;target = $1000
target = $801
chksum = $00
inflate = $BA00
inf_zp = $0
start:
.org endbas
move:
ldx #0
move1: lda moved,x
sta fast,x
inx
bne move1 ; move 256 bytes
; ldx #0
move2: lda moved+256,x
sta fast+256,x
inx
bpl move2 ; only 128 bytes to move
jmp fast
moved:
.org org
fast:
lda #<loadm
ldy #>loadm
jsr print
lda #$ff
sta chksum
lda ld_beg ; setup point to target
sta store+1
lda ld_beg+1
sta store+2
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 store,x ; Store data byte
eor chksum
sta chksum
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 one ; one pulse (87-93 cycles)
bit tapein
bpl pre ; pre pulse (93-99 cycles)
bit tapein
bpl pre ; pre pulse (99-105 cycles)
bit tapein
bpl pre ; pre pulse (99-111 cycles)
endcode:
txa ; write end of file location + 1
clc
adc store+1
sta store+1
bcc endcheck
inc store+2
endcheck:
lda ld_end
cmp store+1
bne error
lda ld_end+1
cmp store+2
bne error
sumcheck:
lda chksum
bne sumerror
lda inf_flag ; if inf_flag = 0 runit
beq runit
inf:
jsr crout
lda #<infm
ldy #>infm
jsr print
lda inf_src ;src lsb
sta inf_zp+0
lda inf_src+1 ;src msb
sta inf_zp+1
lda inf_dst ;dst lsb
sta inf_zp+2
lda inf_dst+1 ;dst msb
sta inf_zp+3
jsr inflate
lda inf_end ;dst end +1 lsb
cmp inf_zp+2
bne error
lda inf_end+1 ;dst end +1 msb
cmp inf_zp+3
bne error
runit:
lda warm_flag ; if warm_flag = 1 warm boot
bne warmit
jmp (runcode)
warmit:
jmp warm ; run it
sumerror:
jsr crout
lda #<chkm
ldy #>chkm
jsr print
error:
lda #<errm
ldy #>errm
jsr print
jmp warm
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 "
errm: .asciiz "ERROR"
infm: .asciiz "INFLATING "
ld_beg:
.org *+2
ld_end:
.org *+2
inf_src:
.org *+2
runcode:
inf_dst:
.org *+2
inf_end:
.org *+2
inf_flag:
.org *+1
warm_flag:
.org *+1
loadm:
;.asciiz "LOADING "
end: