c2t/asm/fastload8000.s
2014-11-23 17:26:22 -07:00

195 lines
3.0 KiB
ArmAsm

;fastload8000.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 ld_beg ; load begin LSB location
sta store+1 ; store it
lda ld_beg+1 ; load begin MSB location
sta store+2 ; store it
ldx #0 ; set X to 0
lda #1 ; set A to 0
nsync: bit tapein ; 4 cycles, sync bit ; first pulse
bpl nsync ; 2 + 1 cycles
main: ldy #0 ; 2 set Y to 0
psync: bit tapein ;
bmi psync
ploop: iny ; 2 cycles
bit tapein ; 4 cycles
bpl ploop ; 2 +1 if branch, +1 if in another page
; total ~9 cycles
cpy #$40 ; 2 cycles if Y - $40 > 0 endcode (770Hz)
bpl endcode ; 2(3)
cpy #$15 ; 2 cycles if Y - $15 > 0 main (2000Hz)
bpl main ; 2(3)
cpy #$07 ; 2, if Y<, then clear carry, if Y>= set carry
store: rol store+1,x ; 7, roll carry bit into store
ldy #0 ; 2
asl ; 2 A*=2
bne main ; 2(3)
lda #1 ; 2
inx ; 2 cycles
bne main ; 2(3)
inc store+2 ; 6 cycles
jmp main ; 3 cycles
; 34 subtotal max
; 36 subtotal max
endcode:
txa ; write end of file location + 1
clc
adc store+1
sta store+1
bcc endcheck ; LSB didn't roll over to zero
inc store+2 ; did roll over to zero, inc MSB
endcheck: ; check for match of expected length
lda ld_end
cmp store+1
bne error
lda ld_end+1
cmp store+2
bne error
sumcheck:
lda #0
sta pointer
lda ld_beg+1
sta pointer+1
lda #$ff ; init checksum
ldy ld_beg
sumloop:
eor (pointer),y
;last page?
ldx pointer+1
cpx ld_end+1
beq last
iny
bne sumloop
inc pointer+1
bne sumloop
last:
iny
cpy ld_end
bcc sumloop
; sty $01
sta chksum
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: