195 lines
3.0 KiB
ArmAsm
195 lines
3.0 KiB
ArmAsm
;fastload8000.s
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org = $BE80 ; should be $BE80
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cout = $FDED ; character out sub
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crout = $FD8E ; CR out sub
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prbyte = $FDDA
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warm = $FF69 ; back to monitor
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tapein = $C060
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pointer = $06
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endbas = $80C
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;target = $1000
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target = $801
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chksum = $00
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inflate = $BA00
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inf_zp = $0
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start:
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.org endbas
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move:
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ldx #0
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move1: lda moved,x
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sta fast,x
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inx
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bne move1 ; move 256 bytes
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; ldx #0
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move2: lda moved+256,x
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sta fast+256,x
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inx
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bpl move2 ; only 128 bytes to move
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jmp fast
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moved:
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.org org
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fast:
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lda #<loadm
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ldy #>loadm
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jsr print
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lda ld_beg ; load begin LSB location
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sta store+1 ; store it
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lda ld_beg+1 ; load begin MSB location
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sta store+2 ; store it
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ldx #0 ; set X to 0
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lda #1 ; set A to 0
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nsync: bit tapein ; 4 cycles, sync bit ; first pulse
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bpl nsync ; 2 + 1 cycles
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main: ldy #0 ; 2 set Y to 0
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psync: bit tapein ;
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bmi psync
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ploop: iny ; 2 cycles
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bit tapein ; 4 cycles
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bpl ploop ; 2 +1 if branch, +1 if in another page
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; total ~9 cycles
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cpy #$40 ; 2 cycles if Y - $40 > 0 endcode (770Hz)
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bpl endcode ; 2(3)
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cpy #$15 ; 2 cycles if Y - $15 > 0 main (2000Hz)
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bpl main ; 2(3)
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cpy #$07 ; 2, if Y<, then clear carry, if Y>= set carry
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store: rol store+1,x ; 7, roll carry bit into store
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ldy #0 ; 2
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asl ; 2 A*=2
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bne main ; 2(3)
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lda #1 ; 2
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inx ; 2 cycles
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bne main ; 2(3)
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inc store+2 ; 6 cycles
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jmp main ; 3 cycles
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; 34 subtotal max
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; 36 subtotal max
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endcode:
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txa ; write end of file location + 1
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clc
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adc store+1
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sta store+1
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bcc endcheck ; LSB didn't roll over to zero
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inc store+2 ; did roll over to zero, inc MSB
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endcheck: ; check for match of expected length
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lda ld_end
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cmp store+1
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bne error
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lda ld_end+1
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cmp store+2
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bne error
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sumcheck:
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lda #0
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sta pointer
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lda ld_beg+1
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sta pointer+1
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lda #$ff ; init checksum
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ldy ld_beg
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sumloop:
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eor (pointer),y
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;last page?
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ldx pointer+1
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cpx ld_end+1
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beq last
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iny
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bne sumloop
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inc pointer+1
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bne sumloop
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last:
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iny
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cpy ld_end
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bcc sumloop
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; sty $01
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sta chksum
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lda chksum
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bne sumerror
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lda inf_flag ; if inf_flag = 0 runit
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beq runit
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inf:
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jsr crout
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lda #<infm
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ldy #>infm
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jsr print
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lda inf_src ;src lsb
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sta inf_zp+0
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lda inf_src+1 ;src msb
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sta inf_zp+1
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lda inf_dst ;dst lsb
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sta inf_zp+2
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lda inf_dst+1 ;dst msb
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sta inf_zp+3
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jsr inflate
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lda inf_end ;dst end +1 lsb
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cmp inf_zp+2
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bne error
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lda inf_end+1 ;dst end +1 msb
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cmp inf_zp+3
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bne error
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runit:
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lda warm_flag ; if warm_flag = 1 warm boot
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bne warmit
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jmp (runcode)
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warmit:
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jmp warm ; run it
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sumerror:
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jsr crout
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lda #<chkm
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ldy #>chkm
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jsr print
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error:
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lda #<errm
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ldy #>errm
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jsr print
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jmp warm
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print:
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sta pointer
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sty pointer+1
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ldy #0
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lda (pointer),y ; load initial char
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print1: ora #$80
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jsr cout
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iny
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lda (pointer),y
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bne print1
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rts
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chkm: .asciiz "CHKSUM "
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errm: .asciiz "ERROR"
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infm: .asciiz "INFLATING "
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ld_beg:
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.org *+2
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ld_end:
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.org *+2
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inf_src:
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.org *+2
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runcode:
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inf_dst:
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.org *+2
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inf_end:
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.org *+2
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inf_flag:
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.org *+1
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warm_flag:
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.org *+1
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loadm:
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;.asciiz "LOADING "
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end:
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