2018-09-13 13:53:04 +00:00
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;license:MIT
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2021-12-14 19:02:51 +00:00
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;(c) 2017-2021 by qkumba/4am/John Brooks
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2018-09-13 13:53:04 +00:00
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2018-10-29 23:23:43 +00:00
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!cpu 6502
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2021-10-16 01:34:39 +00:00
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!to "build/FX.INDEXED/FIZZLE",plain
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2018-10-29 23:23:43 +00:00
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*=$6000
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2021-12-14 19:02:51 +00:00
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ldx #(end-start+1) ; copy LFSR code to zero page
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- ldy start-2, x
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sty $FE, x
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2018-09-13 13:53:04 +00:00
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dex
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2021-12-14 19:02:51 +00:00
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bne -
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jmp loop
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start
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!pseudopc 0 {
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;X=0
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;Y=0
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loop txa
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loop1 eor #$1B ; LFSR form 0x1B00 with period 8191
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wait dex
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bne wait
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tax
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loop2 txa
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2018-09-13 13:53:04 +00:00
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ora #$20
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2021-12-14 19:02:51 +00:00
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sta <dst+2
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2018-09-13 13:53:04 +00:00
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eor #$60
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2021-12-14 19:02:51 +00:00
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sta <src+2
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jsr src
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txa
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lsr
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tax
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tya
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ror
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tay
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bcc loop2
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bne loop
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bit $C000
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bmi exit
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txa
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bne loop1
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src lda $FD00, y ; SMC high byte
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dst sta $FD00, y ; SMC high byte
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exit rts
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}
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end
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