111 lines
2.3 KiB
Plaintext
111 lines
2.3 KiB
Plaintext
;license:MIT
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;(c) 2018 by 4am
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;TextFizzle routine (c) 2018 by qkumba
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;
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; Sound and animation effects
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;
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; Public functions
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; - SoftBell
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; - TextFizzle
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;
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;------------------------------------------------------------------------------
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; SoftBell
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;
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; in: none
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; out: all registers and flags preserved
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;------------------------------------------------------------------------------
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SoftBell
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php
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phx
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pha
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ldx #32
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- lda #2
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jsr WAIT
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bit SPEAKER
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lda #33
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jsr WAIT
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bit SPEAKER
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dex
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bne -
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pla
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plx
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plp
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rts
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;------------------------------------------------------------------------------
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; TextFizzle
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;
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; in: none
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; out: all registers and flags clobbered
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;------------------------------------------------------------------------------
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TextFizzle
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sta @src+1
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sta $c005
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ldy #0
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@copy
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lda TextFizzle,y
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sta TextFizzle,y
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iny
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bne @copy
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sta $c004
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; init RNG
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ldx #1
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stx @rndval1+1
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dex
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stx @rndval2+1
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@mainloop
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ldy @rndval1+1
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ldx @rndval2+1
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lsr @rndval2+1
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ror @rndval1+1
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bcc +
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; feedback polynomial forms #$402 for period of 2047
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lda @rndval1+1
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eor #2
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sta @rndval1+1
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lda @rndval2+1
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eor #4
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sta @rndval2+1
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; little hack to avoid missing offset zero
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; screen hole at $xxFF is missed instead
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+ tya
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eor #$ff
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sta $26
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and #$78
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cmp #$78
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beq @rndval2
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txa
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and #3
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ora #4
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sta $27
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ldy #0
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cpx #4
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bcc @src
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sta $c003
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sta $c055
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@src lda #$d1 ; SMC
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sta ($26),y
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sta $c002
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sta $c054
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lda #6
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jsr WAIT
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jsr AnyKeyOrClick
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bcs @exit
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@rndval2
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lda #0
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bne @mainloop
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@rndval1
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lda #0
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cmp #1
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bne @mainloop
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@exit
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rts
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