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https://github.com/a2stuff/prodos-path.git
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32 lines
897 B
ArmAsm
32 lines
897 B
ArmAsm
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;;; ============================================================
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;;; Bell
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;;;
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;;; From ProDOS 8 Technical Reference Manual 5.4:
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;;; "The standard Apple II "Air-raid" bell has been replaced with a
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;;; gentler tone. Use it to give users some aural feedback that
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;;; they are using a ProDOS program."
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.include "apple2.inc"
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.include "more_apple2.inc"
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.org $4000
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length := $06
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;;; Generate a nice little tone
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;;; Exits with Z-flag set (BEQ) for branching
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;;; Destroys the contents of the accumulator
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lda #32 ;duration of tone
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sta length
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bell1: lda #2 ;short delay...click
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jsr WAIT
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sta SPKR
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lda #32 ;long delay...click
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jsr WAIT
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sta SPKR
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dec length
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bne bell1 ;repeat length times
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clc
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rts
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