From c28a0bd5acc0a04acc457eb83962c4b1390d65d4 Mon Sep 17 00:00:00 2001 From: John Snape Date: Tue, 11 Apr 2023 13:48:26 -0700 Subject: [PATCH] Add files via upload --- source/new_bell.txt | 38 ++++++++++++++++++++++++++++++++++++++ 1 file changed, 38 insertions(+) create mode 100644 source/new_bell.txt diff --git a/source/new_bell.txt b/source/new_bell.txt new file mode 100644 index 0000000..6493f94 --- /dev/null +++ b/source/new_bell.txt @@ -0,0 +1,38 @@ + 1 * The standard Apple II "Air-raid" bell has + 2 * been replaced with a gentler tone. Use it + 3 * to give users some aural feedback that + 4 * they are using a ProDOS program. + 5 * The code for it follows. + 6 * + 7 SPKR EQU $C030 ;this clicks the speaker + 8 * +8000: 00 9 LENGTH DS 1 ;duration of tone + 10 * + 11 * This is the wait routine from the Monitor ROM. + 12 * +8001: 38 13 WAIT SEC +8002: 48 14 WAIT2 PHA +8003: E9 01 15 WAIT3 SBC #1 +8005: D0 FC 16 BNE WAIT3 +8007: 68 17 PLA +8008: E9 01 18 SBC #1 +800A: D0 F6 19 BNE WAIT2 +800C: 60 20 RTS + 21 * + 22 * Generate a nice little tone + 23 * Exits with Z-flag set (BEQ) for branching + 24 * Destroys the contents of the accumulator + 25 * +800D: A9 20 26 BELL LDA #$20 ;duration of tone +800F: 8D 00 80 27 STA LENGTH +8012: A9 02 28 BELL1 LDA #$2 ;short delay...click +8014: 20 01 80 29 JSR WAIT +8017: 8D 30 C0 30 STA SPKR +801A: A9 20 31 LDA #$20 ;long delay...click +801C: 20 01 80 32 JSR WAIT +801F: 8D 30 C0 33 STA SPKR +8022: CE 00 80 34 DEC LENGTH +8025: D0 EB 35 BNE BELL1 ;repeat LENGTH times +8027: 60 36 RTS + +--End assembly, 40 bytes, Errors: 0 \ No newline at end of file