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18 lines
666 B
Plaintext
18 lines
666 B
Plaintext
Cometsong
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3-channel Mockingboard music with Lo-res graphics
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256-byte Intro for Apple II, Lovebyte 2022
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by Deater / dSr
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Fitting Mockingboard music in 256B was a challenge.
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Note: only plays music out the left stereo channel.
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Thanks to mA2E for the music.
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Thanks to qkumba for optimization help.
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This code does a lot of tricky things. It loads into the zero page
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(which makes memory use less) but the music data overflows into
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the low half of the stack (at $100 on 6502). The rest of the code
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avoids the use of the stack, so we can use the "PLA" (pull stack
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to accumulator) instruction to do an auto-increment load through
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the music. This trick saved 15+ bytes.
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