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.. | ||
art | ||
lyrics | ||
music | ||
ascii_art_lz4.inc | ||
ascii_art.inc | ||
display_art.s | ||
display_lyrics.s | ||
duet.s | ||
ending.s | ||
GLADOS.HGR | ||
gr_offsets.s | ||
interrupt_handler.s | ||
lyrics.inc | ||
lz4_decode.s | ||
Makefile | ||
mockingboard_a.s | ||
objects_shape.inc | ||
README.still_alive | ||
sa_compressed.s | ||
sa_ed.s | ||
sa_mb.s | ||
SA.ED | ||
sa.edlyrics | ||
SA.KR4 | ||
SA.KRW | ||
still_alive.dsk | ||
still_alive.s | ||
title.bas | ||
TITLE.BAS | ||
TODO | ||
zp.inc |
Still Alive for the Apple II in roughly 16k By Deater (Vince Weaver) vince@deater.net BACKGROUND ~~~~~~~~~~ A few years back I implemented Valve's Portal in Applesoft BASIC. At the end it played Still Alive, but in horrible single-channel speaker beeps. I always wanted to have this sound better. So here is the end result. Still Alive in 6-Channel Mockingboard Sound in 80 column with cursor effects. Also in 40 column if your display can't handle 80 cols. And if you don't have a Mockingboard, then a simpler version using P. Lutus' Electric Duet 2-channel audio for the stock speaker. Fun fact: The letter 'Z' does not appear at all in the lyrics to the song. (Noticed when I had to edge comparison for uppercase off by one) Challenges: + 6-channel audio. Really its 4-channel (from a MOD file) but it actually does load and play audio on all 6 channels. + Fitting it all in 48k (want to avoid disk routines if can) + Printing the ASCII art (naive implementation takes longer than 50Hz) The ASCII art is roughly 7k. Thought of decompressing on the fly, but the LZ4 code is not re-entrant and the music is already decompressing on the fly. + Re-using the Lyrics for both the Mockingboard and Electric Duet versions. + Squeezing the compressed image into memory leaving room for all the code to be decompressed while leaving enough room that DOS still has room to load things. It's an *extremely* tight fit. + An odd issue where the 80col display would get corrupted if we set HIRES without explicitly setting LORES before doing PR#3 Goal: Binary fits in 16k (16384 bytes) note size (bytes) --------------------- ------ initial music player: 2078 add raw ascii art: 9142 add 3-channel music+lyrics,then slim a bit: 18787 initial 40 col support: 18864 have art loading properly 40col: 18910 lz4 encode the ascii art: 15529 revert because lz4 code not re-entrant: 18910 add 4-channel music (KR4): 20128 add cursor (a bit distracting): 20162 feature complete 40 col: 20180 intial 80 col support: 20191 80 col cursor: 20344 strip out some unneeded text printing: 19962 merge ED and MB code: 24993 properly select between versions: 25001 merge the ED and MB lyrics: 22828 80 column ED, wait for keypress+reboot at end: 22852 Crazy compression: Remove mockingboard detection: 16343 Memory Map: 0000: Zero Page 0100: Stack 0400: Text Page 0 (AUX 0400: 80 column text) 2000: HGR Page0 4000: HGR Page1 9600: DOS 37.5k C000: I/O Space D000: ROM FFFF: END Plan: Load compressed 16k image ($4000) at $5900 - $9900 We use MAXFILES 1 to give us some extra room just before DOS Decompress ENDING sequence at $1800 - $4000 (writes background to HGR graphics automatically) STILL_ALIVE: + $0800 - $5900 $2e2d of code $2282 of KR4 music *or* $0842 of ED music + Sound buffers ($3800, 14k) at $5e00 - $9600