1. Multi-Speed Fractional Raster Clock (Refsp
/ CREFSP):
In wizball.asm and gameover.asm (lines 32, 110, 188, and
266) as well as
arkanoid.asm
(lines 57, 117, 172, and 237), DREFRESH waits for 4 PAL raster lines
per frame (200 Hz). At each raster point, 16-bit Refsp is added to
CREFSP. Whenever the high byte CREFSP+1 changes,
REFRESH
executes. Thus:
$0100
= 200 Hz, $0080 = 100 Hz, and $0040 = 50 Hz.
2. Bytecode Virtual Machine (vt0..vt2):
Each SID channel has a 16-bit sequence pointer (PC0..PC2
at $10..$15). Bytes < $C0 are note numbers (with bit
$60
selecting an immediate duration byte vs. datablock duration lookup), while bytes
>= $C0
(COM) dispatch through
vt0..vt2
for loops (For/Next), subroutine calls (Call/Ret/CT), instrument loads (FLoad/Vlm/Freq), filter sweeps (Filter/Master), and
inline 6502 machine code hooks (Code).
3. Real-Time $D418 Digi-Drums (arkadrum.asm
& gameover.asm):
While a 50 Hz VIC-II raster interrupt runs the 3 SID channels and the drum pattern
sequencer (DRUMS), the foreground MAIN loop continuously
calls PLEY, streaming either real-time algorithmic 4-bit waveforms (arkadrum.asm) or packed 4-bit PCM rock drum samples (ROCKBASS,
ROCKSNARE, ROCKCOWBELL in gameover.asm) to
the 6581 master volume DAC at $D418.
4. Rambo II Secret Morse Code (rambload.asm):
One second into the loader music, Channel 0 executes
DFB Code: DFW STARTMC, patching
MUS+1
to MCREFR. Voice 1 transmits the hidden string at Secret
(BILL BARNA, DAVID COLLIER, MARTIN GALWAY, TONY POMFRET, STEVE WAHID)
in 516 Hz (PAL) / 535 Hz (NTSC) Morse code using the bit-packed lookup table
CodeTab
before restoring REFRESH.