SystemBeep splats memory on memory sizes like 208k

[jepler]

The ROM disassembly I'm following shows that the Mac Plus ROM is just always using the highest possible address for the audio buffer:

                      P_mBootBeep:
                      ; return address in A6
28A    4BF9 00EF E1FE            Lea.L     (VIA_Base), A5
290    41F9 003F FD00            Lea.L     ($3FFD00), A0   ; sound buffer base @sc
296    2848                      Move.L    A0, A4
298    40C5                      Move      SR, D5
29A    0245 0700                 And       #$700, D5

In nonstandard memory amounts like 208k, this ends up being somewhere within a repetition of the RAM.

Over in #14 I fixed this problem by patching at 0x292 with the correct sound buffer base. but you might want to fix this independent of taking #14.

[evansm7]

Ha, excellent find, thanks! Funny that this didn't do worse; I think I even ran SoundTrecker (which should then be writing to that buffer regularly) without crashes.
Maybe it was just "MacOS is about as stable as it usually is" ;-)
I might cherry-pick your fix for now, as there's a lot in #14. BBIAF...