30 Aug
2002
30 Aug
'02
6:13 a.m.
On Fri, 30 Aug 2002, Sellam Ismail wrote:
This is the same way the TransWarp accelerator works
on my Apple //e. You
press ESC when it's booting (the TransWarp has control of the system first
and fades in the "TransWarp" logo, during which time you can hit the key)
and it boots under regular speed (which is to say it hands control to the
mainboard 6502, whereas normally it takes control of the system with it's
on-board accelerated 6502).
OK, now I've never gotten to play with one of these. How exactly does it
hijack the system like this? Does it use some software trick to halt the
motherboard proc, or is there a bus line that lets it grab control, like
the /LOCK line* that's on an 80x86?
It'd be interesting to design a different replacement processor for the
system, maybe even some sort of ICE based that uses a (cheap, old) PC for
control.
* I have never used this in practice, but from reading about the processor
I believe this is what it does (allows a peripheral to steal the processor
bus).
-- Pat