Date   : Mon, 25 Sep 2000 15:21:15 +0100
From   : "Rich Talbot-Watkins" <Richard_Watkins@...>
Subject: Re: Font Implosion / Explosions?

I've forgotten exactly what the behaviour of font implosion/explosion is now,
but I seem to remember it being relatively straightforward:

When the font is "imploded", character definitions for ASCII 128-159 are taken
from &C00..&CFF and these are echoed throughout 160-191, 192-223, 224-255.

IIRC, when the font is "exploded", page &C00..&CFF still provides 32 UDGs
(don't know which ones?), and the other 96 come from the old OSHWM (usually
&E00 for a tape-based system) and occupy three pages.  I'm fairly sure there's
a table somewhere in page 3 which defines which pages definitions for the
blocks of 32 characters are taken.  As far as I know, the OS doesn't do
anything clever and will simply use whatever is there initially.

Having said that, I'm not quite sure how exploding the main character set
(ASCII 32-127) works.  Normally, the character definitions (on OS1.20) live
between &C000..&C2FF - I'm not sure whether fully exploding the character set
will copy this memory into RAM or not.

I feel like I've maybe missed the point a bit though, feel free to call me a
pillock if this is the case :)

Cheers,
Rich :)
Rich Talbot-Watkins
Sony Computer Entertainment Europe, Cambridge.
Richard_Watkins@...