[Coco] coco sub 64k memory modes

[Darren A]

On 8/4/09, Stephen Adolph <twospruces at gmail.com> wrote:

> Hi Darren,

> Really?  to me this implies that the 8k roms get copied to upper RAM

> on power up.  That appears to happen quickly.

>

> Neat.

>


Yes. The CoCo 3 has a 32K ROM.  The lower 16K contains mostly the same
code you would find in an Extended Basic CoCo 1/2.  During startup,
the ROM (along with the Disk Basic ROM if present) is copied to RAM
and then the CoCo 1/2 code is patched in a few places to call new
routines in Super Extended Color Basic.

Darren