1 Oct
2007
1 Oct
'07
4:23 p.m.
I assume the grahpics chip is a TMS9918 or similar. In
which case you can
hang RAM off that, it doesn't appear in the main CPU memory map, but is
accessed thorugh some registes in said chip. I'd heard that on an
unexpanded 99/4A _all_ the RAM was on the video chip, your BASIC program
was stored in said RAM, and the interpretter (in ROM, in the CPU address
space) had to read your program via the video chip registers.
This (a) made the machine very slow and (b) made it impossble to program
in machine code.
I'd not say that is impossible, but I'm hardly pressed to believe that!
:oO