Challenge: implementing BASIC 7.0

Date: Fri, 07 Jun 2013 16:41:35 +0200
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Hallo allemaal,

I'm busy streamlining the disassembled code. During the proces I 
was reminded something: the BASIC code starts at $1C00. The range 
under $1C00 are variables and screen memory. That means we have a 
challenge: if we want to implement BASIC 7 in a C64 or other 
machine, some extra memory has to be found to store those extra 

For the C64 it means $1C00 - $0800 = $1400 bytes have to be found. 
With a bit of 'luck' not all variables are needed. If possible, the 
rest could fit into the $Cxxx area. But what if not?
Any other ideas are welcome

In my expanded VIC-20 I can replace block 5 with 8 KB of RAM. That 
should solve the proble here. If possible, I want to use the rest 
of this RAM for BASIC variavles, leaving me with more space for the 
actual program.

Do we have to worry about compatibilty? I can imagine there are 
programs around that use hard coded jumps or subroutines to access 
certain BASIC routines. I ran into such problems with the KCS Power 
cartridge with my 1541IDE project.
The most simple solution would be to leave the original BASIC code 
untouched and implement the 7 code in the other pages of the 
FlashRAM. Again, ideas are welcome.

About Mike's JiffyDOS idea: although the BASIC 7 ROM is 32 KB = 2 
FlashRAM 'pages', not all is BASIC. With a bit of luck both can be 
implented. Just an idea.

Kind regards / Met vriendelijke groet, Ruud Baltissen

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Received on 2013-06-07 15:00:04

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