Add target for C64 :)

[EricCarrGH]

I wonder, since it is using ca65 asm, how difficult it would be to add a target/cfg file for C64, and have the basic integer-only interpreter working, and run a proof-of-concept program (control statements, vars, peek/poke).

I may try this.

@dmsc are there any major obstacles you can think of that make this difficult?

[dmsc]

Hi!

A basic program should not be difficult, after rewriting the basic I/O support.

But, there is one roadblock: currently FastBasic needs the address 0 to be filled with the value 0 - this is used to detect nul strings. The interpreter initializes pointers to 0, this means that a new declared string will read the address 0 to get the string length. This is a simple optimization, but ensures that you can do:

   DIM A$(10)
   ? A$(1),A$(2)

This will print two empty strings. If the address 0 has any other value, the above will print some random data.

I don't have much knowledge of C64, you could try porting some basic code and see if it works.

Have Fun!

[EricCarrGH]

Good to know, thank you. ZP address $0 and $1 are IO port registers for the 6510 (6502 variant) in the C64. Right now, the program could set $0 to 0 at start for a simple POC, and move the C64 screen memory (defaults to $400-$7E7) or change LBUFF, etc.

I'll do some exploring/testing when I get some time and post any updates.