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.

[vitococl]

This could be interesting.

I'm sure it should be possible without too much effort, as I did the same for the Atari 5200 console. I had to write some I/O routines that the console did not have to simulate the A8's keyboard, display and joysticks, so most programs could be "compiled" to both systems without any change in the BASIC source code..

But I guess that special C64 features won't be mapped to current FastBasic syntax, like sprite management.