collapseos/recipes/rc2014/basic/README.md

BASIC as a shell

This recipe demonstrate the replacement of the usual shell with the BASIC interpreter supplied in Collapse OS. To make things fun, we play with I/Os using RC2014's Digital I/O module.

Gathering parts

• Same parts as in the base recipe
• (Optional) RC2014's Digital I/O module

The Digital I/O module is only used in the example BASIC code. If you don't have the module, just use BASIC in another fashion.

Build the image

As usual, building os.bin is a matter of running make. Then, you can get that image to your EEPROM like you did in the base recipe.

Usage

Upon boot, you'll directy be in a BASIC prompt. See documentation in apps/basic/README.md for details.

For now, let's have some fun with the Digital I/O module. Type this:

> a=0
> 10 out 0 a
> 20 sleep 0xffff
> 30 a=a+1
> 40 goto 10
> run

You now have your Digital I/O lights doing a pretty dance, forever.

Looking at the glue code

If you look at the glue code, you'll see that it's very similar to the one in the base recipe, except that the shell includes have been replaced by the basic includes. Those includes have been copy/pasted from apps/basic/glue.asm and USER_RAMSTART has been replaced with STDIO_RAMEND so that BASIC's memory gets placed properly (that is, right after the kernel's memory).

Simple, isn't it?