thaolt / katebasic

A Modern BASIC Programming language which support Chip8

katebasic

Originally, I called it c8basic, but wanted KateBASIC, sounds much better

Install depedencies

sudo apt install bnfc flex bison

Building

make

Kate Assembly language

Example

Draw user key input with blinking cursor

include 'c8.asm'
org 0x200

jmp	_start

_global:
	.cursor:	
		db	11111000b

_start:
	cls

	mov I, _global.cursor

	mov v1, 0 ; x
	mov v2, 6 ; y
	mov v3, 30 ; delay period 1/2 sec.
	mov v5, 0 ; x = 0 for draw character
	mov v6, 0 ; cursor need redraw?

	.loop:
		mov v4, 0 ; key scanner

		mov v0, dtm

		sne v0, 0
		jmp .draw_cursor

		.for:
		sknp v4
		jmp .keypress
		add v4, 1
		se v4, 16
		jmp .for

		.draw_cursor:
		sne v6, 0
		sne v0, 0
		drw v1, v2, 1
		se v6, 0
		mov v6, 0
		sne v0, 0
		mov dtm, v3
		jmp .loop

		.keypress:
		se vF, 1
		drw v1, v2, 1
		hex v4
		drw v1, v5, 5
		add v1, 5
		mov I, _global.cursor
		mov v6, 1
		jmp .draw_cursor

KateBasic Programming Language

Types

Currently there is only one type: byte

Comment

Line comment //

Block comment /* */

Declare variables

global flag = 1
global binnum as byte = %10010011
global max_height as byte = $10 // decimal 16

let a
let b as byte
let c as byte = 10
let d as byte[2] = { 50, 30 } // array declare and init

Sub and Functions

sub dosomething
  putc(0, 0, 5, $A) // draw number 0xA at top left of the display
endsub

function sum(a, b)
  let c = a + b
return c

Branching

if a > b then
  putc(10, 10, 1)
else
  putc(10, 10, 0)
endif

Looping

for i = 0 to 5
  putc( 0, i * 5, i )
endfor

for i = 0 to 10 step 2
  // do something
endfor

For loop has not step down yet (negative step)

Labels

if a > $100 then
  goto exit
endif

// do other thing

exit:
  halt