This document describes standard ATALAN library for ATARI 8-bit platform. Some parts of this text require good knowledge of ATARI platform.
Application starts at $2000. When it ends, infine loop is performed. If you want to exit to DOS, execute DOS command at the end of application.
Variables are placed in zero page starting from address 128.
Printing strings is done using standard OS routine. When printing into arrays, it is supposed the array is displayed on screen and conversion to ATARI screen codes is performed.
It is possible to write interrupt routines directly in ATALAN. Compiler will create appropriate code to
VBI procedures are executed every frame (1/50s on PAL, 1/60 on NTSC). Defered VBI is used (consult ATARI ROM manual to understand what it means), so hardware registers must be used to change colors etc.
VBI procedure must be of type VBI. It takes no arguments.
To activate the interrupt, use on'vbi procedure.
cycle'color:vbi =
inc COLOR0(5)
COLBK = COLOR0(5) ;as we are using deferred VBI, we must copy the color to hardware register
on'vbi cycle'color
Wait for the end of current scan-line. (Performs sta WSYNC).