SCREEN.I

[Table of Contents]

The SCREEN.I include file resides on the Kyan Pascal 2.x Utilities Disk 1. It contains one procedure and one function:

Procedure ENABLE_SCREEN(Integer)
Function DISABLE_SCREEN Integer

Tuning off the Atari's Antic chip can speed up processing up to 30%.  For more information, see page 44 of Mapping The Atari Revised Edition.


PROCEDURE Enable_Screen(Num: Integer);
BEGIN
#A
 LDY #5      ;offset to Num
 LDA (_SP),Y ;...get LSB
 STA $22F    ;...store in SDMCTL (559)
#
END;(* Enable ANTIC procedure *)



FUNCTION Disable_Screen: Integer;
   BEGIN
       DISABLE_SCREEN:=0;
#A
 LDY #5      ;offset DISABLE_SCREEN
 LDA $22F    ;get SDMCTL (559)
 STA (_SP),Y ;...store it
 LDA #$00    ;zero out
 STA $22F    ;...SDMCTL
#
END;(* Disable ANTIC procedure *)