Slot ID
This page was last modified 14:20, 24 May 2020 by Rolandve. Based on work by Gdx and NYYRIKKI.

Slot ID (or slot address) is MSX-BIOS way to represent the slot and sub-slot location in a byte. The byte contains following info:

  • bit 0-1 = Primary slot number
  • bit 2-3 = Sub slot number (optional)
  • bit 4-6 = Unused
  • bit 7 = 1 if Slot is expanded

an example to interpret this from pascal is as follows:

procedure slotID(nValue:byte);
(** nValue is for example mem[$F344] **)
var
    num,num2: byte;
    exp : boolean;
begin;
        num:=nValue;
        num:= (num shl 6);
        num:= (num shr 6);
        if ((nValue and 128) = 128) then exp:=True else exp:=false;
        num2:=nValue;
        num2:=(num2 shl 4);
        num2:=(num2 shr 6);
        writeln('Slot-ID',num);
        writeln('subslot:',num2);
        writeln('expanded:',exp);
end;