; Forty columns or eighty, whichever the screen is not in.
;
; A machine wakes up in the forty column mode and CosmOS asks for eighty, because that is
; what its own output was written for. A game is the other way round: Snake on a forty column
; screen is the same board drawn twice the size, which is what a person sitting in front of
; it actually wants.
;
; ---- The smallest program this system can load ----
;
; Ten instructions and NO DATA AT ALL, which is not a curiosity: it is the shape that found
; a bug in the loader. Every program written for CosmOS until this one had something in its
; Data Segment, so the loader had never been asked to move a segment of no bytes - and a
; length of zero asks the memory controller for the whole 64K, which does not fit, which it
; refused, which stopped the machine in the middle of loading. On a terminal that printed a
; fault. Behind a window it looked exactly like a hang.
;
; So this is kept dataless on purpose. The two digits it prints are put in a register one at
; a time rather than being a string, which is the only reason it can say anything at all.
;
; Written by Anachronaut

#Include services.asm

#Program

  #Base 0x4000

start:
  INA 0x31                  ; Which mode the screen is in now.
  BRA modeWide              ; Nought is the forty column one, so go the other way.

  ; Anything else becomes forty, and that deliberately includes bitmap mode. A program that
  ; left the screen with no text on it left nowhere to print, so coming back to a mode that
  ; has characters in it is more use than refusing.
  RSTA
  OUTA 0x31
  INIA 0x34                 ; '4'
  BRI modeSay
modeWide:
  INIA 0x01
  OUTA 0x31
  INIA 0x38                 ; '8'
modeSay:
  OUTA 0x00
  INIA 0x30                 ; '0'
  OUTA 0x00
  INIA 0x0A
  OUTA 0x00
  RSTA
  SWI osExit