import "io"

let buffer = vec(128);
let pos = 0;

let refill() be
{ let r = devctl(DC_TAPE_READ, 1, buffer);
  if r < 0 then
  { out("error %d from tape_read\n", r);
    finish } 
  pos := 0 }

let fgetc() be
{ let result;
  if pos >= 512 then
    refill();
  result := byte pos of buffer;
  pos +:= 1;
  resultis result }

let fopen(name) be
{ let r = devctl(DC_TAPE_LOAD, 1, name, 'R');
  if r < 0 then
  { out("error %d for load\n", r);
    finish } }

let fclose() be
{ devctl(DC_TAPE_UNLOAD, 1) }

let start() be
{ fopen("numbers.txt");
  while true do
  { let c = fgetc();
    out("the character was %c\n", c) }
  fclose(); }