$title('MP/M II V2.0 User Number Assign/Display')
user:
do;

$include (copyrt.lit)
/*
  Revised:
    14 Sept 81  by Thomas Rolander
*/

  declare start label;
  declare jmp$to$start structure (
    jmp$instr byte,
    jmp$location address ) data  (
    0c3h,.start-3);

$include (proces.lit)


/*
    Common Literals
*/

  declare true literally '0FFFFH';
  declare false literally '0';
  declare forever literally 'while true';
  declare boolean literally 'byte';

  mon1:
    procedure (func,info) external;
      declare func byte;
      declare info address;
    end mon1;

  mon2:
    procedure (func,info) byte external;
      declare func byte;
      declare info address;
    end mon2;

  mon2a:
    procedure (func,info) address external;
      declare func byte;
      declare info address;
    end mon2a;

  declare xdos literally 'mon2';
  declare xdosa literally 'mon2a';

  declare fcb (1) byte external;

  print$buffer:
    procedure (bufferadr);
      declare bufferadr address;
      call mon1 (9,bufferadr);
    end print$buffer;

  who$user:
    procedure byte;
      return mon2 (32,0ffh);
    end who$user;

  terminate:
    procedure;
      call mon1 (143,0);
    end terminate;

  who$con:
    procedure byte;
      return xdos (153,0);
    end who$con;

  sys$dat$adr:
    procedure address;
      return xdosa (154,0);
    end sys$dat$adr;

  ASCII$to$int:
    procedure (string$adr) byte;
      declare string$adr address;
      declare string based string$adr (1) byte;

        if (string(0) := string(0) - '0') < 10 then
        do;
          if string(1) <> ' '
            then return string(0)*10 + (string(1)-'0');
            else return string(0);
        end;
        return 254;
    end ASCII$to$int;

  int$to$ASCII:
    procedure (string$adr);
      declare string$adr address;
      declare string based string$adr (1) byte;

        if string(0) < 10 then
        do;
          string(0) = string(0) + '0';
          string(1) = ' ';
        end;
        else
        do;
          string(1) = (string(0)-10) + '0';
          string(0) = '1';
        end;
    end int$to$ASCII;

  declare datapgadr address;
  declare datapg based datapgadr address;

  declare thread$root$adr address;
  declare thread$root based thread$root$adr address;

  declare TMPx (8) byte
    initial ('Tmpx    ');
  declare console byte at (.TMPx(3));

  declare msg1 (*) byte
    initial ('User Number = ');
  declare msg2 (5) byte
    initial ('xx',0dh,0ah,'$');
  declare user$nmb byte at (.msg2(0));

  declare pdadr address;
  declare pd based pdadr Process$descriptor;

  declare i byte;

  /*
     User Main Program
  */

  start:
    if fcb(1) = ' ' then
    /* displaying user number */
    do;
      user$nmb = who$user;
    end;
    else
    /* assigning user number */
    do;
      if (user$nmb := ASCII$to$int(.fcb(1))) < 16 then
      do;
        console = who$con + '0';
        datapgadr = sys$dat$adr + 252;
        datapgadr = datapg;
        thread$root$adr = datapgadr + 17;
        pdadr = thread$root;
        do while pdadr <> 0;
          i = 0;
          do while (i <> 8) and ((pd.name(i) and 7fh) = TMPx(i));
            i = i + 1;
          end;
          if i = 8 then
          do;
            pd.diskslct = (pd.diskslct and 0F0h) or user$nmb;
            pdadr = 0;
          end;
          else
          do;
            pdadr = pd.thread;
          end;
        end;
      end;
      else
      /* invalid user number entry */
      do;
        user$nmb = who$user;
        call print$buffer (.(
          'Invalid user number, ignored',0dh,0ah,'$'));
      end;
    end;
    call int$to$ASCII (.usernmb);
    call print$buffer (.msg1);
    call terminate;

end user;