{ This program demonstrates how to call BDOS routines in a TURBO PASCAL
  program.  The program will print the names of the files on the default
  drive.

  Copyright (C) April 1984, Jack Y. Fong
  Commercial and publication rights are reserved.
  Copies made for personal use are permitted and encouraged.
}

PROGRAM JYFDIR;

TYPE
  { This is the File Control Block, I made it a record but it does not
    have to be a record.
  }
  FCB = RECORD
          AFILE: STRING[44];
          END;
  { This record defines the arguments for the BDOS and INTR functions
  }
  REGPACK = RECORD
          AX,BX,CX,DX,BP,SI,DI,DS,ES,FLAGS: INTEGER;
          END;

VAR
  { Allocate the variables.
  }
  FAT,DTA: FCB;
  REGS: REGPACK;

BEGIN
{ Initialize the File Control Block , this area will be used by DOS to
  hold the search information, once function 11 is executed do not
  make any changes to this area if function 12 is to be used. }
  FAT.AFILE := #255#0#0#0#0#0#0#0'???????????'#0#0#0#0 +
               '                     ';
{ Initialize the Disk Transfer Area, this is where DOS will put the
  FCB read in from the disk directory. It can be used by the program
  for a FCB. Confusing isn't it? }
  DTA.AFILE := #0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0+
               #0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0#0;
{ Pass the address of the DTA to the DOS . }
  REGS.DS := SEG(DTA.AFILE);  { Get segment value }
  REGS.DX := OFS(DTA.AFILE)+1; { Get the offset, add one since the first
                                 byte of a string stores the string length. }
{ Call MSDOS function 1AH to set the disk transfer address. }
  REGS.AX := 6656;     { Set AH to function 1AH, AL to 0 }
  MSDOS(REGS);
{ Set the registers to the address of the search FCB. }
  REGS.DS := SEG(FAT.AFILE);  { Get segment value }
  REGS.DX := OFS(FAT.AFILE)+1; { Get the offset, add one since the first
                                 byte of a string stores the string length. }
{ Call MSDOS function 11H to search for the first file entry }
  REGS.AX := 4352;     { Set AH to function 11H, AL to 0 }
  MSDOS(REGS);
  WRITE(#10#13' ',COPY(DTA.AFILE,9,8),'.',COPY(DTA.AFILE,17,3));
{ Get the rest of the file names. }
  REGS.AX := 4608;     { Set AH to function 12H, AL to 0 }
  WHILE REGS.AX = 4608 DO
    BEGIN
      MSDOS(REGS);
      WRITE(#10#13' ',COPY(DTA.AFILE,9,8),'.',COPY(DTA.AFILE,17,3));
    END;
END.AFILE,17,3));
    END;
END.