{ MS-System File Control Block, DOS Specific Version }

INTERFACE;  UNIT 
  FILKQQ (FCBFQQ, FILEMODES, SEQUENTIAL, TERMINAL, DIRECT,
          DEVICETYPE, CONSOLE, LDEVICE, DISK,
          DOSEXT, DOSFCB, FNLUQQ, SCTRLNTH);

CONST

  {$INCONST:MS_DOS  1 for MS-DOS, 0 for CP/M 80 or 86 }

  FNLUQQ = 21;          { length of a DOS filename }

  {$IF MS_DOS $THEN} 
  SCTRLNTH = 512;       { length of a disk sector }
  {$ELSE}
  SCTRLNTH = 128;       { length of a disk sector }
  {$END}

TYPE

DOSEXT = RECORD          { DOS file control block extension }

    PS  [0]: BYTE;       { boundary byte, not in extension }
    FG  [1]: BYTE;       { flag;  must be 255 in extension }
    XZ  [2]: ARRAY [0..4] OF BYTE;     { pad, internal use }
    AB  [7]: BYTE;       { internal use for attribute bits }
  END;

DOSFCB = RECORD           { DOS file control block (normal) }

    DR [00]: BYTE;        { drive numb, 0=default, 1=A etc }
    FN [01]: STRING (8);    { file name - eight characters }
    FT [09]: STRING (3);    { file extn - three characters }
    EX [12]: BYTE;        { current extent;  lo order byte }
    E2 [13]: BYTE;        { current extent;  hi order byte }
    S2 [14]: BYTE;        { size of sector;  lo order byte }
    RC [15]: BYTE;        { size of sector;  hi order byte }
    Z1 [16]: WORD;        { file size;  lo word;  readonly }
    Z2 [18]: WORD;        { file size;  hi word;  readonly }
    DA [20]: WORD;        { date;  bits:  DDDDDMMMMYYYYYYY }
    DN [22]: ARRAY [0..9] OF BYTE;      { reserved for DOS }
    CR [32]: BYTE;        { current sector (within extent) }
    RN [33]: WORD;        { direct sector number (lo word) }
    R2 [35]: BYTE;        { direct sector number (hi byte) }
    R3 [36]: BYTE;        { DSN hi byte iff sect size < 64 }
    PD [37]: BYTE;        { pad to word boundary;  not DOS }
  END;

DEVICETYPE = (CONSOLE, LDEVICE, DISK);    { physical device }

FILEMODES = (SEQUENTIAL, TERMINAL, DIRECT);   { access mode }

TYPE

FCBFQQ = RECORD     {byte offsets start every field comment}

{fields accessible by Pascal user as <file variable>.<field>}
TRAP: BOOLEAN;      {00 Pascal user trapping errors if true}
ERRS: WRD(0)..15;   {01 error status, set only by all units}
MODE: FILEMODES;    {02 user file mode;  not used in unit U}
MISC: BYTE;         {03 pad to word bound, special user use}

{fields shared by units F, V, U;  ERRC / ESTS are write-only}
ERRC: WORD;         {04 error code, error exists if nonzero}
                        {1000..1099:  set for unit U errors}
                        {1100..1199:  set for unit F errors}
                        {1200..1299:  set for unit V errors}
ESTS: WORD;         {06 error specific data usually from OS}
CMOD: FILEMODES;    {08 system file mode;  copied from MODE}

{fields set / used by units F and V, and read-only in unit U}
TXTF: BOOLEAN;      {09 true: formatted / ASCII / TEXT file}
                        {false: not formatted / binary file}
SIZE: WORD;         {10 record size set when file is opened}
                        {DIRECT: always fixed record length}
                        {others: max buffer variable length}
IERF: BOOLEAN;      {12 Unit U Incomplete End Of Record    }
                        {Kluge. Set false by opnuqq and    }
                        {pccuqq, and true by peruqq. Thus  }
                        {if true in wefuqq, it means that  }
                        {there is an incomplete line, and  }
                        {pccuqq should be called to flush  }
                        {it. Only applies to terminal files}
MISA: BYTE;         {13 Used to keep alignment with old misa}
OLDF: BOOLEAN;      {14 true: must exist before open; RESET}
                        {false: can create on open; REWRITE}
INPT: BOOLEAN;      {15 true: user is now reading from file}
                        {false: user is now writing to file}
RECL: WORD;         {16 DIRECT record number, lo order word}
RECH: WORD;         {18 DIRECT record number, hi order word}
USED: WORD;         {20 number bytes used in current record}

{field used internally by units F and V not needed by unit U}
LINK: ADR OF FCBFQQ;{22 DS offset address of next open file}

BADR: ADRMEM;       {24 ADR of buffer variable (end of FCB)}
TMPF: BOOLEAN;      {26 true if temp file;  delete on CLOSE}
FULL: BOOLEAN;      {27 buffer lazy evaluation status, TEXT}
UNFM: BOOLEAN;      {28 V: for unformatted binary file mode}
OPEN: BOOLEAN;      {29 file opened; RESET / REWRITE called}

{fields used internally by unit V not needed by units F or U}
FUNT: INTEGER;      {30 Unit V's unit number always above 0}
ENDF: BOOLEAN;      {32 last operation was the ENDFILE stmt}

{fields set / used by unit U, and read-only in units F and V}
REDY: BOOLEAN;      {33 buffer ready if true;  set by F / U}
BCNT: WORD;         {34 number of data bytes actually moved}
EORF: BOOLEAN;      {36 true if end of record read, written}
EOFF: BOOLEAN;      {37 end of file flag set after EOF read}

     {unit U (operating system) information starts here}
NAME: LSTRING (FNLUQQ); { 38 DOS filename (D:NNNNNNNN.XXX) }
DEVT: DEVICETYPE;       { 60 device type, accessed by file }
RDFC: BYTE;             { 61 function code, for device GET }
WRFC: BYTE;             { 62 function code, for device PUT }
CHNG: BOOLEAN;          { 63 true if sbuf data was changed }
SPTR: WORD;             { 64 index to current byte in sbuf }
LNSB: WORD;             { 66 number of valid bytes in sbuf }
DOSX: DOSEXT;           { 68 extend DOS file control block }
DOSF: DOSFCB;           { 76 normal DOS file control block }
IEOF: BOOLEAN;          {114 true if eoff is true next get }
FNER: BOOLEAN;          {115 true if pfnuqq filename error }
SBFL: BYTE;             {116 max textfile line len in sbuf }
SBFC: BYTE;             {117 number of chars, read to sbuf }
SBUF: ARRAY [WRD(0)..SCTRLNTH-1] OF BYTE; {118 sect buffer }
PMET: ARRAY [0..3] OF BYTE;     {118+sctrlnth reserved pad }
BUFF: CHAR;                     {122+sctrlnth (buffer var) }
     {end of section for unit U specific OS information}
END;
END;