;DF.BLK = 0

.MACRO E.VEN,?L1,?L2
  .IF DF DF.BLK
    .EMIT <.EVEN>
  .IFF
    L1:
      .EVEN
    L2:
      .=L1
    .IIF NE <L2-L1> .EMIT <.BYTE 0>
  .ENDC
.ENDM E.VEN

.MACRO B.LKW REPT=1
  .IF DF DF.BLK
    .EMIT <.BLKW REPT>
  .IFF
    .REPT REPT
      .EMIT <.WORD 0>
    .ENDR
  .ENDC
.ENDM B.LKW

.MACRO B.LKB REPT=1
  .IF DF DF.BLK
    .EMIT <.BLKB REPT>
  .IFF
    .REPT REPT
      .EMIT <.BYTE 0>
    .ENDR
  .ENDC
.ENDM B.LKB

;
; Low memory syscom variables
;

SY.DEV =: ^O<40>				; .BYTE = system device unit number
SY.COD =: ^O<41>				; .BYTE = LMD - low media code
SY.EXI =: ^O<42>				; .WORD = batch diagnostic managed exit path

;
; XXDP disk structure
;

;
; HOMBLK - XXDP MFD block
;
HBBLK. =: ^O<1>		; block 1 (for DL:)
HBBAS. =: ^O<1000>	; disk byte address

HB.NXT =: ^O<0>		;0  ; next block 	(always zero)
HB.UFD =: ^O<2> 	;   ; first UFD directory block
HB.DBC =: ^O<4>		;   ; directory block count
HB.MAP =: ^O<6>		;   ; first map block
HB.MBC =: ^O<10>	;   ; map block count
HB.MFD =: ^O<12>	;   ; MFD block (self-reference to block 1)
HB.VER =: ^O<14>	;   ; XXDP version (never seen used)
  DBXV2. =: ^O<1002>	;0  ; XXDP V2 version code
HB.TOT =: ^O<16>	;   ; total blocks
HB.RES =: ^O<20>	;   ; reserved blocks
HB.INT =: ^O<22>	;   ; interleave factor
HB.BOO =: ^O<24>	;0  ; boot block
HB.MON =: ^O<26>	;30 ; monitor block
HB.REF =: ^O<30>	;   ; MFD refreshed flag (not-0 = yes)
HBBBS. =: ^O<30>	    ; block size

;
; MFD (variety 2) block
;
MF.UFD =: ^O<2>		; First UFD block
MF.MON =: ^O<26>	; First block of monitor core image

H2.UFD =: ^O<0> 	; First UFD directory block
H2.DBC =: ^O<2>		; Directory block count
H2.MAP =: ^O<4>		; First map block
H2.MBC =: ^O<6>		; Map block count
H2.MFD =: ^O<10>	; MFD block (self-reference to block 1)
H2.VER =: ^O<12>	; XXDP version (never seen used)
  DBXV2. =: ^O<1002>	;   XXDP V2 version code
H2.TOT =: ^O<14>	; Total blocks
H2.RES =: ^O<16>	; Reserved blocks
H2.INT =: ^O<20>	; Interleave factor
H2.BOO =: ^O<22>	; Boot block
H2.MON =: ^O<24>	; Monitor block

;
; Directory entry
;
EN.FIL =: ^O<0>		;fil ; rad50 filename (0=>deleted)
EN.NAM =: ^O<2>		;nam ;
EN.TYP =: ^O<4>		;typ ;
EN.DAT =: ^O<6>		;    ; file date and contiguous flag
EN.ACT =: ^O<10>	;    ; ACT-11 use only, logical end. Not used in XXDP
EN.STA =: ^O<12>	;    ; start block
EN.LEN =: ^O<14>	;    ; length in blocks
EN.LST =: ^O<16>	;    ; last block in use
EN.FLG =: ^O<20>	;    ; flags (ACT-11 use only, logical 52. Not used in XXDP ??)
EN.BBS =: ^O<22>	;18. ;

UFDFLC =: ^D<510/EN.BBS> ; File entries count on UFD block
FILNMS =: ^D<9>		; Filename Size (without point) 

;
; EN.DAT - XXDP/DOSbatch date
;

; DATE = (YEAR*1000.) + day-in-year

ENDAT$ =: ^O<077777>	; date field mask
ENCTG$ =: ^O<100000>	; contiguous file flag