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Sepp J Morris 31738079c4 Upload
Digital Research
2020-11-06 18:50:37 +01:00

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; BDOS symbols:
on EQU 0ffffh
off EQU 00000h
; Special 8086 symbols:
b equ byte ptr 0
w equ word ptr 0
; literal constants
enddir EQU 0ffffh ;end of directory
; file control block (fcb) constants
fcblen EQU 32 ;fcb length
empty EQU 0e5h ;empty directory entry
lstrec EQU 127 ;last record# in extent
recsiz EQU 128 ;record size
dirrec EQU recsiz/fcblen ;directory elts / record
dskshf EQU 2 ;log2(dirrec)
dskmsk EQU dirrec-1
fcbshf EQU 5 ;log2(fcblen)
maxext EQU 31 ;largest extent number
maxmod EQU 63 ;largest module number
fwfmsk EQU 80h ;file write flag is high
;order modnum
namlen EQU 15 ;name length
;lstfcb EQU fcblen-1
drv EQU 0 ;drive field
f1 EQU 1 ;file name byte 1 to 8
;f2 EQU 2
;f3 EQU 3
;f4 EQU 4
f5 EQU 5
;f6 EQU 6
f7 EQU 7
f8 EQU 8
; reserved file indicators
rofile EQU 9 ;t1' -> read/only file
sysfil EQU 10 ;t2' -> system file
ARCHIV EQU 11 ;t3' -> FILE HAS BEEN ARCHIVED
extnum EQU 12 ;extent number field
chksum EQU 13 ;unfilled bytes field
modnum EQU 14 ;data module number
reccnt EQU 15 ;record count field
dskmap EQU 16 ;disk map field
nxtrec EQU fcblen
ranrec EQU nxtrec+1 ;random record field (3 bytes)