Function No.
Explanation
Entry Parameter
Returned value
Function No.
Explanation
Entry Parameter Return Parameter
15
This function opens a file.
C:
OFH
A:
Directory code
DE:
FCB
address
OFFH
when the file cannot be
26
This function changes the DMA
C:
IAH
address.
DE:
DMA ad-
Positions 1
found.
dress
through 14 must
This function fills the
FCB
in
contain the
the
main memory with
the
name of the file
contents of the corresponding
27
This function
returns the
base
C:
IBH
HL:
ALLOC address
address of the allocation vector.
to
be
opened.
FCB
in
the directory stored on
28
This function sets the read only
C:
1CH
the disk.
attribute
for
the
currently
16
This function closes a file.
C:
10H
A:
Directory code
logged-in drive
DE:
FCB
address
OFFH
when the file cannot
be
29
This function
returns the
RIO
C:
IDH
HL:
RIO
vector
found.
vector which indicates drives
This function writes the con-
which are set to read only.
tents of the
FCB
in the main
memory to the directory on the
disk.
30
This function sets the file at-
C:
IEH
A:
Directory code
tributes. The R/Oand system at-
DE:
FCB
address
A:
FFH
(no filel
tributes can
be
set or reset with
17
This function searches for a file.
C:
11H
A: Directory code
this function.
DE: FCB
ad-
OFFH
when the file cannot be
dress
found.
31
This function returns the
BIOS
C:
1FH
HL:
DPB
address
resident disk
parameter
block
18
This function
is
used following
C:
12H
A: Directory code
(DPBl.
function 17 to find the
file
OFFH
when the file cannot
be
whose
name matches
that
found.
specified.
32
This function
sets or gets the
C:
20H
A:
User number
(GET)
user number.
E:
OFFH
for get
E:
User code
19
This
function
deletes
the
C:
13H
A: Directory code
specified file.
DE:
FCB
address
OFFH
when the file cannot be
found.
for
set
33
This function
is
similar to func-
C:
21H A: Return code
tion 20; however, a particular
DE:
FCB
address
OOH
- Normal completion
20 This
function reads
the next
C:
14H
A:
OOH
when the read opera-
record
is
read according to the
Non-zero - Abnormal com ple-
record from the file into memory
DE:
FCB
address
tion
is
completed.
contents
of
positions
RO
tion
at the current DMA address.
Other than
OOH
when the next
through
R2
in the
FCB.
record contains no data.
21
This function writes 128 bytes
C:
15H
A:
OOH
when the write opera-
of data at the current DMA ad-
DE:
FCB
address
tion
is
completed.
dress to a
record
of the file
Other than
OOH
when the disk
34
This function
is
initiated similarly
C:
22H A: Return code
to function 33. However, the
DE:
FCB
address
OOH
- Normal completion
data at the DMA address
is
writ-
Non-zero - Abnormal comple-
ten to the disk.
tion
specified by the
FCB.
is
full.
22
This function generates a new
C:
16H
A: Directory code
file and catalogs it in the direc-
DE:
FCB
address
OFFH
when the
directory
is
tory.
full.
23
This function changes the file
C:
17H
A: Directory code
name.
DE:
FCB
OFFH
when the file cannot be
found
35
This function returns the virtual
C:
23H
file size to the random record
DE:
FCB
address
bytes
(RO
to
R2)
of the
FCB.
36
This function
returns the ran-
C:
24H
dom record position to the ran-
DE:
FCB
address
dom record bytes of the
FCB
after a series of sequential reads
24
This function returns the log-in
C:
18H
HL:
Log-in vector
or writes.
vector which indicates
drives
The least significant bit of L
which are currently on line.
corresponds to drive A and the
most significant
bit.of
H cor-
responds to drive
P.
A
"1"
bi
indicates that the correspon-
ding drive
is
on
line.
A: Contains the same value
as
37
This
function
resets
the
C:
25H
A:
OOH
specified drives according to the
DE:
Drive vector
16-bit
drive vector
indicating
drives
to
be
reset; the least
significant bit of the vector cor-
responds
to drive
A,
and
so
register
L.
forth.
25
This function returns
the cur-
C:
19H
A:
Currently logged-in drive
rently logged-in drive.
01H - Drive A
02H - Drive B
40
This function
is
similar to func-
C:
28H
A:
Return code
tion 34. However, the data writ-
DE:
FCB
address
OOH
- Normal completion
ten
is
all
OOH.
05H - Drive E
06H - Drive F
(Continued)
5-6
5-7
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