Basic Disk Operating System (BDOS) Functions
4-10
GET
CONSOLE
STATUS
ENTRY
RETURN
CL:
OBH
FUNCTION
11
AL: Console Status
GET
CONSOLE
STATUS
The
Get
Console Status function checks
to
see
if
a character has been typed
at
the
logical console device
(CONSOLE).
If
a character
is
ready, the value 01H
is
returned in register AL. Otherwise the value
OOH
is
returned.
RETURN
VERSION NUMBER
ENTRY
RETURN
CL: OCH
FUNCTION
12
BX:
Version Number
RETURN
VERSION
NUMBER
The
Return
Version
Number
function provides information which allows version-
independent programming. A two-byte value
is
returned
designating the
CP/M
version number, as follows.
BDOS
File Operations
BH
00
00
00
00
01
BL
00
20
2l-2F
22
Version
CP/M
< 2.0
CP/M
2.0
CP/M>
2.0
CP/M-86
MP/M
Functions
13
through
52 are related
to
disk file operations
under
CP/M-86.
In
many
of
these operations,
DX
provides the DS-relative offset
to
a File
Control
Block (FCB).
The
FCB
data
area
consists
of
a sequence
of
33
bytes for sequential
access,
or
36 bytes for
random
access. The default
FCB
normally located
at
offset
005CH from register
DS
can be used for
random
access files, since bytes 007DH,
007EH,
and
007FH are available for this purpose.
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