Chapter 6
Advanced
BIOS
Functions
The
CP/M-86
operating system distributed with the
APC
contains a customized
BIOS, called the CBIOS, with features specific
to
the APC.
CRT
control codes,
or
escape sequence functions, reside in the BIOS
and
are called by BDOS functions.
Extended functions also reside in the
BIOS
and
are called directly by application
programs using
program
interrupt #220.
The
relationship among applicant
pro-
grams, the BDOS,
and
CBIOS
is
shown in Figure 5-1.
CRT
ESCAPE
SEQUENCE
FUNCTIONS
The
CONOUT
(Write Console Character Out) routine in the BIOS recognizes
CRT
escape code sequences
and
performs the
appropriate
action in response
to
the codes
received. Any
of
the following
standard
functions
can
be used
to
effect the
APC
console escape sequences.
• BDOS function 2 (Console Output)
• BDOS
function 6 (Direct Console
I/O)
• BDOS function
50
(Direct BIOS call)
Format and Definitions
Escape sequences consist
of
three kinds
of
fields: a sequence
introducer
that
identifies the instruction as
an
escape sequence, one
or
more parameters,
and
a final
character.
For
example, the following escape sequence moves the cursor
up
two
lines.
ESC[2A
The general
format for the above escape sequence
ESC[PnA
presents the basic elements
of
all
APC
escape sequences.
6-1
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