Command (CMD) File Generation
Table 3-2 Group Descriptors
G-TYPE
GROUP-TYPE
1
Code
Group
2
Data
Group
3
Extra
Group
4
Stack
Group
5
Auxiliary
Group
# 1
6
Auxiliary
Group
#2
7
Auxiliary
Group
#3
8
Auxiliary
Group
#4
9
Shared Code
Group
10
-
14
Unused,
but
Reserved
15
Escape Code for Additional Types
All remaining values in the
Group
Descriptor
are given in increments
of
16-byte
paragraph
units with
an
assumed low-order 0 nibble
to
complete the 20-bit address.
G-Length
gives the
number
of
paragraphs
in the group. Given a G-Iength
of0080H,
for
example,
the
size
of
the
group
is 00800H
(or
2048D) bytes. A-Base defines the
minimum
and
maximum
size
of
the
memory
area
to
allocate
to
the group.
G-
Type 9
marks
a "pure" code
group
for
use
under
future versions
of
CP/M-86.
Presently a
Shared
Code
Group
is
treated
as a
non-shared
Program
Code
Group
under
CP/M-86.
The
memory
model described by a
header
record
is
implicitly determined
by
the
group
descriptors.
The
8080
Memory
Model
is
assumed when only a code
group
is
present, since
no
independent
data
group
is
named.
The
Small
Memory
Model is
implied when
both
a code
and
data
group
are present,
but
no
additional
group
descriptors occur. Otherwise, the
Compact
Memory
Model
is
assumed when the
CMD
file
is
loaded.
3-7
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