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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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