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CPIM-86 Bootstrap and Adaptation Procedures
(0040:0) CS DS ES SS OOOOH:
(0040:) 2500H:
(0040:) 2AOOH:
Figure 8-2 CPM.SYS File Organization
G D# 1\ 0
V
I I I I I I I I I I I I
(CCP and BDOS)
JMP INIT
JMP SETIOB
(BIOS)
INIT: .. JMP OOOOH
GD#1 is the Group Descriptor containing the A-Base value followed by a "0"
terminator. The BIOS contains an "INCLUDE" statement that reads the appropri-
ate file containing the disk definition tables.
The CPM.SYS file is read by the LOADER program beginning at the address given
by A-Base (byte address 0400H), and control is passed to the INIT entry point at
offset address 2500H. Any additional initialization, n,ot performed by LOADER,
takes place in the INIT subroutine. On completion, INIT executes a JMP OOOOH to
begin execution of the CCP. The actual load address of CPM.SYS is determined
entirely by the address given in the A-Base field which can be changed if you wish to
execute
CP/M-86
in another region of memory. Note that the region occupied by
the operating system must be excluded from the BIOS memory region table.
8-5
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