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RELHOW.DOC
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1984-04-29
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3KB
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66 lines
RELOC.ASM IS A REGENERATED SOURCE FILE FOR THE PROGRAM PORTION OF RELOC.COM (CPM.COM).
THE COM FILE CONTAINS, IN ADDITION TO THIS PROGRAM PORTION, A COPY OF CP/M
ORG'ED AT 0, AND A RELOCATION TABLE WHICH MARKS ADDRESSES TO BE MODIFIED IN
RELOCATING THE SYSTEM. THE RELOCATION IS NOT COMPLETELY GENERAL, AS ONLY THE
HIGH BYTE OF EACH ADDRESS IS MODIFIED.
REL1.ASM IS A MODIFIED VERSION OF RELOC.ASM, WITH THE SERIAL-NUMBER CHECKING ROUTINES
REMOVED. IT CAN BE RUN UNDER DDT, AND GENERATES A NEW SYSTEM WITH THE SAME
SERIAL NUMBER AS THE SYSTEM CURRENTLY RUNNING.
REL1.COM IS THE OBJECT CODE OF REL1.ASM, COMBINED WITH THE SYSTEM AND RELOCATION TABLE
OF RELOC.COM. IT IS GENERATED BY LOADING RELOC.COM UNDER DDT AND THEN GIVING
THE COMMANDS "IREL1.HEX" AND "R" TO REPLACE THE PROGRAM PORTION. ONE THEN
EXITS FROM DDT AND CREATES THE FILE WITH "SAVE 35 REL1.COM".
REL1.COM IS USED JUST LIKE RELOC.COM.
REL256.COM IS A VERSION OF REL1.COM WITH THE SYSTEM RELOCATED TO BEGIN 256 BYTES LOWER
IN MEMORY THAN USUAL. THUS, IN A 16K SYSTEM, THE BIOS BEGINS AT 3D00 INSTEAD
OF 3E00, THE CCP BEGINS AT 2800 (HEX) INSTEAD OF 2900, AND SO FORTH. THE POINT
OF THIS IS TO LEAVE AN EXTRA 256 BYTES IN THE BIOS FOR ADDITIONAL I/O DRIVERS.
REL256 IS OPERATED JUST LIKE RELOC, BUT SOME OF THE AUXILIARY PROCEDURES ARE
DIFFERENT:
1. YOUR BOOT MUST BE REASSEMBLED TO LOAD THE SYSTEM BEGINNING ONE PAGE
LOWER IN MEMORY, AND TO LOAD 2 EXTRA SECTORS.
2. YOUR BIOS MUST BE REASSEMBLED TO BEGIN ONE PAGE LOWER THAN USUAL.
3. WHILE THE BIAS TO BE USED IN PATCHING-IN THE BOOT REMAINS AT 900H,
THE NEGATIVE BIAS FOR BIOS MUST BE CHANGED BY ADDING 100 HEX TO IT.
FOR EXAMPLE, IN A 32K SYSTEM, THE BIAS IS CHANGED FROM A080 TO A180.
REL512.COM IS JUST LIKE REL256.COM EXCEPT THAT THE SYSTEM BEGINS TWO PAGES (512 BYTES)
LOWER THAN USUAL. BOOT AND BIOS MUST BE CHANGED ACCORDINGLY: LOAD SYSTEM
TWO PAGES LOWER, LOAD FOUR EXTRA SECTORS, ORG BIOS 200H LOWER THAN USUAL,
AND ADD 200H TO THE LOAD BIAS
REL768.COM IS JUST LIKE REL256.COM EXCEPT THAT THE SYSTEM BEGINS 3 PAGES LOWER THAN
USUAL (768 BYTES). THUS THE CHANGES IN PROCEDURE INVOLVE LOADING 3 PAGES
LOWER (300H), LOADING 6 EXTRA SECTORS, AND ADDING 300H TO THE LOAD BIAS.
REL768 CANNOT BE FULLY UTILIZED, SINCE THERE ARE ONLY 5 EXTRA SECTORS
AVAILABLE ON TRACK 1 (SECTORS 22 THROUGH 26).
BOOT256 IS DIGITAL SYSTEMS' BOOTSTRAP MODIFIED FOR A 32K SYSTEM CREATED WITH
REL256. THE PARAMETERS THAT HAVE BEEN CHANGED ARE MARKED BY "*****".
CBIO256 IS DIGITAL SYSTEMS' CBIOS WITH DRIVERS ADDED FOR AN IMSAI SI0-2 BOARD (CONSOLE
ON PORTS 2 AND 3), MODIFIED FOR 32K SYSTEM CREATED WITH REL256 (IE. 256 EXTRA
BYTES IN THE BIOS). CHANGED PARAMETERS ARE MARKED AS IN BOOT. THE SIO
BOARD IS INITIALIZED WHEN THE SYSTEM IS BOOTED.