[sebhc] H17 ROM ?
Dwight K. Elvey
dwight.elvey at amd.com
Fri May 21 16:01:08 CDT 2004
Hi
The other file he should look at, if he is going to trap
I/O is H17def.acm. Also, one of the two, u8250.acm or u8251.acm.
I forget which was on the H17 card. I think it was the 8251.
There was one thing that I recall. There was a timing error
in the original H17 ROM. It had something to do with action
when writing the last sector of a track. I think it was
a head load timing issue. The normal driver on the HDOS
disk patched this but for someone doing direct calls to
the ROM, one should be aware of this.
Dwight
>From: "Steven Parker" <sp11 at hotmail.com>
>
>Dave says:
>>I've been disassembling the H17 ROM (found it in the archive),
>>As far as I can tell, it has very little to do with the disk
>>hardware - it appears to be chock full of various utility
>>subroutines (like divides etc.) but almost no disk functions.
>>Just a little boot stub at the end.
>
>Are you looking at your disassembly, or just that partial listing in the
>archives? (That listing only shows the very beginning of the ROM).
>Disk-related entry points in the H17 ROM include:
>
>R.SYDD EQU 033316A ROM device driver
>R.MOUNT EQU 033345A Mount new device
>R.ABORT EQU 033366A Abort any active I/O
>R.XOK EQU 033374A Exit with OK status
>R.XIT EQU 033375A Exit
>R.READ EQU 034077A Read from disk
>R.READR EQU 034321A Read regardless of protection
>R.WRITE EQU 034336A Process disk write
>R.CDE EQU 035136A Count disk errors
>R.DTS EQU 035172A Decode track and sector
>R.SDT EQU 035225A Seek desired track
>R.MAI EQU 035251A Move arm in
>R.MAO EQU 035254A Move arm out
>R.DLY EQU 035303A Delay by clock
>R.LPS EQU 035321A Locate proper sector
>R.RDB EQU 036044A Read disk byte
>R.SDP EQU 036062A Set device parameters
>R.STS EQU 036165A Skip this sector
>R.WHD EQU 036235A Wait for hole detect
>R.STZ EQU 036254A Seek track zero
>R.WNH EQU 036271A Wait for no hole
>R.UDLY EQU 036302A Microsecond delay loop
>R.WSC EQU 036307A Wait for sync character
>R.WSP EQU 036343A Write sync pattern
>R.WNB EQU 036373A Write next byte
>
>BOOT EQU 037014A Boot disk system
>DDIAG EQU 037262A Disk diagnostic
>
>As you see, the ROM has an entire device driver - but it may be easier to
>look over the source for the HDOS driver (sydvd.asm) that I mentioned in my
>last message.
>
>>I had been assuming that the ROM would contain all the disk
>>functions, so that the operating system could access the disk
>>no matter which controller/drive you had installed
>
>Different controllers had different ROMs. The H17 ROM only addresses its
>own controller.
>
>Ron said:
>>Look in the PAM-37 Panel Monitor Operation/service Manual. That book
>>contains a listing with routines for and references to all the disk types.
>
>I don't think the PAM-37 listing has made it into the archives - I've been
>looking for it myself. Ironically, even though I am the author of PAM-37, I
>don't have a copy of the listing!
>
>But yes, PAM-37 was the only monitor ROM able to boot from all the disk
>flavors, and that was a major objective of the development project.
>However, as I recall, it still relied on the code in the controller ROMs.
>
>Cheers,
>
>- Steven
>
>_________________________________________________________________
>FREE pop-up blocking with the new MSN Toolbar get it now!
>http://toolbar.msn.click-url.com/go/onm00200415ave/direct/01/
>
>--
>Delivered by the SEBHC Mailing List
>
--
Delivered by the SEBHC Mailing List
More information about the Sebhc
mailing list