[sebhc] HASL-8 Bug/Corruption?
CarrollWaddell at sc.rr.com
Thu May 13 08:16:08 CDT 2004
When I created the tape images about 15 years ago, I copied the original
Heath tapes, byte for byte, to my PC, and gave them the PID extension.
At that time I was working for IBM and PID was the name given to tapes
sent from the plant containing software updates. This is how I came up
with the PID file extension. If you will look at the H8-5 book, you will
find the format for Heath tapes. There are some SYNC bytes, a byte count
of the number of bytes on the tape, the data, and a CRC check. This is
exactly what the PID file is.
I've also noticed some question about the 040 000 address. When you do a
tape dump to write a tape image, 040 000 and 040 001 contain the
beginning dump address for the tape. In the case of tape programs, if
040 000 - 100
040 001 - 040
That's because all tape programs start at 040 100. (Remember that the
low byte of a word is stored first.)
To dump a tape, 3 things must be set.
1. The 040 000 address must be set with the start dump address.
2. The PC reg must be set to 040 100 (the beginning of the program)
3. The memory address on the front panel LEDS is set to the ending
address of the tape dump.
Hope this helps
Steven Parker wrote:
>> Btw, does anyone have detailed information on the PID format?
> Yea, I posted it last week. Grab the sebhc.0405 file from the
> archives, or get the H8-5 manual. But if you are emulating the serial
> I/O to the tape, the format will probably be transparent anyway since
> PAM takes care of it for you.
>> >Neat, I didn't remember that. I'm guessing that any 11xx1101 would
>> be a
>> >CALL, and any 1100x011 would be a JMP, and 110x1001 would be RET
>> (and of
>> >course, all 00xxx000 are NOP). I suppose for accurate emulation all of
>> >those would have to be handled.
>> Yeah - only problem is I do not know exactly what all the
>> unimplemented opcodes
>> partially decode to ..
> I believe what I listed above is the complete set. If you add all
> those you should have every possible code covered.
>> I loaded hangman and h8demo with the same results - setting PC to
>> 040.000 worked fine, then boom.
> I'm surprised it worked at all. 040.000 is where PAM's ram scratchpad
> is. Tape software starts at 040.100!
> - Steven
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