[Coco] Re: optimizing

[Gene Heskett]

On Saturday 13 December 2003 00:07, KnudsenMJ at aol.com wrote:
>In a message dated 12/10/03 2:32:41 PM Eastern Standard Time,
>
>gene.heskett at verizon.net writes:
>> You've not heard of that?  Amazing.  You build it into your
>> os9boot file, usually right after os9p3, which is right after
>> os9p2, and then use it as a subroutine in your program.
>
>OK, no, I don't recall it.  Not sure that I even have an os9p3 in my
> boot -- ISTR that was for putting in some odd leftover
> initialization parameters, not debugging.
>
>By then I was doing most of my work in C, and debugging was with the
> "pile of printfs" method.
>
>FWIW, I've never had Shell+ either, though that was for technical
> reasons.  I suspect almost all OS-9 users run it today.
>
>>  os9p3 is an error interceptor, taking any error return and
>> reading its description from defs/error.h or some such, thereby
>> relieving you from wearing out the manuals looking up the error
>> codes.  It makes the manuals last a lot longer :-)
>
>OS-9 had an "Error" command that you executed just once, and after
> that for the duration of the session (boot), you'd get English
> error messages instead of the numbers.  But I think that was Level
> 1 only, and went away in L2.  Sounds like os9P3 was a replacement
> for that.
>
>>  os9p4 is a register dumper, adding the call f$regdmp to the os. 
>> Save the CC on the stack, call it from anyplace in your program
>> and the registers will be dumped to stdout.
>
>OK, much like the firmware monitor in the KIM-1.  I did build that
> capability into a custom computer I built at Bell Labs as part of a
> big signal processing network, so I do like the concept.  Trouble
> is, you often need contents of memory, not just registers, to
> figure out why your program went into the weeds.
>
>>  When it returns, pop the CC off the stack and continue on your
>> merry way with nothing changed.  Its CC output is correct as
>> printed to std out, but will not be correct by the time it
>> returns, hence the pushs, pulls to save it for your program.  Its
>> a great troubleshooter.
>
>And could you hack, er, modify the register contents before you
> resumed?

No, not normally.  The program simple resumed operation as if the 
regdumper wasn't there, all conditions restored including cc if you 
did it right.  In other words, no "breakpoint", just a trace of the 
state of the cpu as it fly's by.  Thats enough IMO.

>I remember that's how interactive user input worked onthe KIM-1 --
> when you wanted to prompt for an input, put a breakpoint.  User
> keys the desired value into a register and resumes.  --Mike K.

-- 
Cheers, Gene
AMD K6-III at 500mhz 320M
Athlon1600XP at 1400mhz  512M
99.22% setiathome rank, not too shabby for a WV hillbilly
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by Gene Heskett are:
Copyright 2003 by Maurice Eugene Heskett, all rights reserved.