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Re: Apollo 11 source code released

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Jeff Findley formulated the question :
> In article <duhkokFondfU1@mid.individual.net>, 
> niklas.holsti@tidorum.invalid says...
>> 
>> On 16-07-11 13:44 , Jeff Findley wrote:
>>> In article <p2j6obt05vvmbg0i08afngatpmurap66e6@4ax.com>,
>>> fjmccall@gmail.com says...
>>>> 
>>>> JF Mezei <jfmezei.spamnot@vaxination.ca> wrote:
>>>> 
>>>>> On 2016-07-10 13:33, Niklas Holsti wrote:
>>>>> 
>>>>>> A custom-made computer:
>>>>>> 
>>>>>> https://en.wikipedia.org/wiki/Apollo_Guidance_Computer
>>>>> 
>>>>> 
>>>>> Very interesting read. Thanks.  It mentions it was the first computer
>>>>> made of integrated circuits. Looks like it was all fixed decimal
>>>>> notation as opposed to floating point. That would have a big impact on
>>>>> the heavy math done for guidance and navigation (lots of angles/trig 
>>>>> etc).
>>>>> 
>>>>> Was all the code written in assembler or were portions done in higher
>>>>> level languages ?
>>>>> 
>>>> 
>>>> No HOL.  Have you looked at the specifications for these things?
>>> 
>>> The Wikipedia entry clearly says this, "AGC software was written in AGC
>>> assembly language and stored on rope memory."
>> 
>> But the Wikipedia entry also says this:
>> 
>> "The AGC also had a sophisticated software interpreter, developed by the 
>> MIT Instrumentation Laboratory, that implemented a virtual machine with 
>> more complex and capable pseudo-instructions than the native AGC. These 
>> instructions simplified the navigational programs. Interpreted code, 
>> which featured double precision trigonometric, scalar and vector 
>> arithmetic (16 and 24-bit), even an MXV (matrix × vector) instruction, 
>> could be mixed with native AGC code. While the execution time of the 
>> pseudo-instructions was increased (due to the need to interpret these 
>> instructions at runtime) the interpreter provided many more instructions 
>> than AGC natively supported and the memory requirements were much lower 
>> than in the case of adding these instructions to the AGC native language 
>> which would require additional memory built into the computer (at that 
>> time the memory capacity was very expensive). The average 
>> pseudo-instruction required about 24 ms to execute. The assembler and 
>> version control system, named YUL for an early prototype Christmas 
>> Computer,[8] enforced proper transitions between native and interpreted 
>> code."
>> 
>> Reminds me of the SWEET16 VM in the Apple II, 
>> https://en.wikipedia.org/wiki/SWEET16.
>
> The examples given for functionality of the interpreted code bits sound 
> an awful lot like subroutines.  

The description as quoted is insufficient to distinguish between a 
"subroutine-ish" stored program and a microcode implementation, but the 
former is more likely.  Note that C64 and Apple II did their BASIC 
implementations this way (ROM subroutines), and Forth and Pascal were 
available as add-in boards.  You could also think of the IBM-PC BIOS in 
this way, too.

I understand the IBM 360 was an example of a computer using microcode 
where the microcode could be changed in the field.  Microcode 
essentially provides a virtual machine written on top of a very dumb 
and very fast "inner processor".  This is still used in x86 
architectures, as well as having been part of PDP-11 and VAX building.  
The PDP-11 is rumored to have used the PDP-8  cpu/alu design to 
implement the "inner processor".

(comment for the other branch of this thread:  compiler designers did a 
lot of learning about optimization in the 1980s and 1990s)

/dps


-- 
There's nothing inherently wrong with Big Data. What matters, as it 
does for Arnold Lund in California or Richard Rothman in Baltimore, are 
the questions -- old and new, good and bad -- this newest tool lets us 
ask.  (R. Lerhman, CSMonitor.com)

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Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-10 12:43 -0400
  Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-10 20:33 +0300
    Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-10 18:28 -0400
      Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-10 21:27 -0400
      Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-11 00:36 -0700
        Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-11 06:44 -0400
          Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-11 16:20 +0300
            Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-11 20:53 -0400
              Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-12 14:36 -0400
                Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-12 18:11 -0700
              Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-12 23:37 +0300
                Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-12 18:14 -0700
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-13 21:01 +0300
                Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-13 20:06 -0700
                Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-14 06:44 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-15 23:54 +0300
                Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-17 11:49 -0400
                Re: Apollo 11 source code released William Mook <mokmedical@gmail.com> - 2016-07-17 18:41 -0700
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-18 09:20 +0300
                Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-14 11:38 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-16 00:10 +0300
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-15 22:26 +0300
                Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-20 10:49 -0700
              Re: Apollo 11 source code released Snidely <snidely.too@gmail.com> - 2016-07-14 09:12 -0700
          Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-11 11:51 -0400
            Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-12 02:19 +0300
              Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-11 20:58 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-12 09:24 +0300
                Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-12 10:10 -0700
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-13 21:07 +0300
                Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-13 20:08 -0700
                Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-14 11:25 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-15 22:39 +0300
                Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-20 10:40 -0700
                Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-12 14:41 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-12 23:26 +0300
                Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-12 21:41 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-13 08:54 +0300
                Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-13 06:43 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-13 21:08 +0300
                Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-14 11:34 -0400
                Re: Apollo 11 source code released Niklas Holsti <niklas.holsti@tidorum.invalid> - 2016-07-15 23:06 +0300
                Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-15 19:48 -0400
                Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-15 19:59 -0400
                Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-17 12:00 -0400
                Re: Apollo 11 source code released Jeff Findley <jfindley@cinci.nospam.rr.com> - 2016-07-17 12:14 -0400
                Re: Apollo 11 source code released JF Mezei <jfmezei.spamnot@vaxination.ca> - 2016-07-17 12:56 -0400
              Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-12 10:04 -0700
            Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-12 09:43 -0700
          Re: Apollo 11 source code released Alain Fournier <alain245@videotron.ca> - 2016-07-11 19:43 -0400
  Re: Apollo 11 source code released Fred J. McCall <fjmccall@gmail.com> - 2016-07-10 11:39 -0700
  Re: Apollo 11 source code released William Mook <mokmedical@gmail.com> - 2016-07-11 18:28 -0700

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