Reconstruct Comanche 044 from Comanche 051 #1134
Comments
ALARM AND ABORTThe following chunk of three As shown by Norton: This mirrors the addition of the |
PINBALL GAME BUTTONS AND LIGHTSA |
P20-P25The WWPOS and WWVEL limiting in Implementing the above completely resolves bank 40. |
PINBALL NOUN TABLESThree major changes were made to the noun tables between Comanche 44 and 51:
These changes all together resolve bank 42. |
P61-P67
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STAR TABLESThis log section exactly matches Colossus 249. |
PLANETARY INERTIAL ORIENTATION
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STABLE ORBIT - P38-P39The following three words to set NN to 2 were added to P78 between Comanche 44 and 51:
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P34-P35, P74-P75There are a lot of changes in this section relating to using The setting of NN in P34/P74A was added between 44 and 51 and must be removed:
The implementation of S34/35.2 similarly matches Colossus 249. Comanche 51 got some conditional logic here based on the value of NN that must be removed. I believe that Norton shows this here, although he seems to be simplifying what's happening by quite a bit: A bit further down in NOPIE, Comanche 44 references DECTWO instead of NN, again mirroring Colossus 249:
There's one more change in this file that I don't have direct evidence for but believe also happened. If all of the above changes for NN are applied to the Colossus 249 memory layout, bank 35 ends up overflowing. It appears the Colossus team worked around this by moving S34/35.1 into bank 36 via the new tag "S3435LOC". For Colossus 44, we can therefore remove the lines before S34/35.1 and the lines after it. |
TAGS FOR RELATIVE SETLOC AND BLANK BANK CARDSAs mentioned for P34-P35, P74-P75, the tag |
GROUND TRACKING DETERMINATION PROGRAM - P21In to This code doesn't exist in Colossus 249, so there's nothing to compare against directly. Norton shows the change here like this: While that could mean a lot of things, deleting the shift entirely drastically improves bank alignment, so it seems pretty clear this is what happened. |
P30,P37At this point in the reconstruction, it's possible to start using inter-bank references for banks with low differences to try to pinpoint offset errors in other banks. Doing this with the upper banks identifies a possible offset in P30,P37, and a diff between Colossus 249 and Comanche 55 turns up the following INHINT in Colossus has this INHINT, while Comanche 55 does not. While Norton doesn't show this as a change, adding the INHINT back in greatly improves the alignment for a lot of banks. |
RCS-CSM DIGITAL AUTOPILOTThe max rate entries of MANTABLE were changed from 4 deg/s to 2 deg/s between 44 and 51. These need to be taken back to their Colossus 249 values.
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GIMBAL LOCK AVOIDANCEAs above, the final entry of ARATE was changed from 4 deg/s to 2 deg/s. This, too, should match Colossus 249.
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P11Between C45 and C51, the following chunk of code was moved from
Moving it back resolves bank 34. The coding matches Colossus 249. |
P51-P53The following chunk of code was moved from P51A to P51B between revs 44 and 51: The coding in both locations matches Colossus 249. The display logic in R56A changed slightly between 44 and 51, with the addition of the new
Finally, in Comanche 44,
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P40-P47The following chunk of code in Just below that, an asterisk marks where a In |
TVCINITIALIZEHere's where we start to get into the more speculative work. Changes were made to TVCINITIALIZE, and summed up with the unhelpful PCR title "TVC DAP initial errors, CSM alone". Norton shows the changes as follows: At first glance it seems like perhaps this entire chunk might have been added, but deleting it wholesale changes the remaining bugger words after making all of the above changes from this: to this: which makes bank 17 a little bit better, but other things worse. Looking through the lists of changes, this is the only apparent thing left to be fixed in bank 17, so this is likely not the answer. The listing, fortunately, contains some asterisk marks that hold vital clues: This shows everything from Anyways, removing the four marked instructions at the beginning of In other words, not only does it make bank 17 correct, but the resulting alignment change also fixes the remaining errors in all but bank 16. So I think this is most likely to be the correct solution. |
ERASABLE ASSIGNMENTSBefore we move on to fixing the remaining bank 16 errors, erasable definitions need to be cleaned up. Specifically, the definitions of |
P20-P25, revisitedThe only remaining bank with errors is 16, and the only remaining thing Norton has marked in that bank is the small routine This little routine doesn't exist at all in Colossus 249. In Comanche 44, it would have referenced It is, however, the most suspicious section of code remaining, and after systematically ruling out changes throughout the rest of bank 16, I came back to to this: then the bank error goes from 17302 to exactly 0. Admittedly, this is a bit of a stretch, and there's no hard evidence that it was done whatsoever other than the fact that it makes the checksum correct. But the two codings are completely equivalent, so they really wouldn't have had a good reason to change it. My only guesses are that either (a) the person liking the change liked the top formulation better, or (b) these lines had some comments that were made obsolete by the I don't have any other ideas at the moment, though, so until we unearth more documentation (or manage to get a snapshot of LDPLANET in Margaret's Comanche 44 listing) this might be the best we can do. |
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Speaking of which, when I last attempted to nag Margaret about this, about a month ago, my email was returned as undeliverable. Nor has she ever spontaneously contacted me, unprompted by me. I.e., there's no longer any way to reach her, that I know of, and no reason to suspect she'll contact us. |
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@thewonderidiot Would it be worthwhile, do you suppose, to add ##-style comments to the source code at places where the reconstruction differs from Comanche 51? (I admit that I didn't check extensively, but I did look specifically in P20-P25, and didn't see any.) |
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I didn't put any in since there's a lot, but I can go through and do that. I want to get Comanche 45 going first though... that change is stumping me and it's simple enough that I want to try to crowdsource the search for it through the mailing list. |
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It might make sense to crowd-source adding the comments too, since it might prompt more people to look in detail what you've done and how you did it. Otherwise, it's all too easy just to superficially accept it all at face value, as if it just falls from the sky.Sent on my Virgin Mobile Samsung Galaxy S® 5
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I'm going to experiment myself by adding the comments. I will probably poop out before getting very far, but it will be interesting to try. |
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@thewonderidiot Regarding P51-P53, I've found something confusing at the end of routine R56A (just prior to the label R56B). In the Norton doc (p. OPTC-20), this is not marked as a change, and both the Comanche 44 and 55 source code have the identical instruction TCF R56A +2 here. However, the Norton doc describes it as "otherwise, proceed to the 5th line of R56". Which is obviously (I think) not the same thing. To me, this seems like a botched way of saying R56A +5 (i.e., R56A1). Which if true, would be a problem. |
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@thewonderidiot I'm confused about FRAC vs DPFRAC for STAR. How does one know? I want to verify that it's DFRAC in Comanche 44, but I apparently never learned enough about it to know where to look. Also, STAR was 2 words rather than 1 even in Colossus 249, so does that mean it was processed as single precision even though it was allocated as double precision? |
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Norton refers to line numbers within the Programmed Guidance Equations document itself, rather than the listing. The fifth (code) line of Unfortunately, you're not going to find a direct source for FRAC vs. DPFRAC, since all of the lines in the Norton doc that specify scaling also specify the variable (which changed from STAR to STARSAV3, thus masking any other possible changes). The biggest clue that I can find (which is admittedly still kind of a stretch) is that the handling of STAR in Comanche 44 appears to have been the same as STARSAV3 was in Comanche 55. Notably, in while Comanche 44 had So why the change there unless the scaling changed? We can say that that Beyond that, this is simply one of those situations where the bugger words tell the story -- so far as I can tell there's no possible way to make the bank 42 checksum correct if Comanche 44 still has |
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Okay, thanks!Sent on my Virgin Mobile Samsung Galaxy S® 5
…-------- Original message --------
From: Mike Stewart <notifications@github.com>
Date: 12/12/20 11:34 AM (GMT-06:00)
To: virtualagc/virtualagc <virtualagc@noreply.github.com>
Cc: rburkey2005 <rburkey2005@earthlink.net>, Comment <comment@noreply.github.com>
Subject: Re: [virtualagc/virtualagc] Reconstruct Comanche 044 from Comanche
051 (#1134)
Norton refers to line numbers within the Programmed Guidance Equations document itself, rather than the listing. The fifth (code) line of R56 there is indeed R56A, which I believe agrees with the line in the code you're looking at.
Unfortunately, you're not going to find a direct source for FRAC vs. DPFRAC, since all of the lines in the Norton doc that specify scaling also specify the variable (which changed from STAR to STARSAV3, thus masking any other possible changes). The biggest clue that I can find (which is admittedly still kind of a stretch) is that the handling of STAR in Comanche 44 appears to have been the same as STARSAV3 was in Comanche 55. Notably, in PLANET in P51-P53.agc, Colossus 249 has
VLOAD UNIT
STAR
GOTO
CORPLAN
while Comanche 44 had
VLOAD VXSC
STAR
1/SQR3
UNIT GOTO
CORPLAN
So why the change there unless the scaling changed? We can say that that VXSC 1/SQR3 was almost certainly there because 1/SQR3 is not shown as a Comanche 55 addition:
(That change bar is just below, showing the deletion of 1/SQRT3)
Beyond that, this is simply one of those situations where the bugger words tell the story -- so far as I can tell there's no possible way to make the bank 42 checksum correct if Comanche 44 still has FRAC for STAR.
—You are receiving this because you commented.Reply to this email directly, view it on GitHub, or unsubscribe.
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Regarding the "5th line of R56" thing, the explanation about how Norton counts the lines resolves some of the problem, but not all of it. The 5th line of R56 is indeed the program label R56A1. But the TC R56A +2 is still not a jump to R56A1. So there is still a discrepancy between the Norton pseudocode and the Comanche 55 source code there. |
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I'm not following. The 5th line of R56 is |
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Stupid me. The change bar (for R56A1) is immediately following TS=0 rather than at it. I couldn't get that idea out of my head. Thanks. |
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I've finished the first draft of the annotations, though they're only available at the staging site right now rather than the main site: https://virtualagc.github.io/virtualagc/listings/Comanche044/MAIN.agc.html. I'll post them on the main site in a few days if there's not any disqualifying feedback. Every difference between Comanche 44 and 51 is annotated (except for the handful of differences that are comments about changes between 51 and 55). My justifications are usually my own, since I only fell back on issue #1134 when I couldn't figure out a justification for myself. I thought that made a more-useful validation of the process. However, there very seldom seems to be much difference between my explanations and the ones here. Each annotation begins with the word "Reconstruction", so they're relatively easy to find. It's best viewed in Chrome, because (at least for me) Chrome correctly follows all of my links into the exact pages of PDFs that I want to reference. Some other browsers didn't do that for me, and insisted on downloading the entire PDF every time. Certainly they're a lot better viewed in Chrome than in the source-code files. 😄 Anyhow, feedback please! |
ALARM AND ABORTThose are basic instructions, not interpretive. 😉 Generally speaking for all of these, it's more accurate to say that any changes would have been added between 45 and 51. We know the 51-55 changes (gravity model) and 45/2 was a branch (whose difference from 45 is identical to the 51-55 changes). ERASABLE ASSIGNMENTSThe address of FANG changed because GROUND TRACKING DETERMINATION PROGRAM - P21That's not an error. The section in question is: But to show the shift and have a comment for it, he had to break it up into a few lines, using Temporary Storage. Throughout this document Norton is using the bars to show differences from the previous version of this document, not differences in the code from the previous listing. They're largely the same, but there are also some black bars on places where the code didn't change, but Norton decided to add some comments or something. P30,P37Nope, we know the changes between 44 and 45 (COM-4 fix) and between 45 and 45/2 (gravity model). Besides, this INHINT is in bank 35, which is located in a module that wasn't remanufactured between 44 and 45/2. (Plus, 45/2 was a branch and nothing that went into it impacted any later versions). This change was also made between 45 and 51. P34-P35, P74-P75The difference between the two is that P40-P47The Nope, those three lines related to this one in Norton: This change is unrelated to the PINBALL NOUN TABLESThat's ancillary evidence, but really the conclusion was drawn from the line below, which encodes three instances of DPFRAC in octal. Colossus 249 has And that word needs to be 32655 for the checksum to be correct. TVCINITIALIZEActually, that PCR is the single biggest argument against the changes I made, and gave Niklas and I quite a bit of trouble while working on this. We figured from that title that the entire |
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@thewonderidiot Regarding the DELVSAB=|DELVSIN| change in P40-P47. Obviously I was very careless with that annotation, since it's pretty obvious the pseudocode doesn't match the code. But it it makes the justification much trickier. Should my justification be something like the following? The addresses are off by a few after a certain point in this file. Diff'ing with Colossus 249 you find a stray set of instructions. Comparing to the pseudocode you find that they match DELVSAB=|...|. Noting that the Norton page is rev 2 and that there's no change bar, you conclude that the change occurred prior to rev 45/2. Later ... in thinking about it, I've gone ahead and written it up pretty much like that. |
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I've now modified the annotations per the feedback given above. I don't know if there's the patience to wade through them again for yet another check. If so, only the specific annotations referenced above have been changed, and that makes it go a lot quicker. (Two or three new annotations have been added via hyperlinks, at points where there was no actual change, to provide some supporting data.) I did not try to generically change every place where I had said there was a change from Comanche 55 to saying instead that it was a change from Comanche 51. That's partly because I generally only referenced 55 when I thought I had a specific reason to do so; but also because it's a big hassle. Perhaps I'll revisit that later. Again, I'll keep the changed pages in staging-area website for a few days, and only migrate them to the main website later. |
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I think the justification for |
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@thewonderidiot Done! The succeeding annotation (COM 10) was also tweaked, because I had mistakenly said it related to a problem fixed in Comanche 49, whereas it was actually reported in Comanche 49. |
Branch
comanche044
Changed Bugger Words from Closest Program (Comanche 051)
Known Differences
Resources
Notes
There's very, very few asterisks in the Comanche 55 listing. I think at least one of the subroutine differences may have been deletions, rather than changes/additions. Some of the changes between 44 and 51 are masked by the changes made from 51 to 55 (addition of the R-2 lunar potential model), and others are masked by changes in close proximity in the revisions between 44 and 51.
There is a very large number of banks that changed (30!), but I think this number is misleading. Most of the banks only have very small differences in the bugger words, which suggests that the code in those banks didn't change, but rather offsets in a bank they reference changed.
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