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mankeli
Registered: Oct 2010
Posts: 146 |
Spindle and Sparkle demos not launching
Can someone explain why demos using Sparkle or Spindle loaders can't be run from 1541U by selecting the launch file and using "mount & run"?
You got to use "Run Disk" for the whole image. 99.9999% of the C64 demos can be launched with mount & run, and somehow this only seems affect those aforementioned loaders. |
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tlr
Registered: Sep 2003
Posts: 1791 |
Quote: But we were talking about "I" command, no? When there is no error, its all fine? :)
it is, but a subsequent custom track seek needs to consider that the stepper bits can be incorrect and do "the dance" it self. |
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chatGPZ
Registered: Dec 2001
Posts: 11390 |
But how would they be, after succesfull "I"? Wouldn't the DOS set them at least once? |
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tlr
Registered: Sep 2003
Posts: 1791 |
Not sure if the are touched at all if not trying to move the head. A seek to track 18 if you are already there probably won't move anything. |
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Sparta
Registered: Feb 2017
Posts: 49 |
Please correct me if I’m mistaken but it seems to me that this is only a problem if you don’t know which track you are on before the first 0.5 track step is taken by the loader. |
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Krill
Registered: Apr 2002
Posts: 2981 |
Quoting SpartaPlease correct me if I’m mistaken but it seems to me that this is only a problem if you don’t know which track you are on before the first 0.5 track step is taken by the loader. Well seems to me that generally you don't know which track you're on right after a reset/powercycle. =) |
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Martin Piper
Registered: Nov 2007
Posts: 726 |
Quote: Quoting SpartaPlease correct me if I’m mistaken but it seems to me that this is only a problem if you don’t know which track you are on before the first 0.5 track step is taken by the loader. Well seems to me that generally you don't know which track you're on right after a reset/powercycle. =)
And until the disk spins, a GCR sync mark is found, the GCR header is read, decoded, and the track and sector bytes are discovered. :) |
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Sparta
Registered: Feb 2017
Posts: 49 |
Quoting KrillWell seems to me that generally you don't know which track you're on right after a reset/powercycle. =)
Can’t be too far from the one we were on before power cycling. ;p
Anyway, what I mean is that in the case of Sparkle (and Spindle too), the installer loads from track 18. Once the BAM is read after drive reset (via the above mentioned JSR $d00e in the M-E bootstrap code), I know I am still/back on track 18 and I can set the stepper bits accordingly. |
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chatGPZ
Registered: Dec 2001
Posts: 11390 |
Except when some kind of DMA loading for the first file was involved (Like 1541U or TC64 does) - which is what this thread is all about :) |
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Sparta
Registered: Feb 2017
Posts: 49 |
That’s what the read BAM call will remedy:
1. By some means (LOAD, DMA), Sparkle’s installer gets loaded to the c64
2. Drive reset (in case of real HW)
3. RUN
4. M-E bootstrap code gets uploaded and executed in drive’s buffer
5. Bootstrap reads BAM
6. I am on track 18 |
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Sparta
Registered: Feb 2017
Posts: 49 |
Tested so far on U, U2, and U2+, 1541-II, and Oceanic. |
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