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Forums > C64 Coding > Nucrunch 0.1
2016-02-04 10:02
ChristopherJam

Registered: Aug 2004
Posts: 1378
Nucrunch 0.1

Continuing from the benchmarks WVL posted in Doynamite 1.x:

I dusted off my unfinished nucrunch in December to pack just enough of the second page of Reutastic to give me some workspace for some precalculations. Pity I didn't schedule enough time to pack the entire demo, else it would have been ~90 blocks instead of 190, but I digress. I've spent bits of the past month cleaning up the code, optimizing the packer (mostly by porting it from python to rust :P), and adding reverse direction support.

It's still no more than a component, with an commandline packer and asm decrunch subroutine, but no tools yet for generating an executable from a single commandline. It does at least now support multiple input segments that are unpacked to their destination addresses, and it's also now useable enough to for me to do some benchmarking.

In short, doynamite's ratio looks pretty unbeatable for anything lz based; my ratio's almost identical despite a somewhat different encoding.

Where I can win though is speed at that ratio; nucrunch is usually ten to twenty percent faster. The one exception in the test corpus is 6.bin, where it's 20% slower; not sure why yet.

I've added the times for pucrunch -ffast below for to complete the comparison. Last two columns are nucrunch, and nucrunch -r (the latter decodes in reverse; should be a more useful component for single filers)

If anyone wants to have a play at this stage, poke me and I'll upload some source. Failing that I'll hold off until I at least have something that can make onefilers without any faffing about with relocating the last couple of pages by hand.

filesizes
#   bin   rle wvl-f wvl-s    tc    bb  pu-f doyna nucru rnucr
- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
1 11008  8020  4529  4151  4329  3383  3711  3265  3225  3230
2  4973  4314  3532  3309  3423  2648  3005  2512  2498  2490
3  3949  3498  2991  2617  2972  2187  2530  2108  2091  2093
4  7016  6456  4242  4085  4225  3681  3924  3617  3622  3614
5 34760 27647 25781 24895 25210 21306 21182 20405 20447 20516
6 31605 12511 11283 10923 11614  9194  9203  8904  8915  8894
7 20392 17295 12108 11285 11445  9627  9789  9289  9140  9144
8  5713  5407  4179  3916  3936  3251  3656  3132  3165  3187
9  8960  7986  6914  6896  6572  5586  6000  5430  5502  5486

filesize in %
#   bin   rle wvl-f wvl-s    tc    bb  pu-f doyna nucru rnucr
- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
1   100  72.9  41.1  37.7  39.3  30.7  33.7  29.7  29.3  29.3
2   100  86.7  71.0  66.5  68.8  53.2  60.4  50.5  50.2  50.1
3   100  88.6  75.7  66.3  75.3  55.4  64.1  53.4  53.0  53.0
4   100  92.0  60.5  58.2  60.2  52.5  55.9  51.6  51.6  51.5
5   100  79.5  74.2  71.6  72.5  61.3  60.9  58.7  58.8  59.0
6   100  39.6  35.7  34.6  36.7  29.1  29.1  28.2  28.2  28.1
7   100  84.8  59.4  55.3  56.1  47.2  48.0  45.6  44.8  44.8
8   100  94.6  73.1  68.5  68.9  56.9  64.0  54.8  55.4  55.8
9   100  89.1  77.2  77.0  73.3  62.3  67.0  60.6  61.4  61.2

number of frames to depack
#   bin   rle wvl-f wvl-s    tc    bb  pu-f doyna nucru rnucr
- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
1     0    11    13    14    15    58    54    27    22    22
2     0     5     7     7     9    38    39    17    14    14
3     0     4     6     6     7    28    31    12    10    10
4     0     8     9     9    10    43    51    20    17    18
5     0    36    39    42    59   300   298   119   104   107
6     0    20    25    25    37   126   152    49    59    59
7     0    22    25    26    32   138   139    60    51    52
8     0     6     8     8    10    43    47    18    16    17
9     0     9    12    12    16    73    81    32    28    29

kilobytes output per second
#   bin   rle wvl-f wvl-s    tc    bb  pu-f doyna nucru rnucr
- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
1        49.0  41.4  38.5  35.9   9.3  10.0  20.0  24.5  24.5
2        48.7  34.8  34.8  27.0   6.4   6.2  14.3  17.4  17.4
3        48.3  32.2  32.2  27.6   6.9   6.2  16.1  19.3  19.3
4        42.9  38.2  38.2  34.3   8.0   6.7  17.2  20.2  19.1
5        47.3  43.6  40.5  28.8   5.7   5.7  14.3  16.4  15.9
6        77.4  61.9  61.9  41.8  12.3  10.2  31.6  26.2  26.2
7        45.4  39.9  38.4  31.2   7.2   7.2  16.6  19.6  19.2
8        46.6  35.0  35.0  28.0   6.5   6.0  15.5  17.5  16.5
9        48.7  36.5  36.5  27.4   6.0   5.4  13.7  15.7  15.1

cycles per byte consumed
#   bin   rle wvl-f wvl-s    tc    bb  pu-f doyna nucru rnucr
- ----- ----- ----- ----- ----- ----- ----- ----- ----- -----
1     0    27    56    66    68   337   286   163   134   134
2     0    23    39    42    52   282   255   133   110   111
3     0    22    39    45    46   252   241   112    94    94
4     0    24    42    43    47   230   255   109    92    98
5     0    26    30    33    46   277   277   115   100   103
6     0    31    44    45    63   269   325   108   130   130
7     0    25    41    45    55   282   279   127   110   112
8     0    22    38    40    50   260   253   113    99   105
9     0    22    34    34    48   257   265   116   100   104

decrunch time for nucrunch/rnucrunch relative to doynamite
1:  81.5% (-18.5%)  81.5% (-18.5%)
2:  82.4% (-17.6%)  82.4% (-17.6%)
3:  83.3% (-16.7%)  83.3% (-16.7%)
4:  85.0% (-15.0%)  90.0% (-10.0%)
5:  87.4% (-12.6%)  89.9% (-10.1%)
6: 120.4% ( 20.4%) 120.4% ( 20.4%)
7:  85.0% (-15.0%)  86.7% (-13.3%)
8:  88.9% (-11.1%)  94.4% ( -5.6%)
9:  87.5% (-12.5%)  90.6% ( -9.4%)
 
... 92 posts hidden. Click here to view all posts....
 
2016-02-14 18:13
ChristopherJam

Registered: Aug 2004
Posts: 1378
Size is definitely pertinent. nucrunch is hardly small at the moment.
nucrunch   342
rnucrunch  394
tinycrunch 151
2016-02-14 19:52
HCL

Registered: Feb 2003
Posts: 716
Comparing B2 and Bitfire.. The encoders are generating the same format, however not compatible. It has been the same since the first release of ByteBoozer1.0. ByteBoozer2.0 and Bitfire (and probably most others today) are searching through *all* possible ways to win bits, where as Bb1.0 has a faster gready algorithm. Remember it was running on the c64 also(!), but that's why B2 compresses better. B2 and Bitfire encoders do have rather different ways of achieving their goals, which explains the small differences we see in compression rate.

B2 and Bitfire decrunchers are more identical than the encoders. I was working like hell to find another code design than Bitbreaker's that still wasn't slower, but i guess he already examined all those possibilities before me :). So i guess we sort of agree on this rather optimal way of decrunching lz-code.. Now i'm very qurious on what new tricks Nucrunch is bringing up to the surface :).
2016-02-14 22:25
MagerValp

Registered: Dec 2001
Posts: 1055
LZMV4k decruncher is 137 bytes, LZMV256 is 89 bytes.
2016-02-14 23:43
Martin Piper

Registered: Nov 2007
Posts: 634
Depends if you're including all the post BASIC setup and memory moving code.
2016-02-14 23:48
ChristopherJam

Registered: Aug 2004
Posts: 1378
Quoting Martin Piper
Depends if you're including all the post BASIC setup and memory moving code.


Just the decrunch engine; assume something else has loaded the data/set $01/cleared interrupts etc and the source and destination areas placed so as to not need special handling.
2016-02-15 05:51
lft

Registered: Jul 2007
Posts: 369
Quoting MagerValp
The trick is to ensure that the compressed stream ends with a match. If it ends with a literal, include the literal data without any control bytes at the correct location.


That is absolutely brilliant!
2016-02-15 07:37
ChristopherJam

Registered: Aug 2004
Posts: 1378
Quoting lft
Quoting MagerValp
The trick is to ensure that the compressed stream ends with a match. If it ends with a literal, include the literal data without any control bytes at the correct location.


That is absolutely brilliant!


It is, rather. MagerValp, how were you planning to terminate the stream?

My EOF's over a byte long, and checking end address seems slow if it's not necessarily on a page boundary.
2016-02-15 07:43
ChristopherJam

Registered: Aug 2004
Posts: 1378
Quoting HCL
Comparing B2 and Bitfire.. The encoders are generating the same format, however not compatible. It has been the same since the first release of ByteBoozer1.0. ByteBoozer2.0 and Bitfire (and probably most others today) are searching through *all* possible ways to win bits, where as Bb1.0 has a faster gready algorithm. Remember it was running on the c64 also(!), but that's why B2 compresses better...

...Now i'm very qurious on what new tricks Nucrunch is bringing up to the surface :).


Impressive on the first one doing so well with a native compressor. But yes, I'm doing an exhaustive search too, with the full file rather than a sliding window. I pinched the idea of literals always being followed by matches from Doynax.

Source is out there now (NuCrunch 0.1), but I suspect most of the gains come from a combination of aggressive inlining, and splitting the bitstream into bits, bitpairs, and nybbles, so I can leave out a lot of the 'next byte?' tests.
2016-02-15 08:55
Trash

Registered: Jan 2002
Posts: 122
Quote: Quoting lft
Quoting MagerValp
The trick is to ensure that the compressed stream ends with a match. If it ends with a literal, include the literal data without any control bytes at the correct location.


That is absolutely brilliant!


It is, rather. MagerValp, how were you planning to terminate the stream?

My EOF's over a byte long, and checking end address seems slow if it's not necessarily on a page boundary.


Why use an EOF at all? Inlude how many bytes you should unpack in the header, for speed you could limit that to pages (the tradeoff would be that some data in the end would be overwritten)...
2016-02-15 09:11
Bitbreaker

Registered: Oct 2002
Posts: 500
As already posted earlier, it is sufficient to do any check only in case of a match, be it with an eof marker or by an end address. The check is not more expensive and can even be made without clobbering carry when being done with eor, but takes more size codewise. I have made tests with zero overlap on bitnax, but fail yet on some files with overwriting myself :-/
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