Search found 640 matches

by leonard
Tue Jul 18, 2017 6:42 pm
Forum: Coding
Topic: LZMA - best packing method ?
Replies: 11
Views: 2007

Re: LZMA - best packing method ?

UPX depacks faster than ARJBETA -m7 but has lower compression ratio. ( for instance, We Were @ demo won't fit on two floppies if I use UPX as a packer (I did the test))
If you really want best compression ratio and acceptable depacking speed, use ARJBeta.
by leonard
Thu Jul 13, 2017 11:03 pm
Forum: Coding
Topic: LZMA - best packing method ?
Replies: 11
Views: 2007

Re: LZMA - best packing method ?

For depacking speed of various depacker on various atari machine, you can refer to numbers here: http://www.atari-forum.com/viewtopic.php?f=16&t=31438&p=316491#p316491 (it includes depacker routine size, and packfire tiny and large model .pft and .pfl) Packfire has really good compression ra...
by leonard
Thu Jul 13, 2017 10:52 pm
Forum: Coding
Topic: Screen Pointer Update glitch
Replies: 6
Views: 1247

Re: Screen Pointer Update glitch

And if your frame rate has huge amplitude, you could generalize the algorithm to <n screen buffering> as in famous European demo 3D screen. I think they use 8 screens if I remind well.
by leonard
Sat May 13, 2017 4:12 pm
Forum: Demos
Topic: "We Were @" music
Replies: 7
Views: 3083

Re: "We Were @" music

BenOVR wrote:Do you have a native player for .ym ?


Hi Ben! comment va?

No there is no native YM player on ATARI :( It reminds I started to code one long time ago but never finished. Maybe I can look at my code archive.
by leonard
Sat May 13, 2017 4:09 pm
Forum: Demos
Topic: "We Were @" music
Replies: 7
Views: 3083

Re: "We Were @" music

unfortunately ST-Sound doesn't play it Oh god you're right! I tested the YM file with my XMPlay STSound plugin only! After investigation, StSound95 has a bug when dealing with signed "MIX1" music type! Instead of fixing StSound95 bug, I changed the YM file to unsigned sample data, so it's...
by leonard
Fri May 12, 2017 8:37 pm
Forum: Demos
Topic: "We Were @" music
Replies: 7
Views: 3083

"We Were @" music

Hi everyone! "We Were @" music is made of several sample loops, chained in real time depending of loading time, effect sync etc. Anyway I did a standalone version very close to the demo. It's made from the original loops from Clawz so it's 44Khz, 16bits stereo ( Atari version is downsample...
by leonard
Thu Apr 20, 2017 8:06 pm
Forum: The Digital Department
Topic: 8 channel MODs
Replies: 9
Views: 2298

Re: 8 channel MODs

The ST can too, but with audibly lower quality, You know. Paulo Simoes did a 8 (and even more) channels STF fast replay routine, with the best quality on STF I guess. http://www.pouet.net/prod.php?which=56822 Technical details here: http://www.atari-forum.com/viewtopic.php?f=28&t=20760
by leonard
Mon Apr 17, 2017 7:50 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

DarkLord wrote:Oh, the STacy is an Atari portable (although at its weight, "luggable" might
be a better description!). :)


Oh sorry I missed that! Of course I know Stacy by name, but don't know about the acceleration card. That's really a fast ST!
by leonard
Mon Apr 17, 2017 9:07 am
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

Here's my 40mhz 68030, 40mhz 68882, TOS v3.06 equipped Pak 68/3 STacy. Thanks for these new numbers! I don't know there is some 40Mhz version of TT, but it seems it's a veru fast machine! (does the routine take advantage of FPUs?) not at all BTW, how do you cleanly stop the test? you can't. The ben...
by leonard
Thu Apr 06, 2017 10:24 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

Here's the results from my TT, MSTE and Falcon (3 machines, 3 different monitors, 1 phone ghetto cam so bare with me!) Thanks ggn! It's really interesting. I'm surprised how falcon is "really not so fast" compared to TT or 16Mhz MSTE! I guess your TT is 32Mhz right? it's faster than falco...
by leonard
Thu Apr 06, 2017 10:18 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

latest news: I modify "We Were @" demo installer to use upx --nrv2b, and first floppy won't fit! All screens are bigger than arj -m7! I keep arjbeta -m7 for my demos :) With UPX: 25642 32762 536708 10736 42576 32978 7920 20240 152788 With ARJ -m7 24924 31462 507354 10704 40284 32172 7790 1...
by leonard
Thu Apr 06, 2017 9:28 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

Here is a speed test of nrv2b. The speed is quite impressive for the packing ratio. it's not as good as arj -m7 2 times on 3, but depack speed is x1.5 faster. It's cool for atari demo files PRG because the total time is load_time + depack_time. But in case of demo with trackloader this is not useful...
by leonard
Thu Apr 06, 2017 8:19 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

thanks! I will have a look carefully. I started to disasemble the UPX PRG bootstrap, the depacker is at the end of the PRG and seems really small. It does not contains any huffman-like decoding, that's why it's so fast. The packing ratio is quite good for a non-huffman offset-length coding. I really...
by leonard
Thu Apr 06, 2017 7:25 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

troed wrote:The header+included depack code in those packed PRGs is ~480 bytes in size so should be subtracted I think compared to the other test cases.


you're right! btw do you know where can I extract the packed data only (offset & size) and depacking routine?
by leonard
Thu Apr 06, 2017 7:17 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

I just made a test with upx --nrv2b, it's close to arj -m7. Here are size results: -a---- 01/04/2017 18:32 5560 kernel.l77 -a---- 01/04/2017 18:32 3885 kernel.am4 -a---- 06/04/2017 20:59 3836 kernel.upx -a---- 01/04/2017 18:32 3347 kernel.am7 -a---- 01/04/2017 18:32 3310 kernel.ice -a---- 02/04/2017...
by leonard
Thu Apr 06, 2017 11:57 am
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

The depacker fits in the boot sector, and the depack speed is so fast that I can get away with mostly no background loading in the demo - oh UPX, ok. According to https://sourceforge.net/p/upx/discussion/6805/thread/e7c6e993/ -nrv2b means LZO packing algortihm. LZO is really fast for decompression,...
by leonard
Wed Apr 05, 2017 8:35 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

Cyprian wrote:Is it autostart floppy disk?


it's a trackload demo system with bootsector etc. In case of MegaSTE I activate the cache and set to 16Mhz ( I use move.b #$ff,$ffff8e21.w )

For TT, I don't use TT ram at all ( I even don't know it exist :))
by leonard
Wed Apr 05, 2017 8:16 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

Here is what got on Falcon at 16MHz, caches on (default) thanks for bench! I though falcon would be faster for shk and pfl, really strange. May I ask: why non-standard floppy format, actually why floppy image at all instead nice regular files ? I do all my atari stuff with my own PC toolchain since...
by leonard
Tue Apr 04, 2017 8:55 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

Most of packers used with ST are very slow in depacking some of them are really good and depack as fast as floppy read. ( LH5 and ArjBeta -m7 ). I use these packers in my demos, and the depacking time is free ( I mean it depack at the same time the floppy is reading, and depacking use almost the sa...
by leonard
Tue Apr 04, 2017 7:59 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

Anyone would like to run my depacking test MSA file on other machine than STE? I'm curious to see the timing on Falcon for instance.
by leonard
Mon Apr 03, 2017 8:28 am
Forum: Hardware
Topic: Can anyone explain how the ST determines how much RAM it has on startup?
Replies: 26
Views: 4488

Re: Can anyone explain how the ST determines how much RAM it has on startup?

This is really interesting. I always used very simple test for my demos, but now I wonder if it could report bad state in some cases. For instance, in We Were @ demo I test "4MiB" machine juste by writing a 32bits at $3ffffc and read it back and compare. But, is that possible that $3ffffc ...
by leonard
Mon Apr 03, 2017 8:19 am
Forum: Coding
Topic: YM : Sample and R13 retrig questions.
Replies: 11
Views: 2521

Re: YM : Sample and R13 retrig questions.

Targhan wrote:Well, setting the square frequency to 0 and then to its original value did the trick.


Wow I even don't know that trick myself :) obviously this is not supported by YM STSound format :(
by leonard
Sun Apr 02, 2017 7:48 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

Re: ATARI depacking benchmark

out of curiosity, what packer are you using in {closure}?
by leonard
Sun Apr 02, 2017 6:40 pm
Forum: Coding
Topic: ATARI depacking benchmark
Replies: 35
Views: 5286

ATARI depacking benchmark

Hi, I'm always curious about packing technics and depacking speed. Recently I looked at "shrinkler" wich is a really interesting packer for small data. It use arithmetic coding it's quite slow. So I decide to make a benchmark to look at verious atari depacker speed. I attached the benchmar...
by leonard
Tue Mar 28, 2017 11:22 pm
Forum: 680x0
Topic: about the blitter ^^
Replies: 27
Views: 8216

Re: about the blitter ^^

"actually amiga is really cool piece of hardware, but IMO it was just a game console with a keyboard" It may have been designed as a game console, but if you look at the operating system, it was pretty amazing for the period: doing a full multi-task system using a simple 68000 (no memory p...

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