YASEP news

The main YASEP site has not been updated for a while...
Worse : the f-cpu.seul.org miror is down since january !

Is the project dead ?

No :-)

In fact a lot of things are being prepared, mostly in the commercial, infrastructure and very-low-level hardware (like : where are those 0402 capacitors ?) fronts. It's really exciting but it takes a lot of time and money ! Fortunately I'm not completely alone.

A string of good news will probably come in 2011, they will help the bootstrap of the whole YASEP project with different kinds of support, with broad public exposure. It will be possible to have a YASEP implementation in hand, I work both on the hardware and software sides :-) BTW, a recent Wikipedia article has appeared with a short summary of the YASEP's architecture.

Another critical part of the project (the VHDL source code and its infrastructure) is in active development : GHDL is now the officially supported simulator. I have interviewed the main developer (Tristan Gingold) for GNU/Linux Magazine France n°127. With Laura, we started a series of articles about VHDL development under Linux and I am proposing increasingly advanced ... hacks :-) The first YASEP implementations will be designed with "design for test" in mind.

In parallel, another subproject is the design of a Libre, affordable, compact and Ethernet-enabled JTAG programming probe. More on this subject in the future, but it's critical for the rest of the whole project : my JTAG probes are either USB (and constrained to Actel parts, and don't work under Linux) or parallel-port (no new consumer-grade computer today has this port anymore).

Finally, after the seul.org debacle (due to main server being compromised because of its participation in the tor network), I have opened a new miror at TuxFamily.

So I'm still polishing the tools and gathering the parts. It's not a visible activity but it's probably the most important. What does an architecture mean if there is no infrastructure behind ? With no physical implementation that one can buy and hack oneself ?

Grâce au concours de Laura, une partie des pages web du site YASEP est en cours de traduction en français. Pour l'instant, ont été intégrées les pages suivantes : l'index, les registres, les instructions, la carte interactive des opcodes et YASEP16/32. D'autres pages devraient suivre, j'attends que Laura soumette d'autres pages.

Au début du projet, j'avais décidé de tout faire uniquement en anglais. Mon expérience m'a montré que le support de plusieurs formats ou langues différentes augmente la charge de travail, donc réduit le temps passé à créer des choses utiles. De plus, il y a toujours une version qui est à la traine et cela rend le projet incohérent, vu de l'extérieur. On a alors tendance à ne plus se référer qu'à la version "principale" (en anglais) et la version traduite sombre dans l'inutilité.

Ce coup-ci, il est bien clair que la version "officielle" du projet est en anglais. La traduction française sera probablement en retard sur un nombre inconnu de points, à mesure que le temps passe. Mais la démarche de traduction apporte plusieurs avantages :

* D'abord, j'ai tendance à écrire en anglais de manière absconse et à la fin je suis le seul à comprendre ce que j'ai écrit. La traduction me confronte à mes mauvaises manies et m'oblige à reformuler mes phrases, pour les rendre plus claires. C'est en accord avec mon exigence d'accessibilité, d'autant plus que la traductrice, Laura, est moins bonne en anglais et en technique que moi, et je voudrais être compris par des personnes encore plus débutantes.

* Ensuite, Laura est plus proche et plus exigente que les collaborateurs précédents. J'en attends une meilleure qualité et un meilleur suivi.

* Aussi, avoir deux versions d'une même page web force à séparer la présentation, le contenu et les scripts : c'est la nécessité de modularité et de non-redondance qui deviennent importants.

En plus, cela me permet de revoir et donc améliorer les pages originales, d'y faire du tri...

Comme d'habitude, je suis intéressé par toute remarque constructive pour améliorer le site.

Development of and around YASEP is going on in a weird way, but it still continues...

Why so much caution ? Because the changes to the architecture are quite deep. The instructions forms are increasingly complex and I've pushed the design beyond what I intended in the beginning.

If you don't remember, YASEP had only two ways to address data previously :

short form :

 Reg1 OP Reg2 => Reg1  (16 bits)

long form :

  Reg1 OP Imm16 => Reg2 (32 bits)

Now a few bits are freed and this gives much more "flexibility", so I added :

Short Immediate :

  Reg1 OP Imm4 => Reg1 (16 bits)

Long Register :

  Reg1 OP Reg2 => Reg3 (32 bits)

And because there was still some room, this last form has more elaborate versions :

Long conditional :

  Reg1 OP Reg2 IF{NOT} Reg4{LSB/MSB/Zero/ready} => Reg3 (32 bits)

And other versions come up when the Reg2 field is interpreted as Imm4 :

Long conditional short Imm: (excuse the name)

  Reg1 OP Imm4 IF{NOT} Reg4{LSB/MSB/Zero/ready} => Reg3 (32 bits)

Or without condition :

  Reg1 OP Imm4 => Reg3 (32 bits)

This applies to the computation instructions, the control instructions are still too undefined yet.

Code density should increase, which is worth the efforts. I don't know if it will reach the level of ARM or x86 but it is certainly a major advance. However, this breaks a lot of the assembler's mechanisms, so I prefer to rewrite it. This takes a while because the rest must be adapted too : the Instruction Set, the manual pages, the validators...

If you can't stand the wait, have a look at a precent, broken version at http://yasep.org/~whygee/yasep2009/, at least it is more recent than the main site.

I recently got 3 colibri boards ! When you think about Italy, you think Ferrari and other excellent things, now I'll also think prototyping boards ;-)

Thanks to ACME systems, I bought 2* A3P250 and one A3P1000 boards for a friendly price. These are pre-series units and may slightly differ from later versions, but they are really as cool as the pictures let you think.

The website is also updated : the JavaScript engine is now mostly functional for YASEP16 and YASEP32 versions. The documentation is not updated and many dark corners remain in the architecture definition. I have chosen to publish the latest versions, since I don't know when I'll do this next time.

This is my first "blog" so please be forgiving !

Well in fact, it's the first time that i see the interest in such a "communication medium". So here you'll find comments on the latest updates in the YASEP project. Recently :

• I just moved the yasep.org/com DNS to "our" new shiny server at http://92.243.8.20 , leaving the old site http://f-cpu.seul.org/whygee/yasep/ untouched. It's not that I dislike seul.org (I thank the Moria team heartfully) but some independence can be good. And mirroring, too.

• I also corrected some strange behaviour with Firefox 3, nothing critical.

• But more importantly, i'm waist-deep into VHDL, netlists, synthesis and P&R with my recently acquired Actel evaluation board ! \o/ I've been busy during the whole month of july on the subject of a pipelined 32-bit add/sub execution unit.

And I have many other things in store, and so little time to do them...

Finally, thanks to my dearly loved geekette for hosting me :-)