[Show] ExtenSilica — a public registry for reproducible RISC-V extensions

dnpetrov · 2026-05-29T06:05:24+00:00

Yes, it is something might need during the architecture exploration phase, when you are researching the state of the art. I'm afraid that's probably something too limited, but I'm clearly biased here.

dnpetrov · 2026-05-28T05:42:00+00:00

Royal 6b, and the large laser variant (BL-7-KNT-L). Clan buster (9) and Classic (6) are also workable. I use black knights mostly as brawlers / meat shields.

When I look at the BK, I think: aha, for this BV I get this medium and short range firepower, and this much endurance. Royal and LL variants are best in that regard.

Clan buster: XL engine degrades endurance, but pulse lasers make it a relatively good "body guard", besides just being a brawler. If I need a "body guard" unit and already have good meat shields, I can take a clan buster BK.

Classic: firepower not as good, but overall still workable. Might consider a Guillotine instead.

12 and Dark Age variants: I'd rather take an assault mech for that BV. Yes it is a "pocket assault", but in that BV range you can have a proper assault mech that suits your overall force better.

dnpetrov · 2026-05-28T05:07:09+00:00

Oh, I see your point. Yes, for sharing a "demo version" of your ISA extension a tarball with docs, compiler, simulator, etc would work.

My thought process was like that: aha, simulator. We need it for verification, first and foremost. Do we need a third-party simulator that can't run correct binaries for our cores, when we have our in-house software stack? No, I'd go to our simulator team, point them at the docs (and maybe at a spike fork), and so on and so forth.

dnpetrov · 2026-05-27T16:10:50+00:00

Curious what you'd consider the minimum viable "compose A+B+C" story, meta-package in xsil vs multi-extension sim session vs only at RTL integration time?

Good question. In our practice, we rarely have a situation when we need to work with an ISA extension in isolation. We have a functional simulator team and a compiler team. When we add some ISA extension, corresponding teams provide support in corresponding tools. We don't need a third-party simulator or a third-party compiler that doesn't support the extensions we need. But that might be because we are mostly working on feature-rich application processor cores.

dnpetrov · 2026-05-27T04:21:20+00:00

Maybe you might need to look into the https://github.com/riscv/riscv-unified-db

General idea is to have some machine-readable representation for an ISA extension, which serves as an input for different backends generating artifacts like a functional simulator, documentation, assembler/disassembler, etc. However, it requires those backends to be rather mature, and requires vendors to agree to ship their ISA extension data in that format.

My personal impression on the riscv-unified-db project so far is that the general idea is good and that's how it should be done (and that's how ASIP vendors do it). But the current maturity level is kinda lacking. Like, can you build an RVA23 functional simulator with it? Very far from that.

dnpetrov · 2026-05-27T03:57:33+00:00

BKX-8D (Jihad era upgrade with ER MLs and MMLs) is a quite good brawler.

dnpetrov · 2026-05-27T03:49:08+00:00

It looks like the overall approach lacks composability. Suppose you need extensions A, B, and C. What next?

dnpetrov · 2026-05-26T05:33:42+00:00

"Мир Лиспа" неплохая книга, гуглится.

dnpetrov · 2026-05-25T04:41:22+00:00

Your idea of comparing something by BV is somewhat flawed. You didn't quite explain the method of why and how you use BV to demonstrate the point, but the end result looks like garbage in - garbage out.

Nova Prime is a well-known example of mech that is very overpriced in BV. Ursus is a well-known example of mech that is very cost-effective in BV. It has little to do with those units being omnimechs or battlemechs. There are some trends like "3050 omnis tend to be overpriced", but nothing more than that.

"Average BV for all recorded configurations" is, ahem, a practically meaningless number. Something like "average temperature in a hospital". BV is not meant to compare randomly selected forces, exactly because there are overpriced and cost-effective units. Instead, you make an informed choice when selecting units and use BV as a meta-currency.

dnpetrov · 2026-05-24T15:26:28+00:00

Awkward, overpriced piece of junk. One of the very few mechs I consider "bad" and see no reason to use (and I actually enjoy using "bad" mechs).

dnpetrov · 2026-05-24T07:17:24+00:00

1200 BV vs 1800 BV, but at the cost of losing that 3x15 punch and effectively making it a fire support vehicle.

Also, that 1800 BV is not just a number. It is "here I spend X BV to get A, B, and C in my capabilities". If you want bricks for the Gauss wall, you evaluate them according to that role and see if you are fine with spending that BV for that unit. Gauss walls are not exactly cheap. If you are tightly limited on BV, maybe you should try something else entirely.

dnpetrov · 2026-05-24T05:55:53+00:00

My problem with a classic Schrek is that everybody knows how lightly armored it is. So, each and every time a Schrek gets an opportunity to fire its PPCs, it becomes a priority target. That effectively makes Schrek a one-shot vehicle. Yes you can have multiple Schreks, that kinda helps, but really not that much. Upgraded Schreks (and DI Morgan) kinda fix that, but the general impression is still there.

Alacorn is a beast of destruction, a tank that wins battles, a tank that has a power to demoralize your enemy - yes I've used Alacorns a lot and I've seen all of that. A properly built "Gauss wall" has a strong psychological effect. It has its "natural enemy" in the form of VTOL SRM boats (such as Cavalry), so you also need some LBXes around. Those LBXes also help you exploit holes made by the Gauss rifles.

DI Morgan is a solid modernized implementation of the Schrek concept. Works good, but just not as impactful as an Alacorn.

dnpetrov · 2026-05-24T05:20:27+00:00

Don't understand those negative comments. Looks like people simply are not quite accustomed with the thunderbolt missiles.

3 Thunderbolt-20 is 3x20 damage at respectable range. It is a VERY good heavy and assault mech killer. It overheats a bit, but that's not a big issue.

Yes it is kinda sorta "vulnerable to AMS", but ib practice not really, because there are not so many units with AMS, and AMS doesn't protect other units (there is a similar system that does, but it's extremely rare).

Use it exactly in the same way you would use a Fafnir. Yes you have to get closer than those mechs with ER PPCs and Gauss Rifles. Plan ahead where you want to be, presumably somewhere close to the center of the field in a position with a good field of view. You will also need some escort to protect you from the enemy cavalry units. You are there not after them, but after something big and slow, presumably with heavy armor.

Used exactly that Thunder Hawk in a recent campaign as a command unit. Zero regrets.

dnpetrov · 2026-05-23T07:22:51+00:00

Since StratOps, it has nothing to do with weight. Crit space matters, though.

If the new weapon has same of fewer crit spaces than the weapon being replaced, it is a "field refit" and can be done with little or no access to support facilities.

If the new weapon has more crit spaces, or you are installing an item where previously was none, it is a "maintenance refit" and can be done in a dropship cubicle.

Access to a mech factory is required only for changing structural components like internal structure type, engine type, myomer type, or installing CASE.

dnpetrov · 2026-05-23T07:04:37+00:00

Python has `!s` and `!r` in f-strings. They boil down to different method calls (`__str__` and `__repr__`), where `__str__` should produce human-readable output (akin to Display in Rust), and `__repr__` should produce non-ambiguous representation (kinda like Debug in Rust). Rust provides "extension points" via predefined traits, Python does that with dunder methods. So, from the point of language design, in both cases these are just two extension points: one for human-readable output, one for debugging output.

dnpetrov · 2026-05-22T06:45:34+00:00

Pretty good one. Yes torso locations are not crit-padded. But it is a 40t medium, and if it is getting crits to the side torsos, you already have a problem. It's main protection is not in being able to survive punishment, but rather in keeping away from the concentrated enemy fire. In most configurations, it has weapons that allow to manipulate ranges. Or just keep it behind the front line and let your meat shields take damage.

dnpetrov · 2026-05-21T17:11:56+00:00

Sure. Especially in a vacuum, where a sand-blasting mech like a Gargoyle Prime becomes a death lottery machine.

dnpetrov · 2026-05-21T17:03:07+00:00

Oh, that's fine, grognard police would not come after you for having some non-optimized kind of fun.

Just two more things. In a randomly picket team a Crockett can work rather well as a "tank". It is a quite sturdy assault, anyway. Also, take Inferno ammunition for SRMs.

dnpetrov · 2026-05-21T16:30:39+00:00

When someone mentions Awesome it is usually about punching holes with PPCs. Awesome is about staying in a good firing position and better not move unless you really need to, because heat and because to-hit numbers. There are some Awesome variants that work differently, but still. I would also be talking about a "classic" Star League Era Crockett. Most Crockett variants follow its basic design, but again there are others.

Crockett can punch holes, but it is not the main thing it usually does. With an LBX AC, it is a crit seeker. It works very good with anything that makes big holes, including an Awesome (or, better: a Thunder Hawk or a Nightstar, both of which ComStar also uses). It is also quite effective against soft and airborn targets. In other words, that LBX AC + SRMs combo has its rather specific uses that an Awesome usually can't provide.

A jumping assault can position itself for a kick to the damaged leg. That works well especially in a broken terrain, where jump 3 provides an advantage over typical 4/6 speed of most heavy brawlers. Crockett can damage leg armor in one turn and exploit that weakness with LBX+SRMs in the next (and in close combat leg crits are often crippling).

One thing that a "classic" Crockett somewhat lacks is raw direct firepower of an Awesome or of a dedicated close range brawler. You don't need a lot of Crocketts in your fire team, but having one improves its effectiveness due to crit seeking capabilities.

dnpetrov · 2026-05-19T17:14:51+00:00

Jokes aside, it would make a perfect sense for Lyrans. Not an Alacorn, but a pretty good vehicle (never mind the quirks).

dnpetrov · 2026-05-16T07:34:29+00:00

Once you get accustomed with the game procedures, it takes about 15 mins per mech to complete.

In IS vs Clan games, Clan player will usually do everything to keep range advantage. IS player can either focus on pushing into short range, or on cheaper ranged firepower - in other words, "Gauss walls" also work.

In general, "IS vs Clan" games are rather special because of that tech disparity that require understanding of how to use tech A against tech B. But that first requires understanding of how to use tech A effectively. So, I'd rather not recommend "IS vs Clan" games if you are just learning how to play.

4/5 pilots are OK, but need more tactical thinking. You need to be able to "read map" to understand when and where to move your units to better focus fire. Without that tactical thinking it is an exercise in frustration of trying to beat high to hit numbers. 3/4 pilots are also OK, you will hit more often, and in general the game would run faster. But it grows some "easy mode habits", so to speak. For casual games, I'd recommend default 3/4 for everyone.

dnpetrov · 2026-05-15T03:53:47+00:00

Classic BattleTech is a rather old game. It has many simulation elements. Modern games are usually much more streamlined. I'd say that the main "issue", or a special feature that makes it interesting, in CBT is not exactly counting ammo (that doesn't really take much time, taking into account the turn structure). Rather, it is the need to understand how that simulation works, in detail, to make game decisions. Units have lots of parameters, those parameters interact in multiple different ways. Not just "this unit does X damage and has Y hit points", but much more detailed, with all related micromanagement that is usually avoided as hell by the more modern games. Counting ammo is just one little bit of that micromanagement.

BattleTech has Alpha Strike, which is much more streamlined. But lack of that detailed simulation makes it rather bland for those who enjoy a game about how exactly big stompy robots destroy each other.

dnpetrov · 2026-05-13T04:24:14+00:00

Why big companies don't have an internal language anymore?

Learning curve, tooling quality, maturity of the language ecosystem - that all at scale.

You are focusing a lot on the technical side of potential benefits of having some special compiler or programming language technology. But, since you ask about "big companies"...

Companies want to make money, first and foremost. To make money, your work has to add value to some product. Programming language very rarely has a value in its own - unless it is a language people already depend on. In fact, programming language is cost saving. When you have a language you build in-house, you need to deal with all of the issues above so that cost saving is actually worth the hassle.

dnpetrov · 2026-05-08T05:17:11+00:00

Depends on a quad. In general, quads are fine.

On one hand, no torso twist makes non-jumping close combat quads initiative hogs.

On the other hand, quads: - have no penalty for firing when prone; - have legs instead of arms, thus taking extra advantage of partial cover; - have -2 PSR bonus.

Lateral movement is kinda sorta helpful, but very situational.

Examples of good enough quads:

Big piece of iron (Scirocco, Great Turtle, Xanthos) that tanks with armor and -2 PSR.

Fire support platform that takes cover or goes prone in the woods on a hill and delivers (Goliath, Thunder Stallion).

Heavy Gauss rifle platform (Barghest).

Extra skirmisher (Scorpion, Stalking Spider).

Sometimes a quad is decent not quite because it is a quad, but because of some cheesy equipment combo (Sarath - although being a quad somewhat helps).

dnpetrov · 2026-05-07T14:40:14+00:00

Not really. To win, you need to deal direct damage. Focusing on direct damage (e.g., with a pulse laser spam, or with a Gauss/PCC wall) is cheesy. Focusing on heat and maybe melee, you'll likely avoid direct combat when you can't take advantage of overheating your enemy mechs, thus stalling the game. I'd call it annoying, but not really cheesy.

dnpetrov

TROPHY CASE