Viewing profile — eigenform

Sorry, when talking about things from the hardware's point of view, I'm in the habit of using the word "programmer" to also mean "the compiler"!

Yes, I'm pointing out the fact that the programmer is expected to manage the ALAT, and that these machines do not automatically recover from cases where your advanced loads are inc…

The difference is that this is not the programmer's responsibility in modern machines: instead we bake-in some hardware that watches the online state of the machine and then active…

Additionally, if you look at the changelogs for old ABL, it seems like this policy decision (only supporting for PRO SKUs) has always been implemented in firmware: https://github.c…

Well, the FDIV bug is simpler. AFAICT this whole thing is tied up in the relationship between DVFS, silicon aging, and being able to have guarantees about clock reliability. That s…

afaict part of the messaging behind this quake is about the worry that big Sanriku earthquakes like this might make it easier for the northeast part of the trench to unlock (closer…

No reason that the rate of subduction has to be the same everywhere. Some of the plate boundaries might be moving into each other in different directions too, the coupling between …

The idea here is about maintaining a "path history"! When looking up a register that tracks the "local" history of outcomes for a particular branch, you want to have a hash functio…

please stop posting worthless drivel from your language model, thank you. it really cheapens the meaning of all these fancy words.

ie. marketed as "dense" instead of "efficient"

Probably because it's very likely that both AMD and Intel have had engineers working on this sort of thing for a long time, and they're now deciding to collectively hash out whatev…

I'm not arguing MPX was a good solution, just that it's silly to assume folks designing x86 machines have been totally ignoring developments in that space for the past ten years.

fwiw "knee-jerk reaction to Apple MIE" is not exactly the right characterization of this. MPX existed and faded away, and it's not very surprising that x86-world would wait for som…

I wonder if this is in response to FineIBT trying to figure out what to use as an undefined opcode? Apparently 0xd6 is being reserved as undefined going forward: https://lore.kerne…

Yeah totally. It's really easy to forget about the fact that x86 is abstracting a lot of stack operations away from you (and obviously that's part of why it's a useful abstraction!…

> x86 CALL/RET I wonder if anyone has actually measured what the code size savings from this look like for typical programs, that would be an interesting read. RISC trope is to exp…

didn't realize that since the last time i looked at these docs, seems like they've added lots of nice block diagrams for all the different parts of the machine. neat!

Since everyone is upset about the lack of technical details in the article, I'll try: The takeaway from that paper (imo, afaict) is that guest userspace can influence indirect pred…

Yeah, they wrote a paper about the ALUs too, see: https://ctho.org/toread/forclass/18-722/logicfamilies/Delega... > There are two distinct 32-bit FCLK execution data paths staggere…

Not even true: Arm, Intel, AMD, and most other hardware vendors (who are actively making an effort to support Linux on their parts) actually publish useful[^1] documentation. edit:…

Not surprising considering I haven't seen a programming manual or actual datasheet for these things in the first place. Usually helps if you tell the community how to interact with…

> preventing instructions from issuing seems like too hard of a requirement If this were the case, you could perform SYSCALL in the shadow of a mispredicted branch, and then try to…