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Apple facing huge chip patent bill after losing case

bbc.com

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Re: Apple facing huge chip patent bill after losing case

#21
Looks like the "idea" of the patent in the description is to use a predictor to predict when a STORE and LOAD alias and not speculate the LOAD and any instruction depending on the load (although the claims generalize this to any non-static dependency).

As it generally happens in software/hardware patents, the claimed solution seems quite obvious whenever one wants to solve that particular problem, and the hard part is the "execution", i.e. implementing it efficiently and figuring out whether the tradeoffs are worth it.

So assigning patents to things like this seems really dumb.

Re: Apple facing huge chip patent bill after losing case

#24
post #19
post #12

You know what they say: Live by the patent sword... Why doesn't Apple start lobbying for real patent reform?

Because it makes no sense for them to do so. Large companies join in cross-licensing agreements, keeping smaller competitors out. Occasionally some small player comes along with an important patent, and they refuse to be bought off and win in court. That makes the news like today because it happens so rarely. But it's a price worth paying to keep competition out of the market. Competition is so tedious.

This isn't a small company with a new idea that doesn't want to be bought out, this is an university.

Re: Apple facing huge chip patent bill after losing case

#25
post #5

Earlier quoted context omitted.

If it's $862m, last I checked, it will take them about 30 hours to bring in the necessary revenue--if they want to pay out of profits (I'm totally guessing here, what are real net margins on their hardware? 15-20%?), it'll take a couple days.

Man, that's such a humbling stat. Many of us here don't even earn that in a year !

We're also talking about one of the largest companies in the world, so it's really not that shocking.

Re: Apple facing huge chip patent bill after losing case

#26

Earlier quoted context omitted.

Bear in mind the patent was filed in 1996 when considering the level of innovation.

There were branch-predicting mainframes back in the 80s, though it really came to the fore with the advent of superscalar microprocessors in the early 90s (MIPS R8000 and DEC Alpha 21064), what is the paper's innovations above these?

It's pretty clear from even a cursory look – the patent covers a second level of branch prediction, where the processor determines whether or not it should bother speculatively executing an instruction based on the previous outcome of that speculative execution.

Whether or not there was a prior implementation of this, I don't know – but it's also obviously more than a simple saturating counter branch predictor or whatever.

Re: Apple facing huge chip patent bill after losing case

#27

Earlier quoted context omitted.

Man, that's such a humbling stat. Many of us here don't even earn that in a year !

$862 million? > Man, that's such a humbling stat. Many of us here don't even earn that in a lifetime ! FTFY Unless I missed the /s ;)

Even more exaggerated than that. Many families don't earn that across several generations. That's about 17,000 years at $50,000/year. At 40 years of working life, you'd need over 400 people.

Re: Apple facing huge chip patent bill after losing case

#28

$862m isn't that huge in the grand scheme of things. Not to mention, it's most likely not going to be $862m, my guess is it'll be less.

It's more than double what Apple paid for P.A. Semi and Intrinsity put together, the fabless semiconductor design firms that are the foundation of Apple's processor engineering capabilities.

Re: Apple facing huge chip patent bill after losing case

#29
This PDF explains what I discuss below in more detail: http://moodle.technion.ac.il/pluginfile.php/315285/mod_resou.... Prediction of aliasing is discussed on slide 25.

The patent in question pertains to an optimization of what these days you'd call "memory disambiguation." In a processor executing instructions out of order, data dependencies can be known or ambiguous. A known data dependency is, for example, summing the results of two previous instructions that themselves each compute the product of two values. An ambiguous data dependency is usually a memory read after a memory write. The processor usually does not know the address of the store until it executes the store. So it can't tell whether a subsequent load must wait behind the store (if it reads from the same address), or can safely be moved ahead of it (if it reads from a different address).

If you have the appropriate machinery, you can speculatively execute that later load instruction. But you need some mechanism to ensure that if you guess wrong--that subsequent load really does read from the same address as the earlier store--you can roll back the pipeline and re execute things in the correct order.

But flushing that work and replaying is slow. If you've got a dependent store-load pair, you want to avoid the situation where misspeculation causes you to have to flush and reply every time. The insight of the patent is that these dependent store-load pairs have temporal locality. Using a small table, you can avoid most misspeculations by tracking these pairs in the table and not speculating the subsequent load if you get a table hit. That specific use of a prediction table is what is claimed by the patent.

Maybe this is worth a patent, or maybe not. For what it's worth, I don't think anybody was doing memory disambiguation at all in 1996. Intel was one of the first (maybe the first) to do so commercially in the mid-2000's. Apple's Cyclone architecture also does it, and I think it was the first in the low-power SoC space to do it.

Re: Apple facing huge chip patent bill after losing case

#30

Earlier quoted context omitted.

Man, that's such a humbling stat. Many of us here don't even earn that in a year !

We're also talking about one of the largest companies in the world, so it's really not that shocking.

And Apple saves a lot of money by not paying taxes /s
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