ack_complete

20 ms·

271.
by ack_complete 4y ago
I wrote an optimized FFT for fun a while ago and a lot of this is quite familiar. Optimized FFTs are a fascinating field with a long history. I wouldn't recommend writing one from scratch for production instead of using an existing lib
272.
by ack_complete 4y ago
MSVC can sometimes be convinced to emit tail jumps from a switch() if the cases are densely packed and there is an __assume(0) on the default. Unfortunately, it also tends to encode an offset table instead of a jump table on x64, which I ha
273.
by ack_complete 4y ago
This is always deeply frustrating. You quickly get the sense that the person you're talking to hasn't experienced anything beyond simple float loops that are trivial for the compiler to autovectorize, or really bad examples of han
274.
by ack_complete 4y ago
Practically, 68k is far more usable in AT&T syntax than x86. When I used to do PalmPilot development, you could basically write standard 68k asm with just some extra %s sprinkled before registers and as would be fine with it. The x86 AT
275.
by ack_complete 4y ago
Looks like many x86 cores still do rename MXCSR, though Gracemont notably doesn't: https://chipsandcheese.com/2021/12/21/gracemont-revenge-of-t... Note that you wouldn't necessarily need to do a rea
276.
by ack_complete 4y ago
Had to deal with this same issue when I had a program supporting plugins, DLLs compiled with Delphi would turn on all the floating point traps. Took a while to track down what was causing FP faults in comctl32.dll. It got so bad that I had
277.
by ack_complete 4y ago
6502s or 65C02s were used with cache in many Apple II accelerators. Apple licensed one of them for the Apple IIc.
278.
by ack_complete 5y ago
Rosetta 2 only needs to emulate a macOS specific subset of x86-64 user mode. This needs to emulate kernel mode, including paging and the guest OS hosting its own user mode.
279.
by ack_complete 5y ago
TreeSize is a good alternative to WizTree now that it also has MFT scanning. It's a bit slower than WizTree but has more relaxed licensing/pricing.
280.
by ack_complete 5y ago
From the perspective of someone not at Microsoft, it feels like part of the reason it's such a mess is because it's obviously really badly curated, to the point that the Feedback Hub app encourages it. Older versions of the Feedba
281.
by ack_complete 5y ago
Well, segmented memory was a pain in the butt but was useful at the time -- not to mention _way_ less of a pain than bank-switched memory. The applications that I mentioned wouldn't use all of AVX-512, but once you're familiar wit
282.
by ack_complete 5y ago
That's one of the more useful ones! It's effectively a low-precision 4-component dot product feeding into an accumulator, which means it is a building block for larger dot products. Large dot products are very useful both in signa