HNHacker News
TopNewBestAskShowJobs

pechay

68 karma · joined June 26, 2013

submissionscomments
pechay··on Microcode in Intel's 8087 floating-point chip: the scale instruction
Great work! I love to read your articles.

I'm curious to know - you say Intel's 8087 emulation code was a bit of a lump at 16KB, do you know if it emulated the 8087 microcode state machine or did it use a different strategy?

pechay··on Writing a (valid) C program without main()
All C programs are interesting. The first potentially non-interesting program in C is interesting because it's the first non-interesting one. :)
pechay··on A brief history of threads and threading
It's worth pointing out the Commodore Amiga had proper pre-emptive multitasking on a single M68000 all the way back in July '85
pechay··on Show HN: I recovered one of my earliest ZX-Spectrum games from an audio cassette
Thank you for your incredibly detailed correction :)
pechay··on Show HN: I recovered one of my earliest ZX-Spectrum games from an audio cassette
The ZX Spectrum ROM loader is 1500bps and some games loaded at over 3000. There wasn't any encoding, just straight-up 1s and 0s straight into RAM.
pechay··on Reciprocal Approximation with 1 Subtraction
The 68k has both signed and unsigned 32/16 bit divide instructions.
pechay··on In 1870, Lord Rayleigh used oil and water to calculate the size of molecules
We did this same experiment in school, with a tiny pinprick of oil, estimating the volume of the drop as a sphere, and a small water tank, and then estimated the area of oil slick as a circle.
pechay··on Qubit Transistors Reach Error Correction Benchmark
University of New South Whales!
pechay··on Ford F-150 Lightnings will soon offer home AC power, possibly cheaper than grid
If everyone starts using cheap off-peak power, will it continue to be cheap?
pechay··on Amiga Graphics Archive
The Amiga didn't have any hardware assistance for scaling sprites, so almost certainly the former.
pechay··on Linear code is more readable
pizza isn't, and can't be, opaquely modified by the topping adder this way.
pechay··on Linear code is more readable
I don't like the side effects of the second addToppings. I'd much prefer

pizza.Toppings = getToppings(kind string)

pechay··on Living in Airbnbs full time isn’t easy (2021)
I've stayed in over fifty Airbnb in the last three years. Only three haven't worked out (misleading apartment, mouse-poop kitchen, unresponsive host). Each time Airbnb has sorted me out with a refund, called me to discuss the problem, helped finding an alternative place, and providing a voucher to cover any price gap.
pechay··on Ask HN: Did Anyone Else Here Simply Not Do Well at School?
If you're certain it's what you want, don't accept no for an answer and keep hassling the school or college at different levels and see if you can still make it happen.
pechay··on Why Self-Checkout Is and Has Always Been the Worst
Do you ever buy alcohol?
pechay··on Retro Computer Museum
The RCM is fantastic, definitely worth a visit, and Andy who runs the place is a legend.
pechay··on Merge branch 'x86-rep-insns': x86 user copy clarifications
I think unrolled FILD/FIST was fastest on Pentium.
pechay··on Ask HN: What is the best product documentation you’ve ever seen?
Similarly, the manual that came with the original ZX Spectrum rubber key version was awesome, with a complete description of Sinclair BASIC and all the Z80 assembler op codes for good luck. The 48k+ manual that followed was nowhere near as useful.
pechay··on A SVB short seller explains red flags he saw months ago
Disable JavaScript also works.
pechay··on Ask HN: How to negotiate shares at my new job?
Make sure you are paid and bonused properly regardless of any future exit, because most startups never get there. In CTO role you should get something at the exit too, because you are likely to be instrumental in that success. Because companies often pivot or your part of the company changes outside of your control, you should have both.
pechay··on Why is C slower than Bolin?
You are comparing file IO, string to int, raw processing, and text output speed all at the same time. There are pros and cons associated with the choices made in both sets of libraries and compilers for each of those aspects. What exactly are you trying to measure? Can you isolate those parts more specifically and compare them instead? That would probably be more informative.
pechay··on Ask HN: New job at BigCo. Everything has friction
Explore the limits of your responsibility and find out where you can make your life easier. Find allies in other parts of the business; politics are a fact of life in any big business. Carefully choose which hills are worth fighting for.
pechay··on 3 lines of code shouldn't take all day
Aside from looking at changes in your dev methods, this is a good way to demonstrate to your management the value of having fast, up to date hardware on your desk.
pechay··on Ask HN: Advice for moving on from a failed startup?
If OP wants to work abroad in the future - where I come from getting a skilled visa having a degree is an advantage. Not having a degree is not a problem either. But trying to get a visa having dropped out definitely counts against you.
pechay··on Username ending with MIME type format is not allowed
Once had my Australian production system go down because a js plugin we were using had added .au to its list of media types. Integration had a different TLD. Response I got from the author was 'LOL!'. :)
pechay··on Prevent duplicate cron job running
The other solutions based on file locking tools all seemed fragile. You have to change _something_!
pechay··on Prevent duplicate cron job running
Add and verify a last_started and last_completed time to your local database.
pechay··on I converted my demoscene font collection to PNG and put it on GitHub
It is almost compulsory for a demo scrolltext to include "greets" to other demo groups and members and "f*kings" to those you don't like or have done something lame. Very useful to have a special symbol for that!
pechay··on Does register selection matter to performance on x86 CPUs?
1. MOV AL, BYTE PTR [RDI]

MOV EBX, EAX // partial register stall

2. MOVZX EAX, BYTE PTR [RDI]

AND EAX, 0xFFFFFF00

MOV EBX, EAX // no partial register

These don't do the same thing

pechay··on My Favorite Programming Problem to Teach: Digit Length
Must be a good teaching problem seeing as it's generated such a large amount of interesting discussion.
Page 1 of 2Next →