Hacker News: em3rgent0rdr

New comment by em3rgent0rdr in "XOR'ing a register with itself is the idiom for zeroing it out. Why not sub?"

em3rgent0rdr — Wed, 22 Apr 2026 13:53:49 +0000

With more bits, then SUB is going to be more and more expensive to fit in the same number of clocks as XOR. So with an 8-bit CPU like Z80, it probably makes design sense to have XOR and SUB both take one cycle. But if for instance a CPU uses 128-bit registers, then the propagate-and-carry logic for ADD/SUB might take way much longer than XOR that the designers might not try to fit ADD/SUB into the same single clock cycle as XOR, and so might instead do multi-cycle pipelined ADD/SUB.

A real-world CPU example is the Cray-1, where S-Register Scalar Operations (64-bit) take 3 cycles for ADD/SUB but still only 1 cycle for XOR. [1]

[1] https://ed-thelen.org/comp-hist/CRAY-1-HardRefMan/CRAY-1-HRM...

New comment by em3rgent0rdr in "Data centers are transitioning from AC to DC"

em3rgent0rdr — Wed, 25 Mar 2026 04:33:58 +0000

Some old guitar effects used -9V DC.[1] And the convention with guitar effects power adapter is the barrel is center negative (which is motivated with facilitating easy wiring of the socket's switch to connect to a 9V battery inside).

[1] https://www.analogisnotdead.com/article26/what-is-going-on-w...

New comment by em3rgent0rdr in "curl > /dev/sda: How I made a Linux distro that runs wget | dd"

em3rgent0rdr — Tue, 24 Mar 2026 17:28:43 +0000

> "download a pre-prepared disk image directly to your disk"

Well not quite direct; the bits go through your RAM in between.

New comment by em3rgent0rdr in "Plasma Bigscreen – 10-foot interface for KDE plasma"

em3rgent0rdr — Sat, 07 Mar 2026 03:24:09 +0000

Too bad can't access $CorpStreamingVideoService full-resolution on linux :(

New comment by em3rgent0rdr in "Show HN: RetroTick – Run classic Windows EXEs in the browser"

em3rgent0rdr — Fri, 27 Feb 2026 16:28:06 +0000

Impressive. Noting however that double-clicking is not working in Minesweeper. :)

Quick Share compatibility with AirDrop expanding to more Pixel devices

em3rgent0rdr — Mon, 23 Feb 2026 16:55:07 +0000

Article URL: https://support.google.com/pixelphone/thread/409524163/quick-share-compatibility-with-airdrop%C2%AE-expanding-to-more-pixel-devices?hl=en

Comments URL: https://news.ycombinator.com/item?id=47124929

Points: 1

# Comments: 0

New comment by em3rgent0rdr in "Can a Computer Science Student Be Taught to Design Hardware?"

em3rgent0rdr — Tue, 17 Feb 2026 18:48:13 +0000

That curricula is often more specifically called "Computer Engineering". CS students meanwhile usually aren't bothered by anything below the compiler.

New comment by em3rgent0rdr in "Can a Computer Science Student Be Taught to Design Hardware?"

em3rgent0rdr — Tue, 17 Feb 2026 18:35:49 +0000

> "CS majors could be taught to design hardware, and the EE curriculum"

"Electrical and Computer Engineering" (ECE) departments already exist and already have such a major: "Computer Engineering".

New comment by em3rgent0rdr in "Ring owners are returning their cameras"

em3rgent0rdr — Fri, 13 Feb 2026 07:20:59 +0000

Stallman was right.

New comment by em3rgent0rdr in "FOSDEM 2026 – Open-Source Conference in Brussels – Day#1 Recap"

em3rgent0rdr — Sun, 01 Feb 2026 14:45:23 +0000

It's about the friends you make when collecting stickers.

New comment by em3rgent0rdr in ""Anyone else out there vibe circuit-building?""

em3rgent0rdr — Mon, 19 Jan 2026 20:06:29 +0000

It depends. Many modern microcontrollers are perfectly fine driving LEDs directly off IO pins if the pin specs say it is rated for sufficient current (like 20mA). However, older ones like ESP8266 can only do like 2mA and the 8051 even less. Or you run into a total power budget issue if your are running too many pins. Also, some IO pins are perfectly fine at sinking current to ground but aren't suited for sourcing current, in which case the LED would be directly connected to an external high voltage and the IO pin would simply be switching to ground or not.

New comment by em3rgent0rdr in "C Is Best (2025)"

em3rgent0rdr — Tue, 06 Jan 2026 15:59:11 +0000

When C code is run in machines capable of failing with gruesome death, its unsafeness may indeed result in gruesome death.

New comment by em3rgent0rdr in "Linux is good now"

em3rgent0rdr — Thu, 01 Jan 2026 21:41:18 +0000

I don't think the prevalence of these articles this time of year is because the authors go on holiday, but instead is because the new year is the perfect time to ponder: "Will this be the year of the Linux desktop?"

New comment by em3rgent0rdr in "Ultra-Low-Latency Trading System"

em3rgent0rdr — Thu, 25 Dec 2025 16:59:43 +0000

Why can't these posts just say "microsecond" instead of the vague and misleading "ultra-low"?

New comment by em3rgent0rdr in "Qt, Linux and everything: Debugging Qt WebAssembly"

em3rgent0rdr — Tue, 09 Dec 2025 22:22:19 +0000

Very useful. It would be great for the browser become the cross-platform application target. I've been eagerly waiting for Qt WebAssembly to mature.

New comment by em3rgent0rdr in "The stack circuitry of the Intel 8087 floating point chip, reverse-engineered"

em3rgent0rdr — Tue, 09 Dec 2025 20:10:15 +0000

Looking at the complexity and area of hardware floating point, I often wonder why we don't see more unified combined integer+floating point units, like done in the R4200 [1], which reused most of the integer datapath while just adding a smaller extra smaller 12-bit datapath for the exponent.

[1] https://en.wikipedia.org/wiki/R4200

Married millennials, here comes the crypto divorce cliff

em3rgent0rdr — Mon, 08 Dec 2025 07:23:06 +0000

Article URL: https://www.cnbc.com/2025/12/07/millennials-bitcoin-crypto-divorce-law.html

Comments URL: https://news.ycombinator.com/item?id=46189380

Points: 9

# Comments: 0

New comment by em3rgent0rdr in "Tiny Core Linux: a 23 MB Linux distro with graphical desktop"

em3rgent0rdr — Sun, 07 Dec 2025 13:39:08 +0000

If you use a tile-based hardware renderer, such as on the original nintendo chip, then pixels are rendered on the fly to the screen by the hardware automatically pulling pixels based on the tile map.

New comment by em3rgent0rdr in "Cursed circuits: charge pump voltage halver"

em3rgent0rdr — Wed, 03 Dec 2025 05:18:03 +0000

The '7660 is good for low-power and is my go-to DIP-8 part when I need a half or double voltage supply on a breadboard.

New comment by em3rgent0rdr in "DOOM could have had PC Speaker Music"

em3rgent0rdr — Wed, 03 Dec 2025 04:38:17 +0000

id Software should have just partnered with a heavy metal band that jointly released an album of Doom music you could put in your stereo while you play the game.