floooh

v6502r

C2019–2026

floooh / v6502r

v6502r

visual6502 remixed

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6Mentions

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405GitHub stars

REPOSITORY AT A GLANCE

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What it is

visual6502 remixed

GitHub

Where it is used

No documented product use has been verified yet.

What people are saying

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Also in these discussions

mist64/perfect6502 · linked in 2 of the same discussions

Mentioned in the same Hacker News threads. That is not proof they are substitutes.

This week on Hacker News

Nov 7–Nov 14 UTC · Direct repository links and separately labeled related project stories. Indexed through 11/14/2026, 3:56:07 PM UTC.

No direct repository links were found in the indexed HN discussions over the past seven days. Older discussions are available below.

Mentions over time

HN mentions by year6 dated mentions

Observed mentions: 2019-11-09 05:16:43 UTC to 2026-07-24 07:24:39 UTC.

* An incomplete calendar period is marked with an outlined bar. Its count is not directly comparable with a full period.

Counts come from the repository’s dated source evidence. Index cutoff: 2026-11-02 08:16:59 UTC.

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Period	Start (UTC)	End (exclusive, UTC)	Mentions	Submissions	Comments
2019	2019-01-01 00:00:00 UTC	2020-01-01 00:00:00 UTC	1	0	1
2020	2020-01-01 00:00:00 UTC	2021-01-01 00:00:00 UTC	1	0	1
2021	2021-01-01 00:00:00 UTC	2022-01-01 00:00:00 UTC	1	0	1
2022	2022-01-01 00:00:00 UTC	2023-01-01 00:00:00 UTC	0	0	0
2023	2023-01-01 00:00:00 UTC	2024-01-01 00:00:00 UTC	0	0	0
2024	2024-01-01 00:00:00 UTC	2025-01-01 00:00:00 UTC	2	1	1
2025	2025-01-01 00:00:00 UTC	2026-01-01 00:00:00 UTC	0	0	0
2026 (partial)	2026-01-01 00:00:00 UTC	2027-01-01 00:00:00 UTC	1	0	1

What Hacker News says

6 sources

flohofwoe·Jul 24, 2026

Shameless plug: I wrote a 'remix' a couple of years ago over a Christmas break using WASM+WebGL+DearImGui with better rendering performance, integrated assembler and a couple visualization tools (using the visual6502 team's original reverse engineered netlist data, and https://github.com/mist64/perfect6502 as simulation loop): - 6502: https://floooh.github.io/visual6502remix/ - Z80: https://floooh.github.io/visualz80remix/ - 2A03 (this was contributed): https://floooh.github.io/visual2a03remix/ - source code: https://github.com/floooh/v6502r (the simulation generally runs throttled to 1 half-clock-cycle per frame, so don't use it as any sort of benchmark)

In The Visual 6502

mariuz·Dec 10, 2024Submission

Visual6502 and VisualZ80 Remixed

15 points · Open discussion

flohofwoe·Apr 14, 2024

Author here, interesting to see this posted since it's more like a reference manual for Z80 instructions with 'unusual' timings, mostly useful for emulator coders. The followup blog post about the cycle-stepped Z80 emulator is probably more interesting: https://floooh.github.io/2021/12/17/cycle-stepped-z80.html One important note: at the start of the post I'm speculating about why I was seeing some minor differences to a 'real' Z80, it turned out that this speculation was wrong and instead the differences were caused by 'incomplete' netlist simulation code which worked fine for the 6502 but required some tweaks for the Z80, see the comments of this GH issue for details: https://github.com/floooh/v6502r/issues/2. As far as I'm aware the netlist simulation now behaves correctly like a Zilog Z80 (but note that some reverse engineered Z80 clo

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nes like the East German U880 are known to have slightly different undocumented behaviour - which barely matters in practice though). The Z80 and 6502 emulators in https://github.com/floooh/chips are tested against their respective netlist simulations for correct behaviour and timing (all being based on the netlists from http://www.visual6502.org/ and the simulation code from https://github.com/mist64/perfect6502 - which is the simulation from visual6502.org ported from JS to C).

In Getting into way too much detail with the Z80 netlist simulation (2021)

LargoLasskhyfv·Nov 18, 2021

There is now https://github.com/floooh/v6502r as in remixed. Purposedly better, faster, and has Z80, too.

In Megaprocessor – A micro-processor built large (2016)

flohofwoe·May 8, 2020

I (mostly) returned to C a little while ago, and for smaller things I sometimes create the entire application state as a single, big struct that's made of many smaller nested structs, maybe with one or very few "layers" of dynamically allocated data dangling off from the static "root structure" (but only when really needed). A very simple example is an all-in-one application data structure like this: https://github.com/floooh/v6502r/blob/1d2b79ac11d7828b2722b5... This very simple approach has some downsides of course, mostly because C doesn't help much to solve some problems like a more specialized language could (but on the other hand, it also doesn't get in the way much): - Every part of the program sees and is allowed to change everything, so it would be nice to have a simple syntax for fine-grained visibility and access rules (but not

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at all like C++ public/private, more like compile-time read-only and read-write access tokens). - Not much compile- and runtime-protection from code scribbling over neighboring nested structs. - Not much flexibility for dynamic arrays. It would be good to have 3 flavors: (1) compile-time max capacity which can be completely embedded, (2) a runtime max capacity array, which is allocated once but can never grow, and (3) a fully dynamic array which can grow (but maybe never shrink?). Such dynamic arrays should never change their base address, so that memory locations remain stable. - It's not well suited for bigger programs built from many modules. It should be possible to have highly modular program code, but still end up with a single monolithic "root data layout". One great side effect of this approach is that it feels completely natural to not do dynamic memory allocation all over the place (and one of the good features of C is that memory allocation is always very obvious - and thus easy to avoid).

In Show HN: Micro-mitten – Research language with compile-time memory management

NobodyNada·Nov 9, 2019

The MOS 6502 [0] was an 8-bit CPU that powered many systems from the 70’s and 80’s, including the Atari game consoles, Commodore 64, Nintendo Entertainment System, and early Apple computers. It could also be considered the ancestor of the ARM architecture. Visual 6502 [1] is a transistor-level simulation of the 6502, written in JavaScript. It allows you to investigate how the real hardware behaves in response to some input, and it makes it possible to investigate the circuitry responsible for this behavior. It has proven an invaluable resource in recent years for developers and emulator authors to nail down and document all the weird quirks of their 6502-based hardware. The simulator core is also very useful for modeling other 80’s hardware, such as the NES’s video and audio systems. Looking at this project’s GitHub [2], it appears this i

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s a rewrite of Visual 6502 that compiles into WebAssembly, resulting in vastly improved performance compared to the original JS implementation. [0]: https://en.wikipedia.org/wiki/MOS_Technology_6502 [1]: http://www.visual6502.org/JSSim/index.html [2]:https://github.com/floooh/v6502r

In Visual6502 Remix