Skip to content
By using Twitter’s services you agree to our Cookies Use. We and our partners operate globally and use cookies, including for analytics, personalisation, and ads.

This is the legacy version of twitter.com. We will be shutting it down on June 1, 2020. Please switch to a supported browser, or disable the extension which masks your browser. You can see a list of supported browsers in our Help Center.

  • Home Home Home, current page.
  • About

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @
  • Language: English
    • Bahasa Indonesia
    • Bahasa Melayu
    • Català
    • Čeština
    • Dansk
    • Deutsch
    • English UK
    • Español
    • Filipino
    • Français
    • Hrvatski
    • Italiano
    • Magyar
    • Nederlands
    • Norsk
    • Polski
    • Português
    • Română
    • Slovenčina
    • Suomi
    • Svenska
    • Tiếng Việt
    • Türkçe
    • Ελληνικά
    • Български език
    • Русский
    • Српски
    • Українська мова
    • עִבְרִית
    • العربية
    • فارسی
    • मराठी
    • हिन्दी
    • বাংলা
    • ગુજરાતી
    • தமிழ்
    • ಕನ್ನಡ
    • ภาษาไทย
    • 한국어
    • 日本語
    • 简体中文
    • 繁體中文
  • Have an account? Log in
    Have an account?
    · Forgot password?

    New to Twitter?
    Sign up
pcwalton's profile
Patrick Walton
Patrick Walton
Patrick Walton
@pcwalton

Tweets

Patrick Walton

@pcwalton

Research engineer at Mozilla

San Francisco, CA
pcwalton.github.io
Joined November 2009

Tweets

  • © 2020 Twitter
  • About
  • Help Center
  • Terms
  • Privacy policy
  • Imprint
  • Cookies
  • Ads info
Dismiss
Previous
Next

Go to a person's profile

Saved searches

  • Remove
  • In this conversation
    Verified accountProtected Tweets @
Suggested users
  • Verified accountProtected Tweets @
  • Verified accountProtected Tweets @

Promote this Tweet

Block

  • Tweet with a location

    You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more

    Your lists

    Create a new list


    Under 100 characters, optional

    Privacy

    Copy link to Tweet

    Embed this Tweet

    Embed this Video

    Add this Tweet to your website by copying the code below. Learn more

    Add this video to your website by copying the code below. Learn more

    Hmm, there was a problem reaching the server.

    By embedding Twitter content in your website or app, you are agreeing to the Twitter Developer Agreement and Developer Policy.

    Preview

    Why you're seeing this ad

    Log in to Twitter

    · Forgot password?
    Don't have an account? Sign up »

    Sign up for Twitter

    Not on Twitter? Sign up, tune into the things you care about, and get updates as they happen.

    Sign up
    Have an account? Log in »

    Two-way (sending and receiving) short codes:

    Country Code For customers of
    United States 40404 (any)
    Canada 21212 (any)
    United Kingdom 86444 Vodafone, Orange, 3, O2
    Brazil 40404 Nextel, TIM
    Haiti 40404 Digicel, Voila
    Ireland 51210 Vodafone, O2
    India 53000 Bharti Airtel, Videocon, Reliance
    Indonesia 89887 AXIS, 3, Telkomsel, Indosat, XL Axiata
    Italy 4880804 Wind
    3424486444 Vodafone
    » See SMS short codes for other countries

    Confirmation

     

    Welcome home!

    This timeline is where you’ll spend most of your time, getting instant updates about what matters to you.

    Tweets not working for you?

    Hover over the profile pic and click the Following button to unfollow any account.

    Say a lot with a little

    When you see a Tweet you love, tap the heart — it lets the person who wrote it know you shared the love.

    Spread the word

    The fastest way to share someone else’s Tweet with your followers is with a Retweet. Tap the icon to send it instantly.

    Join the conversation

    Add your thoughts about any Tweet with a Reply. Find a topic you’re passionate about, and jump right in.

    Learn the latest

    Get instant insight into what people are talking about now.

    Get more of what you love

    Follow more accounts to get instant updates about topics you care about.

    Find what's happening

    See the latest conversations about any topic instantly.

    Never miss a Moment

    Catch up instantly on the best stories happening as they unfold.

    1. isis agora lovecruft (they/them)‏ @isislovecruft 18 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      omg it’s real i can undress tony david in sixteen glorious bits of pixelated colour i can’tpic.twitter.com/VqEBS9WIbV

      4 replies 6 retweets 72 likes
      Show this thread
    2. isis agora lovecruft (they/them)‏ @isislovecruft 18 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      f r i e n dpic.twitter.com/3sz4qQ8VXO

      5 replies 0 retweets 61 likes
      Show this thread
    3. isis agora lovecruft (they/them)‏ @isislovecruft 18 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      it’s alivepic.twitter.com/R1zGzvh90L

      7 replies 2 retweets 34 likes
      Show this thread
    4. isis agora lovecruft (they/them)‏ @isislovecruft 18 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      oh my god some wonderful person labelled each end of this a/v cable with a typewriterpic.twitter.com/ZKqh0B7Cds

      2 replies 4 retweets 66 likes
      Show this thread
    5. isis agora lovecruft (they/them)‏ @isislovecruft 18 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      oh noooo i need another video cable [to be continued…]

      3 replies 0 retweets 8 likes
      Show this thread
    6. isis agora lovecruft (they/them)‏ @isislovecruft 19 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      been learning valuable 6502/6510 assembly tricks like "the easiest way to multiply on the 6502 is to not do it at all" (there's no MUL instruction)pic.twitter.com/KJXvepvMDL

      somebody on the internet explaining why not having a MUL instruction on a chip is somehow ok
      2 replies 1 retweet 11 likes
      Show this thread
    7. isis agora lovecruft (they/them)‏ @isislovecruft 19 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      the 6502 architecture has Super Fucky instructions in the zero-page indirect addressing mode EOR ($13),Y adds an 8-bit value (say $06) in register Y to the 16-bit address (say $C864) at $0013-14 to produce address $C870 then exclusive-ORs the value at $C870 into the accumulatorpic.twitter.com/icLk9WNJ9V

      6502 opcode matrix with addressing modes
      an ancient diagram of 6502 registers and opcodes for transfering between them, which is slightly ajar due to the PDF it was taken from being a bad scan of a very old programming book
      2 replies 1 retweet 4 likes
      Show this thread
    8. isis agora lovecruft (they/them)‏ @isislovecruft 19 Apr 2018
      • Report Tweet
      • Report NetzDG Violation

      the commodore 64 provides ARGaaS (Accidental ROP Gadgets as a Service) w h a t c o u l d g o w r o n gpic.twitter.com/Cz7Ld0bgoz

      AN INDIRECT JUMP MUST NEVER USE A
VECTOR BEGINNING ON THE LAST BYTE
OF A PAGE

For example if address $3000 contains $40, $30FF contains $80, and $3100 contains $50, the result of JMP ($30FF) will be a transfer of control to $4080 rather than $5080 as you intended i.e. the 6502 took the low byte of the address from $30FF and the high byte from $3000.
      2 replies 4 retweets 25 likes
      Show this thread
    9. Patrick Walton‏ @pcwalton 19 Apr 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @isislovecruft

      Well, no memory protection means that ROP isn’t needed anyway :) Check out the 6502 invalid ops sometime. They’re pretty awesome…

      1 reply 0 retweets 0 likes
    10. isis agora lovecruft (they/them)‏ @isislovecruft 19 Apr 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @pcwalton

      right, but it’s super entertaining that what looks like a sane instruction will do something entirely different! an obfuscated 6502 competition would sure be interesting! do you mean the opcodes where the lower nybble is 3/5/B/F? like the undefined ones?

      1 reply 0 retweets 0 likes
      Patrick Walton‏ @pcwalton 19 Apr 2018
      • Report Tweet
      • Report NetzDG Violation
      Replying to @isislovecruft

      Yup! Here’s a document of them: http://www.ffd2.com/fridge/docs/6502-NMOS.extra.opcodes …

      5:57 PM - 19 Apr 2018 from Civic Center, San Francisco
      • 3 Likes
      • Matt zach wick isis agora lovecruft (they/them)
      2 replies 0 retweets 3 likes
        1. isis agora lovecruft (they/them)‏ @isislovecruft 19 Apr 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @pcwalton

          woaaaah! thank you this is amazing there's undocumented combinations between bitwise operations that are less cycles to execute this is the best

          0 replies 0 retweets 2 likes
          Thanks. Twitter will use this to make your timeline better. Undo
          Undo
        1. Ashley‏ @khyperia 19 Apr 2018
          • Report Tweet
          • Report NetzDG Violation
          Replying to @pcwalton @isislovecruft

          "This happens very infrequently. The behaviour appears to be connected with the video display. For example, it never seems to occur if either the screen is blanked or C128 2MHz mode is enabled." ❤️❤️❤️!!!!!

          0 replies 0 retweets 2 likes
          Thanks. Twitter will use this to make your timeline better. Undo
          Undo

      Loading seems to be taking a while.

      Twitter may be over capacity or experiencing a momentary hiccup. Try again or visit Twitter Status for more information.

        Promoted Tweet

        false

        • © 2020 Twitter
        • About
        • Help Center
        • Terms
        • Privacy policy
        • Imprint
        • Cookies
        • Ads info