Adapting WozMon for the breadboard 6502

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Adrien Friggeri, Aleksey Smolenchuk, An Dương, Anthony Weems, anula, Ben, Ben Cochran, Ben Williams, Bill Cooksey, Bill Watkins, Binh Tran, Богдан Федоров, Bradley Stach, Brian Haug, Burt Humburg, Carl Fooks, Carsten Schwender, Chai, Chaitanya Bhatt, Chris Anders, Chris Lajoie, Chris Sachs, criis, Cristi Cobzarenco, Daniel Pink, Daniel Tang, Daniel Zimmer, Dave Walter, David Clark, David Cox, David Dawkins, David House, David Klassen, David Sastre Medina, David Turner, Dean Bevan, Dean Winger, Deep Kalra, Dennis Henderson, Dennis Schubert, Dilip Gowda, Dirk Sperling, Dmitry Guyvoronsky, Dustin Campbell, Dzevad Trumic, Emilio Mendoza, Eric Dynowski, Erik Broeders, Erik Granlund, Ethan Sifferman, Eugene Bulkin, Evan Serrano, Evan Thayer, Eveli László, EvinSaysMarxWasRight!, Florian Bürgi, fxshlein, George Miroshnykov, ghostdunk, Gregory Burns, GusGold, Hailey, Hovis Biddle, Ingo Eble, Jacob Ford, James Beldock, James Capuder, Jared Dziedzic, Jason Bowen, Jason DeStefano, Jason Grim, Jason Thorpe, JavaXP, Jaxon Ketterman, jemmons, Jeremy Cole, Jesse Miller, Jim Kelly, Jim Knowler, Joe Beda, Joe Pregracke, Joe Rork, Joel, Joey Murphy, John Hamberger jn., John Henning, John Meade, Jon Dugan, Jonn Miller, Joseph Portaro, Josh Smith, Justin Graziani, Kai Wells, Kefen, Ken Paul, Kennard Smith, Kenneth Christensen, Kyle Kellogg, Lambda GPU Workstations, László Bácsi, Lithou, Lukasz Pacholik, Marcos Fujisawa, Marcus Classon, Mariano Uvalle, Mark Day, Martin Noble, Mats Fredriksson, Matthew Clifford, melvin2001, Michael, Michael Cartwright, MICHAEL SLASS, Michael Tedder, Michael Timbrook, Michael Weitman, Miguel Ríos, mikebad, Miles Macchiaroli, Muqeet Mujahid, Nate Welch, Nicholas Counts, Nicholas Moresco, Nick Chapman, Olivier HUBER, Örn Arnarson, Paul Heller, Paul Pluzhnikov, Phil Dennis, Philip Hofstetter, ProgrammerDor, Ralph Irons, Randal Masutani, Randy True, raoulvp, real_huitz, ReJ aka Renaldas Zioma, Ric King, Richard Wagoner, Rick Hennigan, Rob Bruno, Robert Brown, Robert Diaz, Robert Keown, Robey Pointer, Roland Munsil, Sagnik Bhattacharya, Sam Sturgis, Scott Gorlick, Scott Holmes, Sean Bright, Sean Patrick O’Brien, Sergey Kruk, Shane Mulcahy, SonOfSofaman, sorek.uk, Spencer Ruport, Stefan Nesinger, Stephen Kovalcik, Stephen Riley, Steve Jones, TheWebMachine, Thomas Eriksen, Tim Oriol, Tim Sanders, Tim Walkowski, Tom, Tom Smith, Tyler Latham, Usseod, Vincent Bernat, Warren Miller, Wim Coekaerts, Wraithan McCarroll, Yee Lam Wan

[@rager1969]

Ben's big brain modifying the big brain work of Woz is lovely to watch.

[@markrix]

That ascii chart has to be one of the most viewed images on the internet IMO

[@blakelee4555]

Well I know what I'm thankful for this thanksgiving

[@zekodun]

Ben is not helping my addiction to old 6502 and 6800 systems. Not kidding, since the late 90's I've been wanting to build my own trs 80 MC-10 and c128 but never could grok electrical engineering enough as a kid to do. Watching these vids just show it is something that even a software guy like myself could do and even inspiring one to take on building a MicroVAX.

[@joeblow229]

It's so neat that you're still working with these breadboard computers! I remember back in 2019 I found one of your videos, and it inspired me to build a Z80 based desk light with LEDs and a "resistor ROM". It's still running four years later :)

[@audacious1876]

Wonderful 🎉

[@blazernitrox6329]

WozMon is such an incredible piece of software. Truly , Woz was one of the developers of all time.

[@KingJellyfishII]

WozMon is such a piece of software. Truly , Woz was one of the developers of all time. FTFY

[@erikb3799]

WozMon is a piece of software. Truly, Woz waz a developer from time. FTFY

[@rm_steele]

@@erikb3799 WozMon is software. Woz was a developer with time. FTFY

[@sakura_x64]

@@rm_steeleWozMon time! FTFY

[@PeranMe]

At LEAST one. Developers.

[@13mudit]

Perhaps subconsciously, I knew this video was going to be released today. I had just completed my 4th rewatch of the entire 6502 series yesterday. Thank you Ben

[@theorixlux2605]

I am technically up to date on all episodes. I am practically still on episode 1. I am officially on my 7th rewatch of the series so far. So... Me, as a vet, says; Woah, Wozman left us two bites? That rascal! I hope it fills me up like them Webb Sight cookies!

[@RussellBeattie]

That serial UART bug is a such a pain! Having to loop and wait is such a waste when the chip could just do the right thing.

[@oneeyestudios]

Today has just become a happier Thanksgiving. Thanks Ben.

[@tomedmonson501]

Thanks, Ben, you are an incredible communicator. I haven’t done any assembly language since the late 1980s, but I could follow along with you just fine. I’m looking forward to watching a lot of your other videos.

[@sirflimflam]

Hey Ben, I just wanted to say I've been following your videos for a long time now and you are probably the only person who has managed to really explain how all this low level stuff works in a way that I get. The breadboard 6502 is seriously one of my favorite series. Keep doing what you do. Cheers

[@StevenHokins]

Awesome video, thank you for this Woz series ❤

[@AndersNielsenAA]

Still amazing how Ben makes it look so easy to teach these things :)

[@ItsJustNeto]

It's always a good day when Mr. Ben publishes a video 😀

[@vdubjunkie]

It’s one thing to figure all this out and yet another to do such a fantastic jovv explaining it all so anybody with the interest can follow along. Thanks again for putting in the time!

[@cryptic_daemon_]

U know its a thankfull day, when the bob ross of computer engineering drops another banger!!

[@sudo4598]

@@pikadroo you are seriously implying that he's doing this to sell products?

[@TheDanEfranChannel]

@@pikadroo”Ross used his television show to promote a line of art supplies and class recordings, building what would become a $15-million business” -Wikipedia

[@kaitlyn__L]

@@pikadroohe literally tells you how and where to buy his special paint brush set in every episode, and each episode assumes that to follow-along you have all the tools in the exact sizing and quantity (especially the small/medium/large spatula scraper things, which came in all sorts of sizes).

[@ecosta]

Amazing how many features Woz packed in 254 bytes. Decades later, a "Hello World" fetches 300MB from 3k dependencies.

[@DirkJMartens]

What a great series this is. So much fun. So educational. So entertaining. So meaningful. Two comments: 1) I think at least 2 steps should be added in the RESET section of the code: a) initialising the stack (LDA #$FF and TXS) and b) initialising the ACIA (LDA #$00 and STA ACIA_STATUS) Both were there in previous videos. Relying on the hardware reset of the CPU/ACIA to achieve this is (I think) much more risky than relying on the wraparound from $FF to $00 after an INC and the other tricks that the Woz used to save a few bytes here and there. 2) Adding the two initialisation steps and still fit in the 250 bytes requires to free up some bytes somewhere and I was thinking to initialise the ACIA with "receiver echo mode on" (i.e. set bit 4 in ACIA_CMD) so a character will automatically echo on the terminal and we don't need to do it via code.

[@hamzawali2893]

The legend is back!!!!

[@aimah4390]

Thank you for sharing this information

[@NickFrom1228]

Man this brings back memories. Thank you for the walk through the past.

[@kaitlyn__L]

Always love how you explain assembly.

[@DaveVW]

Thanks! you gave me the confidence to port WozMon to my own 6502 minimal emulator, then to Commodore Vic-20, 64, 128 just for fun.

[@cobbrobotics]

Cool video, excellent explanations and inspirational. Thank you!

[@lightdark00]

A Thanksgiving miracle that you showed back up! Happy Thanksgiving!

[@Controllerhead]

EDIT: Apparently the 65C02 DOES have INC / DEC for A which the original 6502 does not, disregard the following comment, i'll keep it as is, but still worth pointing out it won't work on a 6502. 7:48 You can't DECrement A... bruh... that is not a valid instruction on the 6502 =( ...If your display isn't working (which i notice you didn't show) this probably explains why... that delay loop isn't doing what you think it's doing. god knows what that built as... Just use X / Y with DEX / DEY and that should fix it. Otherwise i always appreciate your content!

[@maixicek]

thank you Ben for this video 🧡

[@danieljudah8992]

What an unexpected content on Thanksgiving! Thank you!

[@plato4ek]

At last! I've been waiting for your next video so long! And here it is! 🥳

[@Scriabinfan593]

Was not expecting a video from on you on thanksgiving day. Happy thanksgiving and thanks for the video. I'm sure i'll learn a lot from this.

[@michaelkaercher]

as always a pleasure to watch

[@Tsanislav]

Great video. Thank you!

[@Sommyie]

The ending is the chef's kiss. ❤

[@CraftMine1000]

Always when I see a new Ben eater video I get happy :)

[@dacomputernerd4096]

Oh new video! Can't wait to watch it

[@IslandHermit]

Convenient that the code above SETBLOCK leaves 0 in the A register so the extra shift won't cause any problems.

[@LivingInLowLevel]

Good job 👍

[@willofirony]

Masterclass

[@bigkeoni6429]

I'll be gifting my self for Christmas with the se kits, along with the video card.......great stuff Ben

[@truckjumperdude]

What a better thanksgiving this is

[@der.Schtefan]

Your videos are what half the Internet is waiting for :)

[@killhim4400]

The legend has returned

[@BytebroUK]

You make such good vids. Probably going to have to do the Patreon thing at some point soon.

[@uni-byte]

Very nice!

[@Otakunopodcast]

Funny, I was just experimenting today with porting WozMon to the Commodore 64. Yeah, I know, kind of pointless, since there are dozens of other, more capable ML monitors available for the C64. But it was kinda fun, and also helped me in my continuing efforts to learn how to program the 6502 and how to use the Turbo Macro Pro assembler. (Also I was bored and needed something to do :) ) Had to put together some kinda hacky, very much not Woz-like code to interface with the C64 (cursor handling is... not fun) but I was able to get the thing to work! :)

[@toby9999]

I created my own ML monitor for the C64 way back in the 80s. All I could get then was a cartridge based version, and it wasn't very good.

[@saltyhashes1781]

Wow! Who would have guessed! Machine Learning in the 80s!

[@DigitLineEletronica]

Fantastic...

[@franciscovarela7127]

Nice work.

[@noureddinebenakrim5458]

The hero is back

[@Devmedow]

Very awesome

[@sean_vikoren]

pure gold

[@CamdenDaley-cb6ek]

Babe wake up new Ben Eater video.

[@Dirty_Bits]

There are only a couple things that I'll drop everything for - Ben Eater vids make that list!

[@wanderingmoon9772]

Id love to see more breadboard projects showing how to program Ic/microcontrollers. I would also love to see you discuss more about data sheets. I have a reclaimed motor from a vacuum I'm having a hard time finding a datasheet for.

[@LiamDennehy]

It would be interesting to see you assemble a program then load that into RAM over the serial port using the monitor, skipping the while ROM flash process.

[@tim_allen_jr]

So cool

[@rachelf6745]

babe wake up new ben eater just dropped

[@Devmedow]

I happened to bring out my breadboard computer today and then found this was just uploaded.

[@Marenthyu]

... and now it's 3am again.

[@larsmller2253]

Hi Ben Thanks a lot for your amazing videos. You are a wonderful explainer, that makes it easy to follow. I have a question about the speed of your 6502 computer. The W65C02 can run up to 14Mhz, but I remember you talked about timing for the chip selections. I want to run it at 10Mhz, what would mean that I need to chance/improve to make this possible ? 🙏 Best Regards Lars

[@user-rb4op3je2p]

How to be as great as you are, Incradebal

[@justovision]

Great work. As you go through changing the ascii values it's worth noting I think that you're just subtracting 8 from the significant byte. 8 -> 0, A -> 2, B -> 3... good reminder that hex is just numbers. Thank you for doing these videos.

[@marred2277]

subtracting 8 from the significant nybble I think, more accurately, or 128 from the byte, cheers

[@deltakid0]

I would really love to get back to 74 series and built may be a hardware multiplier

[@CZghost]

Is this a reupload? I remember watching a very similar video of yours if not the same earilier.

[@VGCCCCC]

One thing idea Ive had is since the original WozMon program was for a keyboard and a screen, could you adapt it to use your keyboard interface and vga card?

[@kaitlyn__L]

The Apple I’s screen driver circuitry was basically a serial terminal in a trenchcoat, which is part of why it worked so well for a UART with only a few mods. It could definitely be done, but would require essentially implementing all the ASCII-to-character stuff which this code just assumes magically happens.

[@ed_halley]

I would just add one thing. Woz's code needed deep analysis to find tricks like the Y high bit at NOTCR. Comment *why* you're using Y high bit in the code. Of course other comments in the same vein would help too. Source code is for humans, not just computers.

[@DeeBash]

Hi Ben, it would be so good when you teach us Paged and Segmented memory.

[@bobweiram6321]

Ben the Eater didn't eat turkey so we can learn 6502. We should all be grateful.

[@Beerkeg92]

Perhaps in a few years we'll get doom running on this thing...

[@AftercastGames]

Couldn’t help noticing, but does adding the shift left at the end of the video break the code above it? Probably need to verify. Great video. Gives me some ideas for making a cross platform version.

[@marred2277]

no, the accumulator will contain 0 at the end of that routine, so the ASL's will do nothing

[@JSRFFD2]

I don't remember exactly how the ACIA circuitry worked, but I wonder if a hardware hack to the ACIA output could have pulled bit 7 high when it outputs on the bus, thus not needing so many code changes. It means you could never read a serial byte with bit 7 high, but would be more compatible with other Apple 1 software.

[@truezulu]

Arh... I wouldn't say you did a video recently... That's not quite accurate...

[@JEMSS97]

Hello, can you do video about the circuit inside an op-amp and how it works. Thanks!

[@herauthon]

i saved this Video for the future.. so..mankind will interconnect again.. at lo-power.. it be called the BEE - the Ben Eater Experience. :D

[@anon_y_mousse]

Are you going to implement a C compiler for the breadboard computer or can you use cc65 for it?

[@clementpoon120]

i wonder if we can make a platform independent version of wozmon that can run on practically everythign

[@marred2277]

I would say no, this is low level, you can't really get any closer to the hardware, so it necessarily is very closely tied to the hardware it's running on.

[@uzbekistanplaystaion4BIOScrek]

a portable version of wozmon in assembly is basically impossible, because there are many different versions of assembly that correspond to different instruction set architectures, which can vary significantly. you could write a program in c that implements the features of wozmon, which could be compiled for most (if not all) architectures, although it'd inevitably be less compact and maybe less performant.

[@SergeAx]

Hi, Ben! Am a big fan of your channel. Thank you for your work! I have a question: why don't you put all ASCII codes to constants in the beginning of the file, use those constants through the code, and then just change them in one place? Given educational spirit of your video, that would be a good lesson of making code more readable and easier to refactor!

[@DirkJMartens]

I had the same thought, and defined the constants and replaced e.g. all "CMP #$1B" with "CMP #ESC" ... but when trying to analyse the code, understanding the result of "CMP #$1B" when the A register contains e.g. "$30" is much easier then "CMP #ESC" ... so I ended up editing the code again and adding the ASCII codes in the comments: "CMP #ESC ; ESC = $1B" On the other hand, it does make perfect to replace e.g. "LDA #$5C" with "LDA #PROMPT" and define "PROMPT = $5C" so you can change your prompt to ">" or "*" easily if you like.

[@4115steve]

this would be cool to see as a "little man computer"

[@SFS_Paraverse_Studio]

From what website do you buy the chips like the counter, the adder etc...?

[@davidadesina3321]

Yo I've got a question If hyper v is bare metal then I should be able to boot straight to say Kali right? If that's true can you show how

[@gebanb]

Will you use the video card that you built earlier?

[@iDoComputers]

3 hrs ago!! and today’s thanksgiving???????

[@carsoncoder]

You shoukd try to run C code on the 6502.

[@th3darkgem566]

I wonder, is there some app or something to simulate this sort of thing, or just program it on my pc?

[@YourMultiversalShowerShitter]

Hey were did the video card go?

[@roysainsbury4556]

This was interesting. I decided to try converting it to Z80 (on a TRS80 emulator), and it seems to work as intended (of course, the TRS80 has a much better disk based monitor, but it was just an experiment). Interestingly though, I notice a lone "DEC" instruction in the ECHO routine. As far as I know, the 6502 has no instructions to increment or decrement A. X would do just as well I guess. Perhaps DEC is one of those illegal instructions, or maybe a modern equivalent 6502 actually implemented these? I tried DEC (and DEC A) on an online assembler, and it didn't accept it.

[@sloomeamohammad8899]

I am an Arab, I love your videos and I watch with subtitles, thank you ❤

[@guilhermeperotta3092]

Hey Ben, you need to update your Chrome browser :D

[@halfsourlizard9319]

Why can't all of KZbin be people editing interesting code in Vim.

[@jortand]

I’m not even American but I’m pretty thankful for this

[@Squossifrage]

04:08 Why not change CR to LF while you're at it?

[@futileskills]

Congrats, chatgpt sent me here. You are even famous with AI lol

[@SerjLevonyuk]

Please make "Worlds worst ethernet adapter". DIY scheme on breadboard that can recive an ethernet frame and send it to pc over serial.

[@am2dan]

Who else was trying to recall all those ASCII codes before he could look them up?

[@ROBOTRIX_eu]

[@tobiasthrien1]

1:17 You can simplify your life by adding: set vartabs=16,8,15 set expandtab to your vimrc. Then you don't need to enter every space individually. Instead you press Tab onces and vim will enter the appropriate number of spaces for you. Similarly at 2:06 if you use "R" (Replace) the comment will stay where it is.

[@user-ru1ol2hb1k]

我也为我的6502计算机适配了WozMon，只需要改动少量代码就可以了。

[@RegisMichelLeclerc]

Well, you could have seen that the codes you were yesting were ASCII + 0x80h, so you just needed to syvstract 0x80h from the test values as well. Now all those tests take a lot of space, another way of seeing it is to make a table of pointers to subroutines (way to speak, it's just JMPs, not necessarily JSRs), but that would change completely the "spirit" of the code. However, I don't know if the 6502 is able to do JMP [address] with the jump address stored there, like on the 8086?

[@user-ox2su6kh8w]

www.youtube.com/@SebastianLague/featured

[@spageen]

I'm pretty sure Steve Wozniak was Jimmy Neutron as a kid