It's a tricky business. Essentially an NMI is a "ninja function" that can call itself even if your program doesn't. So it needs to leave everything the way it found it when it's finished.
I would love a quick tutorial along these lines in which you just show a sprite moving from left to right on the screen. I was able to make the "HELLO" scroll across the screen by updating your example in GitHub, but I know there is a better way to do it.
I love how starkly different the 6502 is from modern x86_64. It really shows how far we've come, going from no hardware multiplication to something like VFNMSUB132PD (Fused Negative Multiply-Subtract of Packed Double Precision Floating-Point Values). I don't even know if that instruction has ever been used for any meaningful purposes, but it's there.
i just did a bit of research into the cpu extensions that use the set of instructions that comes from, and it doesn't surprise me at all that its a SIMD instruction. ive recently been learning SIMD for fun and its honestly pretty awesome stuff
looking into what exactly this instruction does, its actually surprisingly simple. its basically just doing "x = -(x * y) - z" over a set of data provided to it (SIMD stands for "Single Instruction, Multiple Data"). so it actually likely has a lot of practical use
When I was in school I couldn't *get* math or computer science stuff until I figured out a way to visualize, or *feel*, it in my head. So my hope with the channel is that I can help others do the same with the graphics and explanations.
@@NesHacker Omg, me too, the school methodology: "throw a bunch of numbers; ask students to figure out". I began to understand math better when i began to mess with graphical calcs...
Man, never thought ill watch a 9min vid about PI in the NES, but how you explain it and how you put it graphically makes it very engaging. Thanks for this video even though i dont have any idea of it!
I will share this all the places on Pi day. I am no one, so I don’t see how it will matter much, but this video is deserving of some serious Pi Day views, so I will do my part
I considered it, but I kinda thought it best to keep the release schedule consistent... otherwise it would have been a nearly a month and a half between releases :)
I'm Brazilian and I study computer engineering, your videos inspired me a lot and I'm more and more interested in programming with the 6502. I would love to learn more about NMIs and I'm already following your playlist on basic assembly!
It's not entirely true that the nes lacks multiplication and division, but that it's limited. There are 4 bitwise opcodes, ROL, ROR, ASL, and LSR which you can use to shift the bits left and right which can be used to multiply and divide bytes by 2.
A complex, daunting process explained in a very understandable and concise manner. The visuals are very smooth and helpful and your speech has a nice, relaxing cadence. Exceptional video, can't wait for more.
@@NesHacker One of the first things I wanted to do as far as NES coding projects were concerned was to "simply" count frames since poweron so I could get an accurate idea of how my video capture device interacted with the console(s). Which means having to deal with enough PPU stuff to be able to set tiles on the screen, and enough math stuff to be able to increment and display, at bare minimum, a 16 bit integer. I figure there's enough I can glean from your code to muddle through it.... now all I need to do is find the time...
This was a really great video, very well explained. I’d love it if you could go into more depth on handling interrupts, I had no clue you could save the address of a register on an interior call. Could also do a brief tutorial on NES audio programming, it’s one of the more difficult concepts I’m trying to grasp.
Wow, I was once assigned to do this using the 8086 assembly and didn't even try, was too hard back then but definitely knowing that algorithm would have changed a lot
I have a video request: a video covering the ins and outs of scrolling on the NES. From what I understand, you need to go through all sorts of hoops to be able to get scrolling in all directions. I've studied enough of the hardware to understand it can do general scrolling in one direction, but beyond that is a mystery to me. What makes bi-directional scrolling so hard, how is it accomplished, and what are the limitations to it depending on the mapper you're using? NESMaker is a good example of how this frustrated me a lot in the past. They released this tool allowing you to build your own NES games without needing programming, but anytime they were asked why can't they provide four-way scrolling, they pretty much just said it's not possible and those of us not in the know were left just wonder "But why?" I'd LOVE to see you cover this, and Vdubs also suggested teaching more about "NMIs and graphics programming." I think a video on scrolling and all the hurdles would be a great start.
It's definitely on my list. 4-way scrolling *is* possible, I mean look at Super Mario Bros. 3... So I kinda wonder what's going on with NESMaker where they can't support it...
@@NesHacker Yep, not to mention all those RPGs! I'm almost certain I remember the main dev of NESMaker mentioning they sort of limited themselves due to the mapper they chose, but I think I've even seen a plain NROM demo with 4-way scrolling, so I'm still confused.
@@NesHacker actually 4-way scrolling *isn't* possible. iIRC there's an RGMechEx video on how smb3 cheats but the gist is that there's a load of sprites on the left side of the screen to mask the fact that the tiles wrap around (and you can see colour glitches on the right hand side of the screen because of how NES colour mapping works) The NES has two scrolling modes: 2 screens vertically, and duplicated horizontally; or 2 screens horizontally, and duplicated vertically and SMB3 cheats by covering the left side of the wrapped tile
4 way scrolling is possible, whether by including extra RAM on the cartridge for 2 more nametables, or "cheating" like in Super Mario Bros 3 and a ton of other games
A very cool video. You may not have planned this but I got a chuckle out of the NES "speaking" in Japanese as the NES was not released in Japan, the Famicom was.
It's so cool to me there's a way to compute pi without floating point math... and digit-by-digit like that... what a cool algorithm. Math is so freakin' cool sometimes.
Loved the video! Quick code note, when an interrupt is fired, the 6502 will push the current PC to the stack, and then will also push the current processor flags as well. This is why you use RTI as it pops both the processor flags and the PC. So anyway, all I'm trying to say is you don't need to do php/plp when an interrupt is fired since that is done for you.
@@NesHacker awesome! Sorry for that then, I tried reading the comments to see if someone else caught this but I didn't find one. Anyway, thanks for responding, can't wait to see the next upload!
For some reason I assumed this would be about using a Raspberry Pi with a NES, like what suckerpinch did a few years back to implement custom video via MMC/PPU shenanigans.
This makes sense considering 6502 is a general purpose CPU. Chances are there are limitless options to expand this chip by retrofitting current code so it can understand it for low watt, unattended processing.💯
@@jefftheworld it was on Google play actually, I remember I didn't have a credit card or any way to buy stuff online so I just searched for all the free music I could find!
Nitpick: You talked about floating point with a graphic of stock quotes ... Due to rounding errors, using floating point for currency or stock shares is bad bad bad! You would need to use an integer math representing cents or even fractional cents.
Amazing video! Visuals were amazing, and the breakdown of compilicated math algorithims made it easy to understand. Also cool because you pushed the limits of the NES!
Very nice, personally I would have used my own algorithm that would have been super imprecise and slow. But aside from using a fast algorithm, you did a great job!
The Ricoh 2A03 and Ricoh 2A07 (those were the CPUs in the NES) are just 8 Bit CPUs with MOS 6502 instruction set running at 1.79 MHz. Oh boy, those CPUs used a technology node of 6 μm, today CPUs are below 6 nm (that's a factor of 1000 smaller). And the 6502 was just a stripped down version of the Motorola 6800 and it's the CPU also used in the Atari 2600, Apple II, Commodore 64, or BBC Micro, so of course it is capable of doing way more than running console games. It is a general purpose CPU even though a pretty limited one by today's standards.
nice vid , I always try to stay away from floats and these type of stuff with 6502 since its always harder than on modern day processors . also not sure if you know this but you dont have to backup the Proccesor flags at the start of an interrupt , thats done automaticly . Otherwise RTI would be exactly the same as RTS
I thought it might be the case that the interrupt handler auto stored the status register, but I was like five days into deep hacking on the game, very tired, and figured a couple extra cycles wouldn't matter so I could be "safe" and just throw stack push and pop in there. Fully computing all 960 digits takes quite a while even on the highest speed settings I could get on Mesen, and even minor issues were causing all sorts of havoc with the final digit results. So I was definitely being over cautious when handling the rendering here, haha.
You use the stack to store the values of the registers during an NMI interrupt, but isn't it better to store them into the zeropage ? It would use less clock cycle.
fixed point arithmetic would've also been an option, as it's functionally the same as floats but a lot easier on the hardware (and easier to implement). a lot of NES games actually use fixed point math to keep track of characters/enemies and their speed/acceleration and such! and honestly it did hurt my pride a bit that you didn't consider it because i made a fixed point library for cc65 (a 6502 C Compiler designed for these systems) for exactly these kinds of projects. :(
Oh, sorry about that, no offense intended at all! I don't know why but I had it in my mind that there just *had* to be a way to compute the digits using only integer math, so when I found the spigot algorithm I kinda just went with that :)
@@proxy1035 Right on, and honestly this is all bound to come up in a future video, so I'll definitely give your library a spin when I get to covering the topic again :)
can anyone pls explain to me why I end up watching this type of videos with so much interest from start to finish without understanding a thing of what is explained in this video :))) btw, you have a great voice/narration
I wonder how many instructions do modern CPUs actually have, as in, what is the list of micro code instructions.can a modern CPU actually do square root in hardware? Or is that just a series of micro code instructions?
Modern processors like the Ryzen 9 have many, *many* instructions. They also have integrated FPUs, which implement instructions like "fsqrt" for handling floating point roots. That said, take this with a grain of salt. I am not an expert on modern processor architectures, so if someone else knows more or wants to expand/correct, by all means! :D
Honestly i would love to see the debugging process on nes, i have some problems with updating backgrounds and its like no one else had anything like that before, you should collect similar bugs and cover them
I wonder how much CPU went for rendering and how much for computing? Would be interesting to see video side by side where on one side your current code fills screen and on other side entire number is calculated first and then everything is printed once and with no animation.
This video was very intriguing even though I understood under 10% of it. What level of computing do you learn related with the video? The only thing I understand is the Pi and the first part, and though I know nothing of this field, this does seem awesome
could you do it in system ram if you just pushed a digit to the screen and reused the memory address or would that segfault / not render properly / still not enough ram for the code?
The spigot algorithm sure is interesting. I approached the problem of calculating pi a bit differently back in the day when I were in high school and were bored. I approximated pi by calculating the length of a very short triangle and then multiplied that by how much of a circle it represented. It used a loop that started with a 90 degree corner. Ie, point A at X=0 and Y = 1 and point B at X = 1 and Y = 0. Find the center point C between these two point. Draw a line from origin to C, extend until it is of length 1, this point is our new point A. Repeat this n times. Each time we get 2x closer to pi. Our approximation of pi equal the distance from A to B multiplied by (4*2^n)/2 We started with a rather lack luster approximation of 2.8284, kind of far off. The approximation is also always on the short side. Is it a great solution? Absolutely not, it is really slow and you have to do a massive multiplication in the end, and the distance between A and B has to be of slightly higher accuracy as the number of digits you want in the result. (and working with huge numbers is a very efficient way to be slow...) But it works and is simple enough to understand. Unlike a lot of more efficient and nuanced approaches that seem like magic in comparison.
Awesome, I've been meaning to do some non x86/non-desktop programming at some point, console is not a checkbox I've ticked yet, though I'm not quite sure I want to dive into assembly just yet, I'm working my way backwards. Though I guess the benefit of something like this is that its more pure, you won't have to disentangle some proprietary API such as what an xbox might have. Historically c wasn't used because it was slower? Is this still the case, how is c programming for something like the NES nowadays? Is inline assembly a good way to have the best of both?
You can do NES programming in C or Assembly, choice is yours. But some of the rendering stuff and advanced techniques requires precise cycle timing, so you have to break down into assembly to do that. I mostly teach assembly on the channel cause I think it's fun and a more natural way to program NES games.
quick question about the algorithm, if you need to store what base each digit is in, what makes the algorithm better than just storing all the digits in base 10? or is this just a proof of concept that the nes can indeed calculate the digits of pi 'by hand'?
I had a thought when watching this video - If an NES is not equipped with logic to do something, a library can just be designed to do it? For instance, the SNES has something called mode 7, and this is a hardware feature that developers can call upon. For machines that don't have this hardware, like the Sega Genesis, can a library be designed to achieve it?
Indeed, but... At 1920 digits I'd need 2 × 1920 × 10 / 3 = 12,800 bytes for the array, which is 12.5 KB. With that number I'd need to use something like the MMC5 to fit the data into contiguous memory (I think you can map WRAM on an MMC5 board into $8000+ range, though I've never done it). Also it would take *much much* longer to compute, haha.
I tried implementing something like this on the GBA. It almost worked, but some of the digits are wrong since the algorithm outputs "10" as a digit sometimes. What did you do to fix this?
Great to see coders using assembler and struggling with little RAM. Back in the late 70s I did the same and resorted to using the video memory directly as storage. It’s been a while, but we have come a long way since 4k was total RAM.
Working in a more limited environment can be really fun because you often have to get creative. I didn't exist in the 70s, but I probably would have had a blast programming back then :)
Computing the Fibonacci sequence is kinda trivial compared to this. Even though it's inherently recursive, there's a *very* fast dynamic programming solution that requires storing only three variables.
I haven't programmed 6502 assembly since the 90s on my C64, good memories. I had to do it on all on paper then poke all the bytes into memory with some C64 basic via the programmers ref guide, then call it with SYS xxxxxx. Hah, all that to make the text wiggle about on the screen or change char sets, make sprites. Fond memories.
hmm you could have a NesPi NesPi. any rom you make for the NES would run on the NesPi emulator (a raspberry pi running emulation station). double Nes Pi?
Happy Pi day, everyone 😄
It got recommended to me on the right day. Happy Pi Day!
Piepi
mmmm pie
And here it is again 😊
Hey man, can you please explain the spigot algorithm breefly
I remember when I realized that game console were just special-built computers and not just "magic game machines" - so cool
I chose to become a software engineer as a kid the minute that realization hit me.
@@NesHacker Same here.
Here in the UK many of us started with a microcomputer instead of a games console, which was kinda cool, but I really wanted to play sonic.
Computers without keyboards )))
@@syrus3k Acorn BBC micro?
I would love to learn more about NMIs and graphics programming.
Got it, I'll start tooling around more with some ideas on the subject!
It's a tricky business. Essentially an NMI is a "ninja function" that can call itself even if your program doesn't. So it needs to leave everything the way it found it when it's finished.
@@williamdrum9899 No kidding. I've played around with it a little bit and oh boy the things that can go wrong if you don't use the stack
@@NesHacker ❤طططططج❤❤❤❤❤❤❤❤❤❤❤❤ض رب في ص🎉
😮 😢
I would love a quick tutorial along these lines in which you just show a sprite moving from left to right on the screen.
I was able to make the "HELLO" scroll across the screen by updating your example in GitHub, but I know there is a better way to do it.
I love the fact that the NES is asking "What is 'Flop'?". Just a nice touch. Also, 1:00
NES translations
1:03 「あのー、フロップは何ですか？」= umm, what’s a flop?
5:00 「そうです」= that’s right
素晴らしい、私も日本語が学んでいます。
its kinda strange seeing google translate the other side to be the exact same as eachother
NES hit him with the "Et'oo" and the "Sodeska?"
It would talk like an anime.
Super cool! Loved, "do you even flop bro"
So, when that joke came to me, I was like 10 hours deep doing graphics work. I was so tired I basically fell apart laughing and had to animate it in 🤣
I love how starkly different the 6502 is from modern x86_64. It really shows how far we've come, going from no hardware multiplication to something like VFNMSUB132PD (Fused Negative Multiply-Subtract of Packed Double Precision Floating-Point Values). I don't even know if that instruction has ever been used for any meaningful purposes, but it's there.
It’s probably just for compilers to use.
😃 yay! 🎉🎉🎉🎉
i just did a bit of research into the cpu extensions that use the set of instructions that comes from, and it doesn't surprise me at all that its a SIMD instruction. ive recently been learning SIMD for fun and its honestly pretty awesome stuff
looking into what exactly this instruction does, its actually surprisingly simple. its basically just doing "x = -(x * y) - z" over a set of data provided to it (SIMD stands for "Single Instruction, Multiple Data"). so it actually likely has a lot of practical use
Great video. The use of visuals on this channel to explain assembly and binary operations are very helpful.
When I was in school I couldn't *get* math or computer science stuff until I figured out a way to visualize, or *feel*, it in my head. So my hope with the channel is that I can help others do the same with the graphics and explanations.
@@NesHacker Omg, me too, the school methodology: "throw a bunch of numbers; ask students to figure out".
I began to understand math better when i began to mess with graphical calcs...
Man, never thought ill watch a 9min vid about PI in the NES, but how you explain it and how you put it graphically makes it very engaging. Thanks for this video even though i dont have any idea of it!
Well, I am glad you enjoyed it, haha
@@NesHacker yes, i did enjoy it
This video is going to blow up on Pi Day. 🥧
He should have released it on Pi day.
I will share this all the places on Pi day. I am no one, so I don’t see how it will matter much, but this video is deserving of some serious Pi Day views, so I will do my part
I considered it, but I kinda thought it best to keep the release schedule consistent... otherwise it would have been a nearly a month and a half between releases :)
@@NesHacker Pi day is coming up in a couple of days.
No it won't. Video was uploaded too early. I agree with Kermit.
I sold my stack of Megaman NES carts around 8 years ago... You just hit me so hard in the feels with your stack.
This video deserves 1000x the views it currently has. Thank you sir. This was Great!
That's a lot of views 😆
I'm Brazilian and I study computer engineering, your videos inspired me a lot and I'm more and more interested in programming with the 6502. I would love to learn more about NMIs and I'm already following your playlist on basic assembly!
It's not entirely true that the nes lacks multiplication and division, but that it's limited. There are 4 bitwise opcodes, ROL, ROR, ASL, and LSR which you can use to shift the bits left and right which can be used to multiply and divide bytes by 2.
Indeed, I more meant "general arithmetic multiplication and division" such as a "mul" or "div" operation.
A complex, daunting process explained in a very understandable and concise manner. The visuals are very smooth and helpful and your speech has a nice, relaxing cadence. Exceptional video, can't wait for more.
Thanks! I am glad you liked it :)
Now I know, why a friend of my yesterday said he wants to make a NES-Pi calculator. He probably saw this video.
This is great stuff! Finally! A concrete, complete, and not too complex example of how to get an NES to do some actual work!
I'm glad you like it :)
@@NesHacker One of the first things I wanted to do as far as NES coding projects were concerned was to "simply" count frames since poweron so I could get an accurate idea of how my video capture device interacted with the console(s).
Which means having to deal with enough PPU stuff to be able to set tiles on the screen, and enough math stuff to be able to increment and display, at bare minimum, a 16 bit integer.
I figure there's enough I can glean from your code to muddle through it.... now all I need to do is find the time...
I mean, you *could* trade stocks on a Famicom ;)
ua-cam.com/video/Q9gbIZY1WY4/v-deo.html
This was a really great video, very well explained. I’d love it if you could go into more depth on handling interrupts, I had no clue you could save the address of a register on an interior call. Could also do a brief tutorial on NES audio programming, it’s one of the more difficult concepts I’m trying to grasp.
APU programming is a big one to tackle. As soon as I have a good way to explain it all and have done more research I'll be sure to cover it!
@@NesHacker thanks! I really appreciate that.
Wow, I was once assigned to do this using the 8086 assembly and didn't even try, was too hard back then but definitely knowing that algorithm would have changed a lot
As a Pi loving mathematician who has written many forms of the Spigot algorithm, bounded and unbounded, for various numbers... Well.. I'm jealous.
You have no idea how happy I am to hear that a mathematician is jealous of my work 😂
I have a video request: a video covering the ins and outs of scrolling on the NES.
From what I understand, you need to go through all sorts of hoops to be able to get scrolling in all directions. I've studied enough of the hardware to understand it can do general scrolling in one direction, but beyond that is a mystery to me.
What makes bi-directional scrolling so hard, how is it accomplished, and what are the limitations to it depending on the mapper you're using?
NESMaker is a good example of how this frustrated me a lot in the past. They released this tool allowing you to build your own NES games without needing programming, but anytime they were asked why can't they provide four-way scrolling, they pretty much just said it's not possible and those of us not in the know were left just wonder "But why?"
I'd LOVE to see you cover this, and Vdubs also suggested teaching more about "NMIs and graphics programming." I think a video on scrolling and all the hurdles would be a great start.
It's definitely on my list. 4-way scrolling *is* possible, I mean look at Super Mario Bros. 3... So I kinda wonder what's going on with NESMaker where they can't support it...
@@NesHacker Yep, not to mention all those RPGs!
I'm almost certain I remember the main dev of NESMaker mentioning they sort of limited themselves due to the mapper they chose, but I think I've even seen a plain NROM demo with 4-way scrolling, so I'm still confused.
@@NesHacker actually 4-way scrolling *isn't* possible. iIRC there's an RGMechEx video on how smb3 cheats but the gist is that there's a load of sprites on the left side of the screen to mask the fact that the tiles wrap around (and you can see colour glitches on the right hand side of the screen because of how NES colour mapping works)
The NES has two scrolling modes: 2 screens vertically, and duplicated horizontally; or 2 screens horizontally, and duplicated vertically and SMB3 cheats by covering the left side of the wrapped tile
4 way scrolling is possible, whether by including extra RAM on the cartridge for 2 more nametables, or "cheating" like in Super Mario Bros 3 and a ton of other games
A very cool video. You may not have planned this but I got a chuckle out of the NES "speaking" in Japanese as the NES was not released in Japan, the Famicom was.
Everyone knows that the NES' true home is Japan and that its an expat, jeeeezeee ;)
ACKCHEWALLY
It's so cool to me there's a way to compute pi without floating point math... and digit-by-digit like that... what a cool algorithm. Math is so freakin' cool sometimes.
Yeah I was pretty stoked when I found the paper detailing the algorithm
Great vid, awesome production quality and a super interesting subject all explained very well!
Thanks :)
Hey, thanks to the inspiration of this video I got a 10/10 in my parallel computing project, for university! Appreciated!
Loved the video! Quick code note, when an interrupt is fired, the 6502 will push the current PC to the stack, and then will also push the current processor flags as well. This is why you use RTI as it pops both the processor flags and the PC. So anyway, all I'm trying to say is you don't need to do php/plp when an interrupt is fired since that is done for you.
Yep, another viewer pointed this out as well, my bad! Thanks for watching and letting me know :)
@@NesHacker awesome! Sorry for that then, I tried reading the comments to see if someone else caught this but I didn't find one. Anyway, thanks for responding, can't wait to see the next upload!
This is very cool! Hasnt watched everthing but its sounds cool!
Hopefully you like it when you get to watch it all :)
@@NesHacker That was AMAZING very cool! Keep the good work man
I've been living in Japan and learning assembly for the past 8 months now, but I was very surprised to see your NES speak in Japanese xD
I mean- of course it speaks Japanese... it's from Japan 🤔
For some reason I assumed this would be about using a Raspberry Pi with a NES, like what suckerpinch did a few years back to implement custom video via MMC/PPU shenanigans.
A youtuber called suckerpinch made an NES slideshow app.
This makes sense considering 6502 is a general purpose CPU.
Chances are there are limitless options to expand this chip by retrofitting current code so it can understand it for low watt, unattended processing.💯
Cool way to bring in mappers to the series!
Oh wow, pleasure seeing you here! I'm a senior in college and I've had your albums on my phone since middle school!
Thanks! I've been searching for a way to approach the subject more that is interesting without being just an info dump.
@@AndrewGlitchMasterBalaschak That's wild, what a small world.
Whereabouts did you find my music way back then?
@@jefftheworld it was on Google play actually, I remember I didn't have a credit card or any way to buy stuff online so I just searched for all the free music I could find!
good job man keep up the work and continue working on this!!
Nitpick: You talked about floating point with a graphic of stock quotes ... Due to rounding errors, using floating point for currency or stock shares is bad bad bad! You would need to use an integer math representing cents or even fractional cents.
That's true, and my bad. Mostly just needed some basic b-roll to fill in some space xD
「あのー
フロップは何ですか？」
*"EVERYBODY DO THE FLOP!"*
Haha
Amazing video! Visuals were amazing, and the breakdown of compilicated math algorithims made it easy to understand. Also cool because you pushed the limits of the NES!
Thanks! I'm glad you liked it, though I'd say I didn't push them too hard. You should see what some of the people in the demo scene do, haha
Why limits?
This is really cool. I'm loving your recent videos.
Thanks, I've been really happy with my recent ones too :)
I like the joke at 1:00 :) "What is the flop?" :)
Yeah I am not sure if it's technically correct Japanese, but it's what I remember from lessons... 😂
@@NesHacker it was good enough for Google Translate, I guess.
ah yes , my videogame from my childhood. Pi for the NES. i especially loved it's requel/remake "Super Pi" fore SNES
Imho Super Pi was derivative and overrated :P
@@NesHacker D:<
to waaaaaar
Pi 64 was a 3D classic
From the thumbnail I thought you were going to make a cart with a raspberry pi inside
Yeah a lot of people say that, I should totally do it now xD
Not gonna lie, I thought this video would be showing a raspberry pi built into an NES cartridge that had multiple games on it.
So glad i found this channel, invaluable
Epic! Did not know you could do so much stuff in the NMI
+1 for NMI!
Haha, alright, I'll make sure to bump up the priority!
1UP!
i wanna see this running on actual hardware just out of curiosity
Omg You have 3.14k subs rn!!
Mmmm, 31.4k I think, but yeah really close to getting 10*pi on pi day, haha
In our language the word "nespi" mean "don't sleep" 😀
That's a pretty accurate description of my life when I was editing the video :P
@@NesHacker 😀
How come your videos is so dope
Great video. Not at all what I was expecting when I saw “NES Pi” in the vid title, but was interested anyways.
Yes, I want to learn more about using interrupts to do graphics programming on the NES 🙂
I was literally going to say that I liked your T-shirt and then you you just gave me the link to buy it😊
Very nice, personally I would have used my own algorithm that would have been super imprecise and slow. But aside from using a fast algorithm, you did a great job!
you missed a big opportunity to name it PI-NES
I think it's more like I *dodged* that opportunity :P
@@NesHacker nah definitely missed XD
I would typically click on "like" but it is currently sitting at 314 and I just can't bring myself to break that perfection...
😂
The Ricoh 2A03 and Ricoh 2A07 (those were the CPUs in the NES) are just 8 Bit CPUs with MOS 6502 instruction set running at 1.79 MHz. Oh boy, those CPUs used a technology node of 6 μm, today CPUs are below 6 nm (that's a factor of 1000 smaller). And the 6502 was just a stripped down version of the Motorola 6800 and it's the CPU also used in the Atari 2600, Apple II, Commodore 64, or BBC Micro, so of course it is capable of doing way more than running console games. It is a general purpose CPU even though a pretty limited one by today's standards.
Well stated :)
nice vid , I always try to stay away from floats and these type of stuff with 6502 since its always harder than on modern day processors . also not sure if you know this but you dont have to backup the Proccesor flags at the start of an interrupt , thats done automaticly . Otherwise RTI would be exactly the same as RTS
I thought it might be the case that the interrupt handler auto stored the status register, but I was like five days into deep hacking on the game, very tired, and figured a couple extra cycles wouldn't matter so I could be "safe" and just throw stack push and pop in there.
Fully computing all 960 digits takes quite a while even on the highest speed settings I could get on Mesen, and even minor issues were causing all sorts of havoc with the final digit results. So I was definitely being over cautious when handling the rendering here, haha.
Checked the whole video… didn’t understand anything 🙈
Imagine how I felt making it ;)
@@NesHacker atleast you know what youre talking about :)
You use the stack to store the values of the registers during an NMI interrupt, but isn't it better to store them into the zeropage ?
It would use less clock cycle.
Yeah that would be more optimal, thankfully in this case it didn't matter much... But with more complex rendering routines it certainly would!
fixed point arithmetic would've also been an option, as it's functionally the same as floats but a lot easier on the hardware (and easier to implement).
a lot of NES games actually use fixed point math to keep track of characters/enemies and their speed/acceleration and such!
and honestly it did hurt my pride a bit that you didn't consider it because i made a fixed point library for cc65 (a 6502 C Compiler designed for these systems) for exactly these kinds of projects. :(
Oh, sorry about that, no offense intended at all! I don't know why but I had it in my mind that there just *had* to be a way to compute the digits using only integer math, so when I found the spigot algorithm I kinda just went with that :)
@@NesHacker no worries, important part is that you got something working at all!
@@proxy1035 Right on, and honestly this is all bound to come up in a future video, so I'll definitely give your library a spin when I get to covering the topic again :)
Excellent video!
One minor correction: for your Patreon credits, you listed it as "Feb 2022 Supporters" instead of 2023
Yeah my bad, appreciate it!
can anyone pls explain to me why I end up watching this type of videos with so much interest from start to finish without understanding a thing of what is explained in this video :)))
btw, you have a great voice/narration
As far as I’m aware, the famicom has two main functions: video game and horse betting
never actually thought of that, but technically true
Thank you Mario!... but our next decimal place is in another castle
I wonder how many instructions do modern CPUs actually have, as in, what is the list of micro code instructions.can a modern CPU actually do square root in hardware? Or is that just a series of micro code instructions?
Modern processors like the Ryzen 9 have many, *many* instructions. They also have integrated FPUs, which implement instructions like "fsqrt" for handling floating point roots.
That said, take this with a grain of salt. I am not an expert on modern processor architectures, so if someone else knows more or wants to expand/correct, by all means! :D
Honestly i would love to see the debugging process on nes, i have some problems with updating backgrounds and its like no one else had anything like that before, you should collect similar bugs and cover them
happy 3.14 - i did run this on the everdrive. the screen was slightly cut off, but tons of fun !!
Really quality video! Very interesting, tnx!
Thanks, and you're very welcome!
Love these videos bro!!
Right on :D
I wonder how much CPU went for rendering and how much for computing? Would be interesting to see video side by side where on one side your current code fills screen and on other side entire number is calculated first and then everything is printed once and with no animation.
This video was very intriguing even though I understood under 10% of it. What level of computing do you learn related with the video? The only thing I understand is the Pi and the first part, and though I know nothing of this field, this does seem awesome
awesome video.
can you make a series where we can build a entire game? sprite, animations etc... i would pay for it.
I very much would like to do that, but it's a really big undertaking and takes quite a bit of planning :)
I thought from the title you would be making a mini NES out of a raspberry pie but this was cool!
could you do it in system ram if you just pushed a digit to the screen and reused the memory address or would that segfault / not render properly / still not enough ram for the code?
The spigot algorithm sure is interesting.
I approached the problem of calculating pi a bit differently back in the day when I were in high school and were bored.
I approximated pi by calculating the length of a very short triangle and then multiplied that by how much of a circle it represented.
It used a loop that started with a 90 degree corner.
Ie, point A at X=0 and Y = 1 and point B at X = 1 and Y = 0.
Find the center point C between these two point.
Draw a line from origin to C, extend until it is of length 1, this point is our new point A.
Repeat this n times.
Each time we get 2x closer to pi.
Our approximation of pi equal the distance from A to B multiplied by (4*2^n)/2
We started with a rather lack luster approximation of 2.8284, kind of far off.
The approximation is also always on the short side.
Is it a great solution? Absolutely not, it is really slow and you have to do a massive multiplication in the end, and the distance between A and B has to be of slightly higher accuracy as the number of digits you want in the result. (and working with huge numbers is a very efficient way to be slow...)
But it works and is simple enough to understand. Unlike a lot of more efficient and nuanced approaches that seem like magic in comparison.
Awesome, I've been meaning to do some non x86/non-desktop programming at some point, console is not a checkbox I've ticked yet, though I'm not quite sure I want to dive into assembly just yet, I'm working my way backwards. Though I guess the benefit of something like this is that its more pure, you won't have to disentangle some proprietary API such as what an xbox might have. Historically c wasn't used because it was slower? Is this still the case, how is c programming for something like the NES nowadays? Is inline assembly a good way to have the best of both?
You can do NES programming in C or Assembly, choice is yours. But some of the rendering stuff and advanced techniques requires precise cycle timing, so you have to break down into assembly to do that. I mostly teach assembly on the channel cause I think it's fun and a more natural way to program NES games.
quick question about the algorithm, if you need to store what base each digit is in, what makes the algorithm better than just storing all the digits in base 10? or is this just a proof of concept that the nes can indeed calculate the digits of pi 'by hand'?
This is just a guess but I suspect the games that run on the NES have the bases hard coded into them so no additional storage would be required.
Someone get standupmaths over here, he always does a special video for pi day
I think he's behind most of my favorite numberphile videos :)
i expected an other retro pie tutorial, good video
I had a thought when watching this video - If an NES is not equipped with logic to do something, a library can just be designed to do it? For instance, the SNES has something called mode 7, and this is a hardware feature that developers can call upon. For machines that don't have this hardware, like the Sega Genesis, can a library be designed to achieve it?
What if you did this on the SNES using its high-res mode? (512 dots plus 448 interlaced lines)
Nice video. Why do the divide algorithm for 2ⁿ values? I would have thought a shift right for the quotiant and a bit& for the remainder would work?
It's a divide algorithm in binary not for 2^n values. So it handles division between two arbitrary numbers.
@@NesHacker Ah, sorry. I thought I saw a "divide by 8/16", but it must be 8 / 16 width
Hey you could have done 1920 digits by using horizontal mirroring and scrolling down to the next nametable ;)
Indeed, but... At 1920 digits I'd need 2 × 1920 × 10 / 3 = 12,800 bytes for the array, which is 12.5 KB. With that number I'd need to use something like the MMC5 to fit the data into contiguous memory (I think you can map WRAM on an MMC5 board into $8000+ range, though I've never done it). Also it would take *much much* longer to compute, haha.
At this point using a 960 bytes table compressed to something like LZ4 would make more sense to extract all the Pi digits I think lol
Yeah I guess that would technically be "computing" the digits as much as this is...
@@NesHacker haha indeed :D
I tried implementing something like this on the GBA. It almost worked, but some of the digits are wrong since the algorithm outputs "10" as a digit sometimes. What did you do to fix this?
The little NES going "ano..." is so cute x3
That whole sequence had me laughing to hard when I was doing the graphics :D
Cool part: my birthday is on Pi day, 3/14
Nice, happy birthday :)
@@NesHacker Thank you :3
today i learned that by overloading my brain with such complex algorythm and sophisticated math at a faster pace
i can go sleep faster
Thank you for the great video
You're welcome :)
Great to see coders using assembler and struggling with little RAM. Back in the late 70s I did the same and resorted to using the video memory directly as storage. It’s been a while, but we have come a long way since 4k was total RAM.
Working in a more limited environment can be really fun because you often have to get creative. I didn't exist in the 70s, but I probably would have had a blast programming back then :)
If I remember correctly there is a fantasy console that has 1 kb of RAM.
Where in the Northeast is your Shack?
N.E.Shacker?
it could be possible for the nes to calculate the Fibonacci sequence?
Computing the Fibonacci sequence is kinda trivial compared to this. Even though it's inherently recursive, there's a *very* fast dynamic programming solution that requires storing only three variables.
the in real time showcase was so short, or is that bit at the end real time?
0:11 - all the digits of pi?
I haven't programmed 6502 assembly since the 90s on my C64, good memories. I had to do it on all on paper then poke all the bytes into memory with some C64 basic via the programmers ref guide, then call it with SYS xxxxxx. Hah, all that to make the text wiggle about on the screen or change char sets, make sprites. Fond memories.
hmm you could have a NesPi NesPi. any rom you make for the NES would run on the NesPi emulator (a raspberry pi running emulation station). double Nes Pi?
Can it really be seen as a general purpose computer tho if Nintendo decided what it ran, which was mainly if not exclusively games?
1:03 あのー (Umm)
フロップは何ですか? (What is flop?)
FLoating point OPeration
nice video! i love the idea of using old game consoles as general use computers. i wanna make something like this on the gameboy
The Z80 is for real, give it a shot :)
I subscribed!
I hope the algorithm bumps your video with March 14 around the corner.
This is so sick!
Haha, appreciate it :)