Bitwise Logic - 6502 Assembly Crash Course 04

In this part of the 6502 Crash Course I introduce you to bitwise logic operations, explain how they work, and show some practical ways to use them in your own games.

Chapters:
0:00 Introduction
1:31 Perspectives on Data
3:22 Logic Operations
4:39 Bitwise AND
6:55 Bitwise OR & Exclusive OR
8:30 Example: Testing Bits
11:23 Example: Flipping Bits
13:24 Coding Challenge
14:00 Conclusion

[NesHacker]

This was a lot of fun but pretty tough to make, let me know if it helped you understand bitwise logic. Also, stay to the end of the video for a programming challenge!

[jwalshmorrissey]

This series is fantastic. The production is top-notch, and you clearly either have a background in education or a strong aptitude in that area. (My opinion as a former college professor.) I considered leaving the feedback that each video in this series could be literally twice as long, not because you don’t explain adequately, but simply because the pace is extremely fast. It’s easy to follow along superficially, but too quick to really assimilate the information for most people, especially the novices you’re addressing. But now I think that the use case is such that the viewer can simply pause and rewind as needed. That’s what I’m doing as I delve into the 6502.

This channel should be MUCH bigger. Keep up the excellent work. You exude intelligence and competence, and I’m sure you’ll reach a broader audience.

[SoulcatcherLucario]

this series has been invaluable as someone who although is a software dev by trade, only has experience in very _high_ level languages. i had my mouth open the entire time because of how well you explained this.

i really hope you continue making these videos, because this combined with easy 6502, i feel much more safe dealing with assembly.

[RealSpectrum]

I hope you keep going with these videos, I feel like I've learned more on your channel than I did in 3 and 1/2 years of computer science classes in academic settings

[AT-zrtv]

Great video, super easy to follow and exciting to see the direct use in gameplay.
Regarding your exercise: say we want to only flip bit0, the exclusive OR against bitmask %0000 0001 will flip bit 0 and leave all 7 other bits unchanged.

[Pesgaming]

Top notch video. Thank you. Simple and effective

[hicknopunk]

Heck yeah! Thanks so much for more 6502 stuff. 😍

[ChrisBouchard]

Very nice video! I'll just mention for anyone reading: I'd usually use the term "bitmask" to refer to what this video calls an "isolation mask", and "bit string" or "bit field" for what the video calls a "bit mask". It probably depends what programming communities we learned in.

[kirbylouise]

LDA $40
EOR #%00001111 '(or just a 1 wherever you want to flip)
STA $40

On a side note, it's interesting that EOR is used in favor of XOR for the exclusive or mnemonic. Perhaps the 6502's designers were fans of winnie the pooh?

[Favourites]

Excellent stuff man. The videos keep getting better, more interesting and even easier to follow!

[madcorndog]

We need more tutorials! These are the only actually watchable tutorials for NES programming I found. I learn programming languages best with youtube tutorials and I would love to learn how to make a fully fledged nes game.

[bcchithrck]

been waiting for this. thanks for the lesson and high quality vid!

[Wineman]

Smoke, smoke is coming out of my ears!!!.
Last time I made a program was over 26 years ago.
That was on an ancient computer used in a class in the Navy on programming.
First program I wrote was a diagnostic program to test for shorts that the instructor would place on a random pin on the main board.
The peripheral was these awful dinged out monochrome screens that were impossible to read.
Yeah programming I could do but for only the basic stuff for fixing things in the field.
Love your videos man thanks for what you are doing.

[kamara]

I've really enjoyed the videos and learned a lot. Please keep going and I'm sure your channel will grow in no time

[kythrathesuntamer]

You're actually producing some of the most helpful content i've run across on YouTube, I jsut wish you would keep going. I

[mysteryemblem]

Enjoyed the content of the video. I'm not making a game, but I like to learn how a hardware, or a computer work behind the scene.

[marcelomarcon]

Its a great series of videos, please explain what is each register for, and how it can be used, PC, AX, BX etc...

[amaiorano]

Fantastic video, and series as a whole! My one nit: what you call a bit mask is really a bit field. The mask is what's used to set or read the bits of a bit field. Anyway, thank you for making these!

[ebanavorio]

XOR 1
This series is just magnificent

[AsciiKing]

I'm really enjoying this series. I had to pause the video to tell you that loud music makes it extremely difficult for me to focus on what you are saying. My brain actively listens to the music. This was a very difficult video for me. Also, at 2:02, you say 'four two-bit numbers' when you meant, 'two four-bit numbers'.