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Learn BASIC and 6502 Assembly with bite-sized video tutorials.
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Season 10 - Stable Raster & Opening Borders

Here's what you will get

  • 9 videos (50+ minutes in total)
  • transcripts (13000+ words)
  • source code examples (10000+ LOC)
  • access to 64bitesVIP Facebook group, where you can get help
  • plenty of exercises to solve on your own
  • online streaming
  • download with no DRM
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Buy Season 10 for just $19.99 $13.99

Includes 9 videos, detailed transcripts, source code examples and exercises.

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All Episodes in this Season

Episode #090 - Sprites on the border II - Seven sprites

In the previous episode, we have learned that if the sprite is to be displayed on a next raster line the graphical chip steals five cycles from the processor. That's not the whole story, though. Not all of those five stolen cycles are equal. The number changes depending on which sprites are currently active. Today we will try to figure out the required delay for up to seven sprites.

Episode #089 - Sprites on the Border I

Now that we have the border open around the whole screen, we can finally use that space to draw something. We can use sprites to do that. But having them enabled with the side border open is actually quite hard. Today we will see how to display them on separate raster lines.

Episode #088 - Hyperscreen

In this episode we will learn two methods of opening all borders around the screen. The effect is also know as hyperscreen because it allows to expand the drawable area and increase the screen resolution.

Episode #087 - Opening Borders III - Almost There

In the previous episode, we've started opening side-borders. It went fine until weencountered a bad line, which left us with fewer cycles to spare. Today we will tackle that problem and try to open the rest of the border.

Episode #086 - Opening Borders II - Left & Right

In the episode sixty-one, we've learned how to use the vertical border expansion to remove parts of the border that are above and below the drawable area. Opening side borders can be accomplished in a similar fashion, but it is significantly harder. Not only the timing has to be spot-on, the process has to be repeated on each raster line.

Episode #085 - Raster Stabilization IV - Pitfalls

We've been working on a raster stabilization routine for three episodes already. We ended up with an optimized code that does the job quite well. But I've also been warning you about difficulties in writing timing specific code. Today we will explore the topic, and try to break our routine deliberately.

Episode #084 - Raster Stabilization III - Optimization

Once we have our stable raster routine working it's time to optimize it. Let's see if we can minimize its memory footprint and shave off few cycles here and there.

Episode #083 - Raster Stabilization II

In this episode we continue stabilization of the raster. All we need to do is solving two problems: * find out a way to detect if we are one cycle early and then * delay the execution by just one cycle only in this situation. The former can be solved by comparing current rasterline register value at the right moment. Once we know that we need to just find an instruction that can take a variable amount of cycles. But how to do it in practice?

Episode #082 - Raster Stabilization I

Because of the way the 6510 processor works the raster interrupt handlers might experience a random delay in execution. The variance is usually called the jitter and it can take up to seven or even eight cycles. In this episode we will learn how to reduce the jitter to only one cycle consistently using two nested interrupts.