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Everything posted by SlithyMatt

  1. You need to enable the VSYNC IRQ, too. Enabling only the LINE IRQ messes up the kernal, which is expecting that VSYNC 60 times a second to keep it regular. It should only be disabled for short periods where you need to maximize CPU usage on some task, and don't care about I/O until it's done.
  2. I don't think there is any lack of open source 6502 assemblers, with ca65 and acme leading the pack. Compiling them to run on a native 6502 platform may be difficult, but they do compile just fine for any modern platform, and using sophisticated macro assemblers like these are going to really require cross-assembly from something with more horsepower than the X16. @mjallison42's assembler will be in ROM, and that's going to be hard to beat as an online (in the original sense!) option.
  3. I remember reading that DB25 ports were not used for Centronics parallel ports in Soviet computers - they had some other standard for printer connections. It may be a SCSI interface for a floppy drive, maybe even compatible with the FamiCom Disk System?
  4. Because the VERA doesn't have a CPU. To add the logic to do that would require a larger, more expensive FPGA, and at that point just stick the whole thing on an FPGA.
  5. Yes the SD is on the VERA daughter board, connected to the FPGA's SPI interface. However, there is no function built into the VERA to load data from SPI to VRAM. The SPI control just passes straight through the control register and is completely under control of the CPU. There's no VERA register that you can tell it "copy this file to this address of VRAM". It is much lower level than that. All the VERA does is bitbang the SPI based on what is written to the control register, and then shifts bytes in and out of the data register. The way the emulator cheats the file I/O for the convenience of using the host file system is not at all representative of how the hardware works.
  6. It's not pushed. The SPI interface doesn't run independently of the CPU. When a byte is pulled into the SPI_DATA register, the CPU needs to load it to a register to then store it in its final destination, whether that is RAM, VRAM, or some other I/O register.
  7. Like you say in the description, the physics make it even harder than the original Flappy Bird. You need to be able to slow down the falling. It's like gravity is about 50% too strong. Also, the original FB was kind enough to make the first few gaps a little wider.
  8. That's what I suspected. I know it works the same way when LOAD-ing to regular RAM. The emulator traps out the kernal call and just does an fread into the emulator RAM.
  9. Is that the case when using an SD card image, or just when using the host file system?
  10. Very interesting. Did you also try commenting out the #include <stdlib.h> as well? I wonder if cc65 has some weird black magic that affects what gets linked in based on mere #include statements, like some kind of library baseline and then additional code for each referenced function.
  11. My "Hello, World!" series is resurrected, this time for the ZX Spectrum:
  12. That will force you to link in a sizeable chunk (if not all) of stdlib. You could definitely roll your own pseudo-random algorithm in less space.
  13. I'll have to read through that, but have you considered making a video of you presenting this material? If I've learned anything, it's that there's a substantial audience for slide presentations on tech concepts on YouTube. Also, I humbly submit my own XCI game engine (https://github.com/SlithyMatt/x16-xci) as an assembly-like programming language that also lets people make games without programming experience.
  14. I don't think any of them are opposed to restoring common computers, like the C64 or Apple II. They are far more valuable in working operation. Something historic and rare like the Apple I would be a special case where it's too valuable as it is to modify, and nobody has one laying around that they want to get working again. That's why you see new PCB designs for making your own Apple I with off-the-shelf parts because nobody would dare tinker with a real one.
  15. In my newest vlog, I compare the ISAs of the 65C02 and Z80 to determine once and for all which classic 8-bit CPU is the GOAT!
  16. It's good to know that someone's not seeking to replace Gopher in 2021.
  17. Lesson 17: FM Synthesis
  18. Maybe the US government can buy whatever is left of Compuserve.
  19. In this week's vlog I answer questions from patrons, including going into why I got into the Commander X16 in the first place and what my plans are for more X16 games and content.
  20. He definitely has a big pile of dead 6510s, at least!
  21. I am considering getting a ZX Spectrum Next, maybe by the end of the series, depending on whether the series ends up being popular enough to justify the cost. If anybody has a NTSC Timex Sinclair 2068 they want to donate, I won't turn it down!
  22. See the video for the platform that will be the subject of my next assembly language tutorial series, programming for the other big 8-bit architecture.
  23. Why don't you just use the joystick API? It will automatically map to the keyboard if no controller is connected
  24. As there is conspicuously no G register on the Z80, you may be on to something here...
  25. New vlog on YouTube: If you wanted to see how to execute code in multiple segments of RAM with a single LOAD from BASIC, this is the video for you. See the description for the GitHub repo with example code and scripts.
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