Can You Write 8-bit Code?

Have you ever tried to write software for a 6502 or other 8-bit processor? I tried so many times, since I was a child, to write anything of significance, and it is just so tedious. Nowadays, I’m curious the sort of psychology of someone who wants to go all the way back to the 8-bit days, vs. my preference for the m68k 32-bit era.

Stefany Allaire’s current 8-bit retro computer is called the F256K, and it was the machine that got me thinking along the lines of buying her 68040V-based A2560K-040V instead. The 68040V is a low-power version of the 68040, without the FPU, but with the MMU. It’s understandable that it’s hard to source the faster 68040 CPU SKUs in sufficient quantity to sell, considering that it hasn’t been manufactured in how many years?

The train of thought that led me to want to port AROS to the A2560K-040V started with me thinking of trying to write something like AROS or AmigaOS for the F256K. I was thinking about the 65C816 variant, but unfortunately, the F256K is optimized for the 64KB address space of the 6502 in the base model.

That led me to want to pose the question: would you willingly submit yourself to the limitations of a 64KB address space, with bank switching to access larger amounts of RAM and I/O space, and an 8-bit CPU with such limited capabilities? It’s actually more restricted than, say, a Z80, the preferred CPU for CP/M.

I actually went through the process of thinking about how to port something like AmigaOS to the CPU that’s in the Commodore 64, which reminds me, did you know that a hobbyist wrote a new C64 OS? It’s really clever. Using the text mode with a custom character set saves precious RAM. But it’s kind of a nightmare to think about writing something like that oneself, at least for me.

Once I realized the 68040 was exactly my speed, and that AROS on a different m68k machine would be binary compatible with “well-behaved” (not accessing the hardware directly) Amiga programs, I decided to target the A2560K-040V, with the QEMU emulation of the Mac Quadra 800 as my testbed to make sure it’s worth it for me to spend the money for the real hardware, which is tantalizing in its custom FPGA-based capabilities.

After Commodore went bankrupt in May 1994, a number of companies acquired the intellectual property, and most of the interest during that decade seemed to be on making PowerPC-based “Amigas”, without the original custom chips, which really are very much tied to their era (the timing is all based on either PAL or NTSC analog RGB CRT output).

I can understand the appeal of wanting the faster CPU, but then you get away from the simplicity of the m68k that is a large part of its charm. There are all sorts of accelerator cards for the Amiga, including adding a PowerPC to an existing one, and they’re all incredibly expensive, and the 1990s-era Amigas and cards are getting unreliable due to the age of the components.

Thus my interest in a “new old” computer. Ms. Allaire and I are on the same wavelength. I hope I can port an OS of a quality to match the hardware design, and that will in turn attract application developers to buy it and write games and other apps for AROS. Abstracting the hardware features in an OS-friendly way will be a fun exercise.

What era of computing power are you most comfortable with?







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