11–20 of 127 posts
https://github.com/jhallen/exorsim
8 inch floppies! I remember we had an old GE chain-train printer for it which was awesome because it was so fast.
I built a small multitasking kernel with a friend with a 68000 (m68000) in college. We implemented it on breadboards, I think with 30 or so feet of jumpers [0]. I had very little prior embedded experience, so it was trial by fire. It was a wonderful introduction to how kernels work (or at least concurrency and scheduling) at their most basic level, without having to deal with the complexity of virtual address spaces,…
I built a small multitasking kernel with a friend with a 68000 (m68000) in college. We implemented it on breadboards, I think with 30 or so feet of jumpers [0]. I had very little prior embedded experience, so it was trial by fire. It was a wonderful introduction to how kernels work (or at least concurrency and scheduling) at their most basic level, without having to deal with the complexity of virtual address spaces,…
The 6800 is nothing like the 68000.
I built a small multitasking kernel with a friend with a 68000 (m68000) in college. We implemented it on breadboards, I think with 30 or so feet of jumpers [0]. I had very little prior embedded experience, so it was trial by fire. It was a wonderful introduction to how kernels work (or at least concurrency and scheduling) at their most basic level, without having to deal with the complexity of virtual address spaces,…
I built a small multitasking kernel with a friend with a 68000 (m68000) in college. We implemented it on breadboards, I think with 30 or so feet of jumpers [0]. I had very little prior embedded experience, so it was trial by fire. It was a wonderful introduction to how kernels work (or at least concurrency and scheduling) at their most basic level, without having to deal with the complexity of virtual address spaces,…
With the optics of _compiled_ code, how do the various 8-bitters stack up? (6809/6811, 65C02, Z80, H8, ...)? One would have to account for the frequency allowed by the ISA at iso-technologies (which makes including AVR somewhat tricky). I only have experience with Z80 and 65C02 and I believe the consensus is that a 4 MHz Z80 beats a 2 MHz 65C02, but neither is a particularly nice compiler target.
I just don't think any of the 8-bits made good compiler targets. At least not C compilers. Not enough registers, even in the 6809.
With the optics of _compiled_ code, how do the various 8-bitters stack up? (6809/6811, 65C02, Z80, H8, ...)? One would have to account for the frequency allowed by the ISA at iso-technologies (which makes including AVR somewhat tricky). I only have experience with Z80 and 65C02 and I believe the consensus is that a 4 MHz Z80 beats a 2 MHz 65C02, but neither is a particularly nice compiler target.
I just don't think any of the 8-bits made good compiler targets. At least not C compilers. Not enough registers, even in the 6809.
Earlier quoted context omitted.
The 6809 had two 16 bit index registers, PC-relative addressing, and upper half of the stack and data page address was taken from special purpose registers instead of hardwired. It should be a fairly straight forward compiler target. On the other hand it was late to the game, expensive and not (much) faster than 8bit microprocessors. The 6502 very cheap, fast enough when it came out, but a really annoying compiler ta…
I had a TRS-80 Color Computer when I was kid which had one major drawback: it could only display 32 characters across the screen compared to 40 characters for the Apple ][, C64 and most others at the time. The Coco could run an operating system called OS-9 which was Unix-influenced and came with a good C compiler and also a bytecode interpreted structure basic called BASIC09. I know C compilers were really popular am…
There was an external serial port as an option, but there was only one slot. So you also had to buy a slot expander (a Multi-Pak).