7 ms·
Sort of what the MC68008 was ages ago: 32 bit internal architecture but reduced external data and address buses so the chip could be used to build simpler/cheap
by squarefoot 7y ago
Sort of what the MC68008 was ages ago: 32 bit internal architecture but reduced external data and address buses so the chip could be used to build simpler/cheaper systems.
- Taniwha 7y agoI think it's more like a 16-bit internal architecture and buses - so PDP-11 sized, add a rudimentary base and bounds swapping MMU and you have enough to run unix
- messe 7y agoRetroBSD would probably be a good starting point for anybody interested in porting a unix to this device. It's based on 2.11BSD (a backport of 4.3BSD features to the PDP-11) I've looked into porting it to the Nintendo DS. It should be doable, but I haven't had the time to commit to it. Maybe I'll give it another look this weekend.
- _0ffh 7y agoOr the 8088, 16 bits internally, but external buses (memory, port i/o) only 8 bits wide?
- vardump 7y agoMC68008 was internally 16-bit. 16-bit "add.w d0, d1" takes 4 clock cycles and 32-bit "add.l d0, d1" takes 8.
- monocasa 7y ago32-bit internal architecture here meaning 32-bit registers, and a greater than 16-bit address space (yeah it's not full 32-bit, but neither read the full 68000).
- vardump 7y ago68000 was a 32-bit ISA, but with 16-bit internals, mainly meaning ALU. 32-bit register file, flat 32-bit address registers (pointers). Moving data with move.l and move.w between registers was both 4 clock cycles. I wrote a ton of assembler on 68k back in the days and absolutely loved the large orthogonal register set and useful addressing modes. Going to x86 was rather painful after that. :-) Some ways 32-bit, but 16-bit level performance. I think in the end you can call it either way.