3 ms·
Honest question: what exactly do you think is great about the 65816? Because I don't know much about the 65816 but I don't really see the appeal, even compared
by EdiX 11y ago
Honest question: what exactly do you think is great about the 65816? Because I don't know much about the 65816 but I don't really see the appeal, even compared to the 8086.
The 65816 had even less general purpose registers than the 8086, the Direct Page stuff seems like it would be a pain in the ass to use manually and a nightmare for compilers and the instruction set was already saddled with a rather awkwardly implemented backwards compatibility with the 6502 (set this two processor flags and now you are running on a 8bit processor instead of a 16bit one!)
- cmrdporcupine 11y agoFrom what I understand the advantage the 65xx had over the 8008/8080, and Z80 back in the day was a) price and b) way better cycle efficiency and c) faster interrupt response. The 6502 could often do in 1 cycle what a Z80 took 4 cycles to do. An 8-bit memory read or write was 1 cycle. For 8-bit home computers mostly used for graphics and games, that's cool cuz you got good performance per dollar. I guess 65c816 kept that speed and its simplicity and offered an upgrade path. But only the IIGS and the SNES used it. Direct page is pretty cool when you consider that the cost of a memory access was 1 cycle. So it's effectively 256 extra registers (tho still only one ALU).