Hacker Newsnew | past | comments | ask | show | jobs | submitlogin

Same. I liked it on paper until I wrote code for it. Then I grew to hate it.

Wish WDC had made a "true" 16 or 32-bit 65xx. Forget the mode switching and extend the opcode set (by adding some two-byte instructions via a prefix-byte or something) to add additional 16 and 24-bit register access modes so one could get full linear 24-bit addressing. And let the direct page and stack sit anywhere in the 24-bit address space rather than just in the lowest page.

In the end I think the 65816 is mostly just a 6502 with some extra stuff bolted on the front of the instruction decoder. Quick and dirty, not much of a step up from the various 6502 + external bank switching we saw in the 80s.



I keep recalling that line from "The soul of a new machine" 'No mode bit.'


I briefly looked at what it would take to write a 816 backend for LLVM, and the mode bit significantly complicates things.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: