> how does a Forth interpreter work in a Harvard architecture microprocessor
You compile to "direct threaded code" in data memory; direct threaded code represents a sequence of calls as a sequence of addresses to call. So while "normal" threaded code (what Wikipedia calls "subroutine threading") would just have
call word_a
call word_b
call word_c
And then executing that means jumping to the first instruction, direct threaded code would have
&word_a
&word_b
&word_c
And then there's a suuuuper tiny runtime (like four of five instructions, literally) that has a "runtime instruction pointer" or whatever you want to call it, and just increments that and does an indirect call through to the next word whenever it's returned to.
You compile to "direct threaded code" in data memory; direct threaded code represents a sequence of calls as a sequence of addresses to call. So while "normal" threaded code (what Wikipedia calls "subroutine threading") would just have
And then executing that means jumping to the first instruction, direct threaded code would have And then there's a suuuuper tiny runtime (like four of five instructions, literally) that has a "runtime instruction pointer" or whatever you want to call it, and just increments that and does an indirect call through to the next word whenever it's returned to.