https://retroprogramming.iwashere.eu/ 2026-05-11T16:05:58+00:00 https://retroprogramming.iwashere.eu/ https://retroprogramming.iwashere.eu/lib/tpl/dokuwiki/images/favicon.ico text/html 2021-01-31T17:26:45+00:00 Anonymous (anonymous@undisclosed.example.com) https://retroprogramming.iwashere.eu/mt6502:blocking?rev=1612110405&do=diff Multithreading on retrocomputers BLOCKING AND NON-BLOCKING FUNCTIONS A protothread runs inside a single C function and cannot “span” on other functions. It can, of course, call normal C functions but, at the same time, it cannot block inside a called function. text/html 2021-01-31T17:26:18+00:00 Anonymous (anonymous@undisclosed.example.com) https://retroprogramming.iwashere.eu/mt6502:coordinate?rev=1612110378&do=diff Multithreading on retrocomputers COORDINATE THE PROTOTHREADS Protothreads are threads that run in a cooperative multithreading context. Protothreads voluntarily relinquish control once the current operation is over. More precisely, the scheduler passes control to another thread only in three cases: text/html 2021-01-31T17:25:58+00:00 Anonymous (anonymous@undisclosed.example.com) https://retroprogramming.iwashere.eu/mt6502:defining?rev=1612110358&do=diff Multithreading on retrocomputers HOW TO DEFINE A PROTOTHREAD The main advantage of protothreads over ordinary threads is that they are really lightweight: all protothreads run on the same stack, and the context switch coincides with the “rewind” text/html 2020-12-01T23:02:16+00:00 Anonymous (anonymous@undisclosed.example.com) https://retroprogramming.iwashere.eu/mt6502:helloworld?rev=1606860136&do=diff Multithreading on 6502/6510 retrocomputers "HELLO WORLD" WITH TWO PROTOTHREADS The code on tutorial_protothread1.c shows how to make two threads that, in competition, will access the CPU to print “Hello world”. To tell them apart, we'll add the protothread number at the bottom. text/html 2021-01-31T17:27:18+00:00 Anonymous (anonymous@undisclosed.example.com) https://retroprogramming.iwashere.eu/mt6502:locals?rev=1612110438&do=diff Multithreading on retrocomputers HOW TO MANAGE LOCAL VARIABLES Since protothreads do not save stack context, local variables are not preserved when protothread hangs. More correctly, the value of these local variables is undefined. This code, therefore, will never be able to run or compile correctly: text/html 2021-01-31T17:28:01+00:00 Anonymous (anonymous@undisclosed.example.com) https://retroprogramming.iwashere.eu/mt6502:midres?rev=1612110481&do=diff Multithreading on retrocomputers HOW ARE THEY IMPLEMENTED IN THE MIDRES LIBRARY? Protothreads are implemented with macros that represent “annotations”, using so-called “local continuations”. Furthermore, they can also be used independently of MIDRES' graphic primitives. text/html 2020-12-01T22:58:03+00:00 Anonymous (anonymous@undisclosed.example.com) https://retroprogramming.iwashere.eu/mt6502:walking?rev=1606859883&do=diff Multithreading on 6502/6510 retrocomputers ANIMATIONS USING PROTOTHREADS The code on |tutorial_protothread2.c shows how to make an animation with several autonomous actors, each managed by a separate thread. We will not comment on every single line but will limit ourselves to pointing out some fundamental points, to be explored. In particular, this tutorial uses the tiles and the rendering engine created for