frans@philmds.UUCP (Frans Meulenbroeks) (07/24/87)
Hi! The other day I dug up an article in EDN (jan 9, 1986, p. 216-9) concerning an upgrade from 68000 to 68020. Only a little glue is required. It also seems that the german magazine C'T describes such a board in their August issue. They claim a performance improvement between 30 and 40 %. They are selling a print for about 50 German Marks ( 25 dollar) The rumour says they can also handle a 68881. Sorry, no address. Implementing such an upgrade may cause software problems in the ST. Currently I recognize the following problems: - Exception frames are different. I think this can be overcome by writing an own exception handler, which "transforms" the 68020 exception frame into an 68000 one, and then calls the appropriate BIOS routine. - timing problems. I noted that there are some delay loops in the very beginning of the bios (notably in the code for the floppy) These loops have to be increased or an interrupt driven operating system has to be used (MINIX?!) And now for the question part: Has anyone experience with such an upgrade? Does anyone see other problems (especially in the software area)? -- Frans Meulenbroeks Philips Distributed Realtime Multiprocessor System uucp: for the time being: philmds!frans