Hello Long time ago, for my own purposes I tried to port amforth 1.6 to at90s8515 with external SRAM.
One thing was to port it to 8515 and another to replace all places where data is read by a custom function. You can have a look here: https://github.com/ytmytm/avr-amforth-90S8515 In forth.s there is a READ_WORD function that is called whenever a data or code is read. If the 15th bit is cleared then the read comes from flash, with 15bit set the read comes from external RAM. The nwords/ folder contains words that have to use READ_WORD. There is some code in istore.asm and the DP pointer is set to value $8130 with comment that it's $0260 in RAM, so I guess that all writes (data and new words) go to RAM. Best regards, Maciej 2015-01-27 2:16 GMT+01:00 Zbigniew <zbigniew2...@gmail.com>: > Hi! > > As an interesting exercise I'm going to recreate a little computer, > whose design has been published on pages > https://sites.google.com/site/retroelec/home > > There is a statement: "An ATMega microcontroller is a Harvard > architecture machine. So to be able to load and run arbitrary code > without reprogramming the flash memory the code has to be interpreted. > Therefore the ATMega emulates a 6502 processor (-> von Neumann > architecture)." > > The 6502 emulation the author created is pretty interesting thing, but > I would to use his design under Forth control, if possible - although > I'm aware, there'll be a need to add video routines etc. on my own, > and I hope to create all this exactly using Forth, not Atmel's > assembler. > > So my question is: is it possible for AmForth to use the entire > external SRAM area for both data and my own new words? You know, what > I'm after: to have "basic" Forth system burned into FlashRAM, and then > - as usual - to interactively develop the software for the little > machine using that 128 KB SRAM the guy selected for his design. > > Will it work the way I described? > -- > Z. > > ------------------------------------------------------------------------------ > Dive into the World of Parallel Programming. The Go Parallel Website, > sponsored by Intel and developed in partnership with Slashdot Media, is your > hub for all things parallel software development, from weekly thought > leadership blogs to news, videos, case studies, tutorials and more. Take a > look and join the conversation now. http://goparallel.sourceforge.net/ > _______________________________________________ > Amforth-devel mailing list for http://amforth.sf.net/ > Amforth-devel@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/amforth-devel ------------------------------------------------------------------------------ Dive into the World of Parallel Programming. The Go Parallel Website, sponsored by Intel and developed in partnership with Slashdot Media, is your hub for all things parallel software development, from weekly thought leadership blogs to news, videos, case studies, tutorials and more. Take a look and join the conversation now. http://goparallel.sourceforge.net/ _______________________________________________ Amforth-devel mailing list for http://amforth.sf.net/ Amforth-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/amforth-devel
