A risc-v update.
AmForth-RV update
Good progress made with the CH32V307 [0]
Words defined in the RAM dictionary can now be appended to the FLASH
dictionary so user defined words (individual words or the entire RAM
dictionary) are able to survive a reset. This was one of my major
milestones and (in my mind) a requirement for a self-hosted Forth. I
was not able to achieve this with the FE310 based red v board.
Additionally, something new to AmForth. Compiled C objects can be linked
into AmForth-RV and called from within CODEWORDs. This is a build
level modification and arguments are passed to the C function using
assembly according to the risc-v calling convention.
The CH32V307 makes a very good target mcu for AmForth-RV and for
experimenting with embedded RISC-V in general.
- The development board is inexpensive and available [1] [2]
- There is official documentation and many 3rd party resources
- The mcu can program its own flash whilst executing from flash
- AmForth-RV can be built with an open source toolchain (build in < 3s,
flash in < 6s )
If you are interested in trying some risc-v hardware I think it is a
good choice.
AmForth-RV is still experimental, but has made a step in the direction
of being less so. There are quite a few decisions to be made, so any
thoughts on what AmForth-RV might look like in the future are very much
welcomed.
Best wishes,
Tristan
[0] https://github.com/openwch/ch32v307
[1] https://wchofficialstore.aliexpress.com/store/1100367542
[2] https://www.aliexpress.com/item/1005004329125620.html
(and many other suppliers)
A brief annotated/edited session showing saving a RAM dictionary word.
// see if a word 3+ has been defined //
ok
show 3+
LFA..... (LFA)... FFA..... (FFA)... NFA..... XT...... (XT).... word....
ok
// no it has not, so define it in the RAM dictionary //
: 3+ 1+ 1+ 1+ ;
ok
// and see that it exists //
show 3+
LFA..... (LFA)... FFA..... (FFA)... NFA..... XT...... (XT).... word....
20003A54 200039B4 20003A58 00000000 20003A5C 20003A60 COLON 3+ (in
RAM)
ok
// now append the word 3+ to the FLASH dictionary //
save 3+
3+ HHHHBBBB 3+
ok
// and see that it exists //
show 3+
LFA..... (LFA)... FFA..... (FFA)... NFA..... XT...... (XT).... word....
0000D200 0000D094 0000D204 00000000 0000D208 0000D20C COLON 3+ (in
FLASH)
20003A54 200039B4 20003A58 00000000 20003A5C 20003A60 COLON 3+ (in
ROM)
ok
// it does, twice, once in RAM and once in FLASH //
// reset the board //
AmForth-RV 7.0 RV32IMAFC WCH CH32V307
Fri 19 Jan 2024 16:46:34 GMT
// see if 3+ exists //
words
3+ forth-wordlist environment riscv-wordlist @cycle type0
hifive-turnkey rev-info build-info mtimecmp mtime led.init -led +led
forth-wordlist >flash.p ram>flash flash>ram ram>rom rom>ram
// see if it works //
100 3+
ok
u.
103 ok
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