mikaelpatel / arduino-fvm Goto Github PK

This issue is a list of missing words (Forth94 Core).

' NAME ( -- xt )
['] NAME ( -- xt )
unloop ( -- )
*/mod ( n1 n2 n3 -- n4 n5 )
2! ( x1 x2 a-addr -- )
2@ ( a-addr -- x1 x2 )
2>r ( x1 x2 -- )
2r> ( -- x1 x2 )
2r@ ( -- x1 x2 )
cell+ ( a-addr1 -- a-addr2 )
count ( c-addr1 -- c-addr2 u )
c>s ( c-char -- n )
fill ( c-addr u char -- )
fm/mod ( d1 n1 -- n2 n3 )
m* ( n1 n2 -- d )
um* ( u1 u2 -- ud )
um/mod ( ud u1 -- u2 u3 )
scan => word ( char -- )
compile NAME => postpone NAME 
lookup => find ( c-addr -- c-addr 0 | xt 1 | xt -1 )
>number ( ... )
:noname ( -- xt )
marker NAME ( -- )
value NAME ( x -- )
[compile] NAME 

Support 32-bit MCU based on ARM core such as Arduino Due. These have the advantage of much more memory and allow symmetrical memory model (i.e. data structures in RAM).

Add virtual machine instruction to allow call of C/C++ function. Use same structure as for CREATE-DOES>, VARIABLE and CONSTANT.

Performance optimization: jump to function instead of call, avoid exit to exit return. See also https://en.wikipedia.org/wiki/Tail_call.

The AVR is a Harvard Architecture with separate memory spaces (SRAM, EEMEM, PROGMEM). To allows threaded code in all memory spaces a synthetic unified address spaces is needed. This will impose a run-time penalty on the inner interpreter and any operation that access the instruction pointer, i.e. branch, literals, etc.

http://forth-standard.org/standard/alpha

This project looks like it could be useful - what license are you using?

tos is pushed and poped from parameter stack on context switch. ip is not, it is stored in the context struct, but should for symmetry be also pushed and poped from the return stack.

The current token mapping allows for at most 128 kernel and 128 application words. Byte positive values (0..127) are for kernel implementation and negative (-128..-1) for application.

The screenshots in the README have broken links.

/home/ga/Arduino/sketches/libraries/FVM/src/FVM.cpp: In function 'int8_t fetch_byte(FVM::code_P)':
/home/ga/Arduino/sketches/libraries/FVM/src/FVM.cpp:105:31: internal compiler error: in type_hash_canon, at tree.c:7158
if (ip < (FVM::code_P) FVM::CODE_P_MAX)
^~~~~~~~~~
Please submit a full bug report,

The bug has been logged with GCC: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94437
In the meantime, I have a patch available to work around it.

Arduino have defined a new architecture, megaavr, for the ATmega4809 chip on this board.
There are some minor code changes needed to make it work. Patch available.

Allow the scanner to be configured to echo all characters read during the parsing of a word.

Compile forth statements to virtual machine instructions (in C++).

Use the Compiler to generate code for some of the example sketches, i.e. Blink.

The VM is byte coded and allows for 256 tokens. The inner interpreter uses signed byte to determine if the token is executed direct (C++) or threaded call. To extend two special tokens are used. These allow the token value to exceed -128..127.

Kernel tokens are 0..127 direct, 128..255 extended.
User tokens are 256..383 direct (mapped to -1..-128), 384..511 extended.

The token space is not continues. There exists illegal tokens that needs to be captured.