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FORTH for the SHARP PC-E500 (S)
10-06-2021, 02:41 PM
Post: #21
RE: FORTH for the SHARP PC-E500 (S)
(10-05-2021 01:02 PM)Klaus Overhage Wrote:  In RUN mode: COPY "COM:" TO "E:debugger.fth",A
In Forth500: INCLUDE debugger.fth
Loading debugger...
-- after 90 second --
Loading debugger... Exception #-13

Exception #-13 stands for "undefined word"

The large debugger.fth is the one and original code example that S├ębastien wrote for pceForth. It meta-interprets Forth to debug Forth. I made a minor change to it, but have not yet tested it. The debugger.fth file has a disclaimer:

\ Updated to Forth500 but may need some more testing!

When an error occurs, the error occurs in the definition of the first word displayed by WORDS. The definition is incomplete, so it cannot be executed. But WORDS displays all words, including incomplete ones.

There should be a better way by adding some code to display the -13 error message with the word that wasn't found. I will add that to my TODO list. The parsed input from a file is stored in the FIB buffer at position >IN.

Also, INCLUDE does not catch exceptions so the file may still be open and not closed. The file must be closed to read it again, e.g. try 4 CLOSE-FILE to close the fileid (typically 4). I will look into this too, to close automatically.

It would be nice to add more examples and additions to Forth500. For example, implementing SEE would be nice, e.g. to load from see.fth. These words should be optional, otherwise adding these as built-ins eats away free space. On an unexpanded machine the Forth500 free space will be about 7K after adding the floating point words. I don't want to push that down much lower. It was possible to reduce Forth500 below the 20628 bytes that pceForth required. I am pleased with that, because Forth500 adds words and new features (see the changelog in the repo).

- Rob

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FORTH for the SHARP PC-E500 (S) - Helix - 09-06-2021, 11:41 PM
RE: FORTH for the SHARP PC-E500 (S) - robve - 10-06-2021 02:41 PM

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