Oops. And the digression was caused by me. FWIW, my excuse is that Self Modifying Code has gotten a lot of bad PR, and I feel the best way to overcome that is to show SMC being used in a clean and tidy way. When your example of SMC also happened to include hand calculated offsets I felt compelled to speak up, because the two do NOT go hand in hand.

Yes, you have a solution of sorts but it's not one I like much, and I thought perhaps I could do a little better.

Unfortunately, after refreshing myself on the subject (it's been years since I involved myself with this) I have no dramatic improvement to offer. In my notes I did find the following...... but this is less flexible than what you're doing, and certainly no prettier.

cheers,
Jeff

ps: returning to the subject of clean and tidy coding, don't you think you should used a named constant in cases like this?

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What's an additional VIA among friends, anyhow?

You are correct, I should have. I wasn't thinking about it but, those who downloaded the first ZIP file are limited to 'fair use' of copyright law. The first one has been replaced with a ZIP file containing the assembler and a copy of the LGPL version 2.1.

Well, it's one of those locations used by the C64 kernel and I didn't want to add a constant to my Forth kernel that would only be used once.
I suppose I could add a constant that exists on the host but not the target. Since it's only used once in the entire Forth kernel, would a comment do?
The Commodore 64 Programmers Reference Guide calls location $98 LDTND number of open files/index to file table, and locations $259-$262 LAT Kernel table: active logical file numbers.

Since the conditional has to be there to determine which branch opcode is compiled by WHILE, , and IF, , I tend to see the conditional as part of the WHILE,. That's why I put it on the same line.

If I understand your assembly notation, shouldn't this:

be this:

or something similar?

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

That doesn't really bother me, as long as the indentation correctly shows the control flow nesting.

I really shouldn't post when I'm tired. I do use SUB in my kernel source. Before that, I used LABEL ( makes a metacompiler label ) and invoked the assembler directly. SUB was so much easier.

I made some improvements to my metacompiler. With INCLUDE , it can take this sequential file from a C64 disk and compile it with no Forth, no headers, just the assembly code. It then prompts for a filename and spits out a binary to the disk. The demo does what some programs meant to be called from BASIC does, SYS 49152 does one thing and SYS 49155 does another.

Changes to the Fleet Forth kernel necessitated changes to the definitions of CODE , ;CODE , and END-CODE .
Here is the new source

As for SUBR , well, some Forth's have code like this:

to create subroutines. SOMENAME returns its address and is used like this:

or, depending on the assembler, like this:

SUBR creates a subroutine without the need to explicitly setup the assembler.
All such subroutines are concluded with END-CODE .

Since defining a constant in the target source builds that constant in the target, I added DEFINE to my metacompiler. It builds a constant on the host so no memory is used for it on the target.

P.S. It may take a while to cleanup all of Fleet Forth's source code, but the improved readability will be worth it.

Cheers,
Jim

I renamed the metacompiler's SUB to SUBR for consistency with the host assembler. Why SUBR over SUB ? To avoid confusion if this Forth assembler macro is ever defined:

The metacompiler's SUBR creates a label on the host ( in the shadow vocabulary ) that returns the virtual address of the subroutine on the target, but no header or CFA is compiled on the target, only the subroutine.

And what op-code do you comma in for that one?

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Got a kilobyte lying fallow in your 65xx's memory map? Sprinkle some VTL02C on it and see how it grows on you!

Mike B. (about me) (learning how to github)

_________________
http://WilsonMinesCo.com/ lots of 6502 resources
The "second front page" is http://wilsonminesco.com/links.html .
What's an additional VIA among friends, anyhow?

[OT] Amen. I have a gigantic pile of "stuff" that needs my attention. I often get a feeling of being lost under the weight of it all, and I don't even have the fortitude to at least nibble away at it, which would be better than trying to pretend that it's not there ... [sigh]

_________________
Got a kilobyte lying fallow in your 65xx's memory map? Sprinkle some VTL02C on it and see how it grows on you!

Mike B. (about me) (learning how to github)

I didn't mention it ( although it's in the source code ) but my assembler has the word BRAN, which takes an address and a condition code from the stack. As an example of how it works, here is the source for Fleet Forth's S>D

PUSH.TRUE and PUSH.FALSE are metacompiler labels for the locations where a true and a false respectively are pushed onto the data stack.
TRUE and FALSE have no bodies. Their code field's point to these locations so S>D could have been written as

BRAN, and all the words that compile or resolve a branch perform distance checking and abort if the distance is too far. I was motivated to add this when I was working on that word that takes a 64 bit unsigned number and returns the square root as a 32 bit result.