I'm not sure why I chose null-terminated initially. Probably because
the z80asm version had null-terminated strings.
Length-prefixes strings are the traditional form of strings in Forth
and it's a bit easier to work with them with traditional forth words
when they're under this form.
During "make updatebootstrap", we use less than 0x20 bytes on the
PSP side and less than 0x40 bytes on the RSP one. 0x100 bytes ought
to be enough for anybody.
XPACKed source needing to be kept in bootstrap bin didn't make
much sense. With the removal of stripfc, it makes more sense to keep
the compiled form of stage 1 in repository as a bootstrap binary.
Also, rename it to forth.bin.
Make LATEST configurable through a value in the binary instead of through
a ZASM constant. This enables the simple concatenation of compiled dicts and
simplifies the build process.
This allows us to save a whole 500 bytes on the final binary size!
This change comes after I took a look at the hex dump and saw that one letter
constants in z80a.fs took a lot of space.
My approach with RS was slightly wrong: RS' TOP was always containing current
IP. It worked, but it was problematic when came the time to introduce
RS-modifying words: it's impossible to modify RS in a word without immediately
messing your flow.
Therefore, what used to be RS' TOS has to be a variable that isn't changed
midway by RS-modifying words. I guess that's why RS is called *return* stack...
Big one.
This allows us to write higher order words directly in Forth, which is much
more convenient than writing post-immediate (see "NOT" structure in diff if
you want to see what I mean) structures in ASM.
These structures can then be written to ROM (rather than loaded in RAM for
definitions loaded at run-time).
That's quite a bit of tooling that was added, 2 compilations stages, but I
think it's well worth it.