Instead of going left and right, finding operators chars and replacing them
with nulls, we parse expressions in a more orderly manner, one chunk at a
time. I think it qualifies as "recursive descent", but I'm not sure.
This allows us to preserve the string we parse and should also make the
implementation of parens much easier.
This should make tests a bit more convenient to write and debug.
Moreover, begin de de-IX-ization of parseExpr. I have, in a local WIP, a
parseExpr implemented using a recursive descent algo, it passes all tests, but
it unfortunately assembles a faulty zasm. I have to find the expressions that
it doesn't parse properly.
But before I do that, I prefer to commit these significant improvements I've
been making to tests harness in parallel of this development.
Use IX directly for argspec rows instead of going through DE. It saves a bit
of processing. The code was this way because I initially didn't use IX at all,
so as code evolved, that DE translation stayed as an artifact.
That's my mega-commit you've all been waiting for.
The code for the shell share more routines with userspace apps than with kernel
units, because, well, its behavior is that of a userspace app, not a device
driver.
This created a weird situation with libraries and jump tables. Some routine
belonging to the `kernel/` directory felt weird there.
And then comes `apps/basic`, which will likely share even more code with the
shell. I was seeing myself creating huge jump tables to reuse code from the
shell. It didn't feel right.
Moreover, we'll probably want basic-like apps to optionnally replace the shell.
So here I am with this huge change in the project structure. I didn't test all
recipes on hardware yet, I will do later. I might have broken some...
But now, the structure feels better and the line between what belongs to
`kernel` and what belongs to `apps` feels clearer.
Most of register fiddling routines (which is now the only thing contained
in care.asm) are used by almost all userspace apps, often in inner loops.
That makes the penalty of using jump tables for those a bit too high.
Moreover, it burdens jump tables needlessly.
Because this unit is very small (now that string routines are out), it makes
sense to always include it in binaries.
There's a couple of bit fiddling instructions that didn't have their
IX/IY variant implemented yet and without this commit, each of them
would have required a special routine. Not anymore.
During expression parsing, if a local label was parsed, it would
select the local registry and keep that selection, making
subsequent global labels register in the wrong place.
This huge refactoring remove the Seek and Tell routine from blockdev
implementation requirements and change GetC and PutC's API so that they
take an address to read and write (through HL/DE) at each call.
The "PTR" approach in blockdev implementation was very redundant from
device to device and it made more sense to generalize. It's possible
that future device aren't "random access", but we'll be able to add more
device types later.
Another important change in this commit is that the "blockdev handle" is
now opaque. Previously, consumers of the API would happily call routines
directly from one of the 4 offsets. We can't do that any more. This
makes the API more solid for future improvements.
This change forced me to change a lot of things in fs, but overall,
things are now simpler. No more `FS_PTR`: the "device handle" now holds
the active pointer.
Lots, lots of changes, but it also feels a lot cleaner and solid.
This allows us to break through the 64K limit for includes CFS in zasm,
a limit we were dangerously close to breaking. In fact, this commit
makes us go over that limit. Right in time!
