Things are better now, but immediates inside colons are broken. However,
IF/THEN/ELSE are now immediates and it's much cleaner this way. Still, this
commit has too much stuff in it, I need to commit, I don't want to lose this
step.
The goal was to be able to implement "(" in forth, but I realised that my
INTERPRET approach was wrong. Compiling the line beforehand is, after all,
not good. I'll have to change it again.
Previous approach was broken with regards to defined word using CREATE.
Also, reduce name length by one to make space for a new flags field for
"immediate" (which isn't used yet).
This scheme of "when we handle line-by-line, compile one word at a time then
execute" so that we could allow words like "CREATE" to call "readword" before
continuing was a bad scheme. It made things like branching outside of a colon
definition impossible.
This commit implement a new "litWord". When an undefined word is encountered at
compile time, it is included as-is in a string literal word. It is at run time
that we decide what to do with it.
Not much of a gain in terms of usability (a bit of a loss in fact, things are
a bit slow and glitchy), but it's a necessary move if we want to use upcoming
grid-enabled userspace apps, such as a visual text editor.
Sending the escape after its target made things complicated for upcoming
stuff I want to add. Although it makes `recv.asm` slightly larger, it's really
worth it.
* String functions optimised
A few functions have been tweaked, but the biggest changes are in strlen, strskip and toWS, which take around two third of the cycles they used to (although strskip has more overhead). 10 bytes saved total.
toWS had two bytes added inlining the isWS call, and a jump to unsetZ was inlined too, saving a byte. This saved 29 cycles, with the original function being 90 cycles. I looked at other uses of isWS and it's difficult to inline it effectively in every situation, so I haven't inlined it elsewhere.
rdWS had a byte and two cycles saved by inlining a jump to unsetZ.
strskip is the same size, with the loop cut down from 35 cycles to 21 cycles, but 18 cycles are added outside the loop. I expect one character strings are in the minority, so this should save cycles overall.
strlen had 8 bytes saved, with the loop cut down from 38 cycles to 21 cycles, and 18 cycles removed outside the loop.
* Fixed strskip
Strskip wasn't preserving a properly. The new code uses the shadow af register, so whilst a byte and 4 cycles have been added outside the loop, it's safer and cleaner. The flags register isn't affected, but since the search goes for up to 64Kb I think it's safe to say the end of the string will always be reached.
* Remove inlining of isWS
