Considered adding --ignore-errors to watch.py, but it doesn't really
make sense with watch.py's implementation. watch.py would need to not update
in realtime, which conflicts with other use cases.
It's quite lucky a spare bit is free in the tag encoding, this means we
don't need a reserved length value as originally planned. We end up using
all of the bits that overlap the alt pointer encoding, which is nice and
unexpected.
It turns out statefulness works quite well with this algorithm (The
prototype was in Haskell, which created some artificial problems. I
think it may have just been too high-level a language for this
near-instruction-level algorithm).
This bias makes it so that tag lookups always find a tag strictly >= the
requested tag, unless we are at the end of the tree.
This makes tree traversal trivial, which is quite nice.
Need to remove ntag now, it's no longer needed.
- Moved alt encoding 0x1 => 0x4, which can lead to slightly better
lookup tables, the perturb bit takes the same place as the color bit,
which means both can be ignored in readonly operations.
- Dropped lfs_rbyd_fetchmatch, asking each lfs_rbyd_fetch to include NULL
isn't that bad.
New encoding:
tags:
iiii iiiiiii iiiiiTT TTTTTTt ttt0tpv
^--------^------^^^- 16-bit id
'------|||- 8-bit type2
'||- 5-bit type1
'|- perturb bit
'- valid bit
llll lllllll lllllll lllllll lllllll
^- n-bit length
alts:
wwww wwwwwww wwwwwww wwwwwww www1dcv
^^^-^- 28-bit weight
'|-|- color bit
'-|- direction bit
'- valid bit
jjjj jjjjjjj jjjjjjj jjjjjjj jjjjjjj
^- n-bit jump
Christopher Haster