We don't backup anymore but use the renamed StateInfo
argument passed in do_move() to store the new position
state when doing a move.
Backup is now just revert to previous StateInfo that we know
because we store a pointer to it.
Note that now backing store is up to the caller, Position is
stateless in that regard, state is accessed through a pointer.
This patch will let us remove all the backup/restore copying,
just a pointer switch is now necessary.
Note that do_null_move() still uses StateInfo as backup.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We store it now in the same UndoInfo struct as 'previous'
field, so when doing a move we also know where to get
the previous info when undoing the back the move.
This is needed for future patches and is a nice cleanup anyway.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Also templetize compute_value() can be simpler now that
the above is templetized too.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This nice union trick let us optimize the speed and
remove the now unuseful backup() and restore() functions.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
After have been calculated cache their values
so to avoid another expensive call to hidden_checks()
if pinned_pieces() or discovered_check_candidates() are
called with the same position.
Add also interface to get pinners bitboard, we already have
this value so save it instead of discard.
Now that, after the first call to pinned_pieces() the following
are very cheap we can rewrite and cleanup all the checking handling.
So this patch is a prerequisite for future work.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
They hide the underlying uniform function call with
no benefit.
A little bit more verbose but now is clear what happens.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Pass value as an argument instead or recalculating it.
Altough call is cheap this is a very hot path so with
this patch total time spent for move_is_capture() is almost
halved.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Currently fails if we test with a move that is not of
from the side to move but from the opponent.
This is the typical case of the threat from null move
search. The result is an erroneus prune of the defending
moves, see PruneDefendingMoves in ok_to_prune()
Fix the test to work also with threat moves.
Bug was always in but was unhidden by a patch of 17/12/2008
"Trigger of PawnEndgameExtension if capture is not a pawn"
Until then it was hidden by a tricky check in the prune
conditions instead of the natural move_is_capture()
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use Position::compute_material_key() to do the job,
so we are sure there is not key mismatch during
endgame function lookups.
This fixes two endgames hash errors that caused two
endgames to be disabled.
This patch is also a code cleanup because removes a lot
of messy key assignments.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Also integrate scaling and evaluation in a
single base class.
Nice use of templates here :-)
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
In generate_piece_moves() to be more uniform with other
functions. Unfortunatly the different number of calling arguments
do not allow us to easily integrate in generate_piece_moves()
template family.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Small code tidy up and a little optimization
to avoid calling generate_piece_blocking_evasions()
when blockSquares is empty (30% of cases).
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Now that we have removed sliders checkers attacks
from evasion's set we can simplyfy legality check.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Rewrite as in generate_piece_moves() using a for
loop instead of the slower serializing of the
bitboard with pop_1st_bit()
This will allow also to merge with generate_piece_moves()
when we will drop legality constrain on generate_evasions()
Generated moves are not changed, but are generated in a
different order, this changes the number of nodes at fixed
depth test.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Discovery check candidates are normally empty, so
avoid discovery checks generation in that common case.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Find squares attacked by slider checkers, we will
remove them from king evasions set so to avoid a couple
of cycles in the slow king evasions legality check loop.
Not a biggie, but now generate_evasions() is faster then
generate_non_captures(), before was slower.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
