We don't need to generate captures and non
captures in a separate step. This gives another
7% push to perft speed.
yes, I know, it is totally useless :-)
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is now no more needed to know dc candidates
inside MovePicker, so avoid calculating there.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Big cleanup and semplification of pawns evasions that
now are pseudo-legal as the remaining moves. This
allow us to remove a lot of tricky code.
Verified against perft: no functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Remove a bunch of difficult and tricky code to test
legality of castle and ep moves and instead use a slower
but simpler check against the list of generated legal moves.
Because these moves are very rare the performance impact
is small but code semplification is ver big: almost 100 lines
of difficult code removed !
No functionality change. No performance change (strangely enough
there is no even minimal performance regression in pgo builds but
instead a slightly and unexpected increase).
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This avoids calculating the array entry position
at each access and gives another boost of almost 1%.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
previous used move_is_legal to verify that the move from the TT
was legal, and the old version of move_is_legal only works when
the side to move is not in check. Fixed this by adding a separate,
slower version of move_is_legal which works even when the side to
move is in check.
Instead of loop across all legal moves to find a mate
loop across possible check moves only.
This reduces more then 10 times the number of moves to
check for a possible mate.
Also rename generate_checks() in generate_non_capture_checks()
so to better clarify what the function does.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is slower the previous uglier but faster code.
So completely restore old one for now :-(
Just leave in the rework of status backup/restore in do_move().
We will cherry pick bits of previous work once we are sure
we have fixed the performance regression.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
