They are both 64 bits unsigned integer, but it
is correct to use the proper type.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is a more standard naming (see chessprogramming wiki)
and is more stick to what table is and not what is used for.
Code in pawns.cpp is a bit more readable now, at least for me ;-)
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Pass the color for which the square is to be
considered weak, not the opposite.
It is more natural and intuitive in this way.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Absolutely no useful at all, just code obfuscation so
use real definition instead.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This is the world's fussiest compiler with +w1
Warnings reported by Richard Lloyd.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Array castleRightsMask[] is not static because it can
be different for different positions, so let it be
a Position member data. This allows to remove tricky
hacks to take in account that although it was defined
static it could change.
Theoretically now copying a position is a bit slower because
we need to copy also an array of 64 integers, but because in
split() we don't copy the position anymore, but just keep the
pointer, the added burden is not mesurable even in MP case.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It will be used by future patches and also rearranges some
half cooked code that mistakenly ended up in master in the
past.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
A pointer is enough because after a split point has been
setup master and slaves thread end up calling sp_search() or
sp_search_pv() and here a full copy of split point position is
done again, note that even master does another copy (of itself)
and this is done before any do_move() call so that master Position
is never updated between split() and sp_search().
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Renamed a bit the functions to be more clear what
we actually are doing when we craete a Position object
and explained how StateInfo works.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Game phase is a strictly function of the material
combination so its natural place is MaterialInfo,
not position.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
When false (common case) we avoid to update checkers
bitboard that although not so costly slows down a bit
this very hot and critical path.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It will be overwritten anyway.
Also other little small touches that seem to increase
speed more then the whole enum Score patch series :-(
Optimization is really a black art.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Instead of MgPieceSquareTable[16][64] and EgPieceSquareTable[16][64]
This allows to fetch mg and eg values from adjacent words in memory.
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>
Don't seem to help, perhaps because we
return an approximate SEE score instead of the
real negative score so that we have some bad capture
or evasion sub-optimal ordering that compensates
the speed up.
Anyhow after 999 games at 1+0
Mod vs Orig +240 =514 -245 -2 ELO
So almost no harm to remove and make the code simpler.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This patch cuts 30% of SEE calculations, as a drawback
a returned negative value is no more always correct if
a shortcut is found.
This could impact move order when based on negative see
score as example bad captures and evasions.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Small code cleanup and a bit faster too.
The only functional change is that in extension
in pv node we extend promotions and not only captures
when condition met.
This is practically an undetectable change and has
no impact on strenght.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is not equivalent because the check for the
50 moves rule get badly affected.
// Draw by the 50 moves rule?
if (st->rule50 > 100 || (st->rule50 == 100 && !is_check()))
return true;
So we _really_ need two counters.
Thanks to Joona and Tord to be patience with a silly guy ;-)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Null moves can artificially create a repetition
draw where instead there is no one.
So use a second counter to reset history after
a null move.
Idea from Joona.
After 999 games at 1+0
Mod vs Orig +238 =553 -208 51.50% 514.5/999 +10 ELO
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This patch make the piece list always terminated by SQ_NONE,
so that we can use a simpler and faster loop in move
generation.
Speedup is about 0.6%.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
With this very simple patch we get a speed boost
of 0.8% on my PC !
Sometime we find the most complex tricks to increase speed
when instead the best results come from the simplest solutions.
No functional change of course ;-)
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is in line with attackers_to() and is shorter and
piece is already redundant because is passed as template
parameter anyway.
Integrate also pawn_attacks_from() in the attacks_from()
family so to have an uniform attack info API.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use the definition in the few places where is needed.
As a nice side effect there is also an optimization in
generate_evasions() where the bitboard of enemy pieces
is computed only once and out of a tight loop.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is a bit longer but much easier to understand especially
for people new to the sources. I remember it was not trivial
for me to understand the returned attack bitboard refers to
attacks launched from the given square and not attacking the
given square.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Most of them are not required to be public and are
used in one place only so remove them and use its
definitions.
Also rename piece_attacks_square() in piece_attacks()
to be aligned to the current naming policy.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
These functions return bitboard of attacking pieces,
not the attacks themselfs so reflect this in the name.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Instead of pawn_attacks(Color c, Square s) define as
pawn_attacks(Square s, Color c) to be more aligned to
the others attack info functions.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Remove undefined functions sliding_attacks() and ray_attacks()
and retire square_is_attacked(), use the corresponding definition
instead. It is more clear that we are computing full attack
info for the given square.
Alos fix some obsolete comments in move generation functions.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Return the bitboard with the pawn attacks for both colors
so to be aligned to the meaning of the others piece_attacks<Piece>
templates.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This patch is built on Tord idea to use functions instead of
templates to access position's bitboards. This has the added advantage
that we don't need fallback functions for cases where the piece
type or the color is a variable and not a constant.
Also added Joona suggestion to workaround request for two types
of pieces like bishop_and_queens() and rook_and_queens().
No functionality or performance change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Use a single template to get bitboard representation of
the position given the type of piece as a constant.
This removes almost 80 lines of code and introduces an
uniform notation to be used for querying for piece type.
No functional change and no performance change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is used mainly in a bunch of inline oneliners
just below its definition. So substitute it with
the explicit definition and avoid information hiding.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Explicitly write the conditions for pawn to 7th
and passed pawn instead of wrapping in redundant
helpers.
Also retire the now unused move_is_pawn_push_to_7th()
and the never used move_was_passed_pawn_push() and
move_is_deep_pawn_push()
Function extension() is so time critical that this
simple patch speeds up the pgo compile of 0.5% and
it is also more clear what actually happens there.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
