It seems more accurate: lsb is clear while 'first
bit' depends from where you look at the bitboard.
And fix compile in case of 64 bits platforms that
do not use BSFQ intrinsics.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is more correct given what the function does. In
particular single_bit() returns true also in case of
empty bitboards.
Of course also the usual renaming while there :-)
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
With this change sources are fully endianess
independent, so we can simplify the Makefile.
Somewhat surprisingly we don't have any speed
regression !
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Incredible typo from my side!
The 2 tables are completely different, one counts 1s the
other returns the msb position. Even more incredible
the 'stockfish bench' command returns the same number
of nodes!!!
Spotted by Justin Blanchard.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Replace a 64 bit 'and' by two 32 bits ones and
use unsigned instead of int.
This simple patch increases perft speed of 6% on
my Intel Core 2 Duo !
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
This allows to retire ClearMaskBB[] and use just
one SquareBB[] array to set and clear a bit.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
All the piece dependant data is passed now as
function arguments so that the code is exactly
the same for bishop and rook.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It is more correct and specific. Another naming
improvement while reading Critter sources.
No functional changes.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
On that platform non-bracketed casting are not supported.
Reported by Richard Lloyd.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Now that HasPopCnt is a compile time constant we can
centralize and unify the BitCountType selection.
Also rename count_1s() in the more standard popcount()
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
It was meant to build a single binary optimized
for any kind of CPU: with and without hardware POPCNT.
This is a nice idea but in practice was never used, or
people builds binary with popcnt enabled or not, mainly
according to their type of CPU. And it was also never
used in the official Jim's builds where, in case, would
be easier for a number of reasons, do build two different
versions: with and without SEE42 support.
So retire this feature and simplify the code.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Add comments and rename stuff to better clarify what the
magic bitboard initialization code does.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Easy, almost trivial simplification, I don't understand
how I missed this before !!
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We should start from i = 0, it works by accident because
static storage BSFTable[] is init to zero by default.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Allow to choose among 4096 instances of pseudo-random
sequences instead of the previous 64 so the probability
to find a better sequence increases and actually we have
a much better 64 bit case and we can also use the 64 bit
version of pick_magic() also for 32 bits and althoug sub
optimal, because now we can have more choices results are
even slightly better also for 32 bit.
Use also a faster submask().
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Good result for 32 bit case where computation is very fast,
still not satisfying on 64 bit case where the magics seem
a bit harder to get.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Due to a -2% speed penalty. This patch takes the best
of the previous series without the regression due to
introduction of Magic struct.
Speedup against previous revision is of almost 3% !!!!
No functional change both in 32 and 64 bits.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
We can calculate them counting the masks bits.
Also small tweak to sliding_attacks()
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
With off-by-one bug in InFrontBB[] loop fixed.
Also use int instead of File to workaround a bug
in mingw 4.4.0 in first loop that cycles forever.
No functional change.
Signed-off-by: Marco Costalba <mcostalba@gmail.com>
Marco Costalba