Big-endian compatible pop_1st_bit()
Thanks to Eric Mullins we have now endian friendly pop_1st_bit() and also is removed the need to use -fno-strict-aliasing compiler option with GCC. Speed is almost as fast, very small difference if any in perft test, so I assume almost no difference in real games. No functional change. Signed-off-by: Marco Costalba <mcostalba@gmail.com>sf_2.3.1_base
Marco Costalba
parent
a9e536a7eb
commit
dc286d2673
176
Readme.txt
176
Readme.txt
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@ -1,91 +1,91 @@
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1. Introduction
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---------------
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Stockfish is a free UCI chess engine derived from Glaurung 2.1. It is
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not a complete chess program, but requires some UCI compatible GUI
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(like XBoard with PolyGlot, eboard, Jos<6F>, Arena, Sigma Chess, Shredder,
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Chess Partner, or Fritz) in order to be used comfortably. Read the
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documentation for your GUI of choice for information about how to use
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Stockfish with your GUI.
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This version of Stockfish supports up to 8 CPUs, but has not been
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tested thoroughly with more than 2. The program tries to detect the
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number of CPUs on your computer and set the number of search threads
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accordingly, but please be aware that the detection is not always
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correct. It is therefore recommended to inspect the value of the
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"Threads" UCI parameter, and to make sure it equals the number of CPU
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1. Introduction
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---------------
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Stockfish is a free UCI chess engine derived from Glaurung 2.1. It is
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not a complete chess program, but requires some UCI compatible GUI
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(like XBoard with PolyGlot, eboard, Jos<6F>, Arena, Sigma Chess, Shredder,
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Chess Partner, or Fritz) in order to be used comfortably. Read the
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documentation for your GUI of choice for information about how to use
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Stockfish with your GUI.
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This version of Stockfish supports up to 8 CPUs, but has not been
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tested thoroughly with more than 2. The program tries to detect the
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number of CPUs on your computer and set the number of search threads
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accordingly, but please be aware that the detection is not always
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correct. It is therefore recommended to inspect the value of the
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"Threads" UCI parameter, and to make sure it equals the number of CPU
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cores on your computer. If you are using more than four threads, it
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is recommended to raise the value of "Minimum Split Depth" UCI parameter
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to 6.
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2. Files
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--------
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This distribution of Stockfish consists of the following files:
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* Readme.txt, the file you are currently reading.
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* Copying.txt, a text file containing the GNU General Public
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License.
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* src/, a subdirectory containing the full source code, including a
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Makefile that can be used to compile Stockfish on Unix-like
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systems. For further information about how to compile Stockfish
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yourself, read section 4 below.
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* polyglot.ini, for using Stockfish with Fabien Letouzey's PolyGlot
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adapter.
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3. Opening books
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----------------
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This version of Stockfish has experimental support for PolyGlot opening
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books. For information about how to create such books, consult the
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PolyGlot documentation. The book file can be selected by setting the
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UCI parameter "Book File".
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4. Compiling it yourself
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------------------------
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On Unix-like systems, it should usually be possible to compile
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Stockfish directly from the source code with the included Makefile.
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The exception is computer with big-endian CPUs, like PowerPC
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Macintoshes. Some of the bitboard routines in the current version of
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Stockfish are endianness-sensitive, and won't work on a big-endian CPU.
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Stockfish has POPCNT instruction runtime detection and support. This can
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give an extra speed on Core i7 or similar systems. To enable this feature
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(disabled by default) simply uncomment #define USE_POPCNT in bitcount.h
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before to compile.
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On 64 bit Unix-like systems the 'bsfq' assembly instruction will be used
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for bit counting. Detection is automatic at compile time, but in case you
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experience compile problems you can comment out #define USE_BSFQ line in types.h
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5. Terms of use
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---------------
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Stockfish is free, and distributed under the GNU General Public License
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(GPL). Essentially, this means that you are free to do almost exactly
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what you want with the program, including distributing it among your
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friends, making it available for download from your web site, selling
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it (either by itself or as part of some bigger software package), or
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using it as the starting point for a software project of your own.
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The only real limitation is that whenever you distribute Stockfish in
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some way, you must always include the full source code, or a pointer
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to where the source code can be found. If you make any changes to the
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source code, these changes must also be made available under the GPL.
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For full details, read the copy of the GPL found in the file named
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Copying.txt.
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6. Feedback
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-----------
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The author's e-mail address is mcostalba@gmail.com
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2. Files
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--------
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This distribution of Stockfish consists of the following files:
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* Readme.txt, the file you are currently reading.
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* Copying.txt, a text file containing the GNU General Public
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License.
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* src/, a subdirectory containing the full source code, including a
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Makefile that can be used to compile Stockfish on Unix-like
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systems. For further information about how to compile Stockfish
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yourself, read section 4 below.
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* polyglot.ini, for using Stockfish with Fabien Letouzey's PolyGlot
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adapter.
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3. Opening books
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----------------
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This version of Stockfish has experimental support for PolyGlot opening
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books. For information about how to create such books, consult the
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PolyGlot documentation. The book file can be selected by setting the
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UCI parameter "Book File".
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4. Compiling it yourself
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------------------------
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On Unix-like systems, it should usually be possible to compile
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Stockfish directly from the source code with the included Makefile.
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For big-endian machines like Power PC you need to enable the proper
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flag changing from -DNBIGENDIAN to -DBIGENDIAN in the Makefile.
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Stockfish has POPCNT instruction runtime detection and support. This can
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give an extra speed on Core i7 or similar systems. To enable this feature
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(disabled by default) simply uncomment #define USE_POPCNT in bitcount.h
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before to compile.
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On 64 bit Unix-like systems the 'bsfq' assembly instruction will be used
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for bit counting. Detection is automatic at compile time, but in case you
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experience compile problems you can comment out #define USE_BSFQ line in types.h
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5. Terms of use
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---------------
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Stockfish is free, and distributed under the GNU General Public License
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(GPL). Essentially, this means that you are free to do almost exactly
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what you want with the program, including distributing it among your
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friends, making it available for download from your web site, selling
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it (either by itself or as part of some bigger software package), or
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using it as the starting point for a software project of your own.
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The only real limitation is that whenever you distribute Stockfish in
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some way, you must always include the full source code, or a pointer
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to where the source code can be found. If you make any changes to the
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source code, these changes must also be made available under the GPL.
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For full details, read the copy of the GPL found in the file named
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Copying.txt.
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6. Feedback
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-----------
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The author's e-mail address is mcostalba@gmail.com
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14
src/Makefile
14
src/Makefile
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@ -39,6 +39,14 @@ ICCFLAGS += -DNDEBUG
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ICCFLAGS-OSX += -DNDEBUG
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### ==========================================================================
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### Enable/disable compile for a big-endian CPU, disabled by default
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### ==========================================================================
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GCCFLAGS += -DNBIGENDIAN
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ICCFLAGS += -DNBIGENDIAN
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ICCFLAGS-OSX += -DNBIGENDIAN
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### ==========================================================================
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### Run built-in benchmark for pgo-builds with: 32MB hash 1 thread 10 depth
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### These settings are generally fast, but may be changed experimentally
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@ -47,9 +55,9 @@ PGOBENCH = ./$(EXE) bench 32 1 10 default depth
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### General compiler settings. Do not change
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GCCFLAGS += -g -Wall -fno-exceptions -fno-rtti -fno-strict-aliasing
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ICCFLAGS += -g -Wall -fno-exceptions -fno-rtti -fno-strict-aliasing -wd383,869,981,10187,10188,11505,11503
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ICCFLAGS-OSX += -g -Wall -fno-exceptions -fno-rtti -fno-strict-aliasing -wd383,869,981,10187,10188,11505,11503
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GCCFLAGS += -g -Wall -fno-exceptions -fno-rtti
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ICCFLAGS += -g -Wall -fno-exceptions -fno-rtti -wd383,869,981,10187,10188,11505,11503
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ICCFLAGS-OSX += -g -Wall -fno-exceptions -fno-rtti -wd383,869,981,10187,10188,11505,11503
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### General linker settings. Do not change
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@ -317,8 +317,8 @@ Square pop_1st_bit(Bitboard* b) {
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#elif !defined(USE_BSFQ)
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CACHE_LINE_ALIGNMENT
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static const int BitTable[64] = {
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static CACHE_LINE_ALIGNMENT
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const int BitTable[64] = {
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63, 30, 3, 32, 25, 41, 22, 33, 15, 50, 42, 13, 11, 53, 19, 34, 61, 29, 2,
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51, 21, 43, 45, 10, 18, 47, 1, 54, 9, 57, 0, 35, 62, 31, 40, 4, 49, 5, 52,
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26, 60, 6, 23, 44, 46, 27, 56, 16, 7, 39, 48, 24, 59, 14, 12, 55, 38, 28,
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@ -336,26 +336,34 @@ union b_union {
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Bitboard b;
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struct {
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#if defined (BIGENDIAN)
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uint32_t h;
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uint32_t l;
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#else
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uint32_t l;
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uint32_t h;
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#endif
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} dw;
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};
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// WARNING: Needs -fno-strict-aliasing compiler option
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Square pop_1st_bit(Bitboard* bb) {
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b_union u;
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b_union u;
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Square ret;
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u.b = *bb;
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u.b = *bb;
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if (u.dw.l)
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{
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*((uint32_t*)bb) = u.dw.l & (u.dw.l - 1);
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return Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]);
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}
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*((uint32_t*)bb+1) = u.dw.h & (u.dw.h - 1); // Little endian only?
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return Square(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]);
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if (u.dw.l)
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{
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ret = Square(BitTable[((u.dw.l ^ (u.dw.l - 1)) * 0x783a9b23) >> 26]);
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u.dw.l &= (u.dw.l - 1);
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*bb = u.b;
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return ret;
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}
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ret = Square(BitTable[((~(u.dw.h ^ (u.dw.h - 1))) * 0x783a9b23) >> 26]);
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u.dw.h &= (u.dw.h - 1);
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*bb = u.b;
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return ret;
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}
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#endif
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