-Ensuring that the line with #define USE_32BIT_ATTACKS" near the top\r
-of bitboard.h is commented out should solve this problem.\r
-Commenting out the line with "#define USE_32BIT_ATTACKS" near the\r
-\r
-There is also a problem with compiling Stockfish on certain 64-bit\r
-systems, regardless of the endianness. If Stockfish segfaults\r
-immediately after startup, try to comment out the line with\r
-"#define USE_FOLDED_BITSCAN" near the beginning of bitboard.h and\r
-recompile.\r
-\r
-Finally, even if Stockfish does work without any changes on your\r
-computer, it might be possible to improve the performance by changing\r
-some of the #define directives in bitboard.h. The default settings\r
-are optimized for 64-bit CPUs. On 32-bit CPUs, it is probably better\r
-to switch on USE_32BIT_ATTACKS, and to use BITCOUNT_SWAR_32 instead of\r
-BITCOUNT_SWAR_64. For computers with very little memory (like\r
-handheld devices), it is possible to conserve memory by defining\r
-USE_COMPACT_ROOK_ATTACKS.\r
-\r
-\r
-6. Terms of use\r
+\r
+Stockfish has POPCNT instruction runtime detection and support. This can\r
+give an extra speed on Core i7 or similar systems. To enable this feature\r
+(disabled by default) simply uncomment #define USE_POPCNT in bitcount.h\r
+before to compile.\r
+\r
+On 64 bit Unix-like systems the 'bsfq' assembly instruction will be used\r
+for bit counting. Detection is automatic at compile time, but in case you\r
+experience compile problems you can comment out #define USE_BSFQ line in types.h\r
+\r
+\r
+5. Terms of use\r