Speed up perft

[stockfish] / Readme.txt

diff --git a/Readme.txt b/Readme.txt
index 0c6f5c7210bec5e62f17f3a12d40e77c78673151..09216abc21a8b80bf6d1e1ad91214937e8aab905 100644 (file)
--- a/Readme.txt
+++ b/Readme.txt
@@ -14,7 +14,9 @@ number of CPUs on your computer and set the number of search threads
 accordingly, but please be aware that the detection is not always\r
 correct.  It is therefore recommended to inspect the value of the\r
 "Threads" UCI parameter, and to make sure it equals the number of CPU\r
-cores on your computer.\r
+cores on your computer. If you are using more than four threads, it
+is recommended to raise the value of "Minimum Split Depth" UCI parameter
+to 6.
 \r
 \r
 2. Files\r
@@ -54,6 +56,15 @@ The exception is computer with big-endian CPUs, like PowerPC
 Macintoshes. Some of the bitboard routines in the current version of\r
 Stockfish are endianness-sensitive, and won't work on a big-endian CPU.\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
 ---------------\r