X-Git-Url: https://git.sesse.net/?p=stockfish;a=blobdiff_plain;f=Readme.txt;h=1a3713985e7cec3e47746503892284cd518f4c64;hp=0c6f5c7210bec5e62f17f3a12d40e77c78673151;hb=72ab2cd3e98e694ef22316153a42462e2484b466;hpb=063e2441b17b8260de443b3d580f49b3d65d03c7

diff --git a/Readme.txt b/Readme.txt
index 0c6f5c72..1a371398 100644
--- a/Readme.txt
+++ b/Readme.txt
@@ -54,6 +54,15 @@ The exception is computer with big-endian CPUs, like PowerPC
 Macintoshes. Some of the bitboard routines in the current version of
 Stockfish are endianness-sensitive, and won't work on a big-endian CPU.
 
+Stockfish has POPCNT instruction runtime detection and support. This can
+give an extra speed on Core i7 or similar systems. To enable this feature
+(disabled by default) simply uncomment #define USE_POPCNT in bitcount.h
+before to compile.
+
+On 64 bit Unix-like systems the 'bsfq' assembly instruction will be used
+for bit counting. Detection is automatic at compile time, but in case you
+experience compile problems you can comment out #define USE_BSFQ line in types.h
+
 
 5. Terms of use
 ---------------