This Fhourstones implementation (software) is copyright (c) 1992 by John Tromp (firstname.lastname@example.org).
On 22 Jul 1993 John Tromp sent me Fhourstones 1.0. A new option is provided ('-DMOD64' for 64-bit machines) and there are some print out changes. The results are now reported to a precision of one digit to the right of the decimal point in the KPos/sec output. I changed the old table of results to reflect this change as well. Fhourstones 1.0 and previous results should be the same ...
The Fhourstones benchmark (c4 for short) solves positions in connect-4, the well-known game played on a vertical board of 7 columns by 6 rows, where 2 players take turns in dropping 'stones' in a column. The first player to get 4 stones in a horizontal, vertical, or diagonal row, wins the game. The game is drawn if there is no winner after 42 moves.
Some technical notes: Of the full 49 bit lock that describes a connect-4 position, only 32 bits are stored in the hashtable entry while the remaining 17 are subsumed in the hash-address. To also accomodate 8 fold probing, a minimum of one million hash table entries are required. The benchmark uses just over 5 MBytes of memory. The potentially expensive modulo operations are implemented with repeated table look-up. The use of small integer sizes is available as an option ('-DSMALL' default). Although this benchmark emphasizes random access performance, it also exercises standard scalar performance; the recursive alpha-beta calls, incremental threat table computations, history table updates, and move-reordering represent a fair mix of scalar operations. Fhourstones is a pure 'integer benchmark'.
The Fhourstones program (c4.shar and c4.doc) and latest results (c4.tbl, this table) can be obtained via anonymous ftp from 'ftp.nosc.mil' in directory 'pub/aburto'. The ftp.nosc.mil IP address is: 188.8.131.52
Please send new results (new machines, compilers, compiler options) to: email@example.com. I will keep the results up-dated and post periodically to 'comp.benchmarks'. Any comments are greatly appreciated too.
Results as of 05 Nov 1996: