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Because of the inner six bit mask with 01111110b, which would usually require an additional shift right 1 for a 0..63 range, is already implicitly multiplied by two (0,2,4,....126). With a two-dimensional array it takes one additional instruction ;-) BYTE arrFirstRankAttacks64x8[64][8]; // 512 Bytes...

BYTE arrFirstRankAttacks64x8[64*8]; // 512 Bytes = 1/2KByte U64 rankAttacks(U64 occ, enumSquare sq) { unsigned int file = sq & 7; unsigned int rkx8 = sq & 56; // rank * 8 occ = (occ >> rkx8) & 2*63; U64 attacks = arrFirstRankAttacks64x8[4*occ + file]; return attacks << rkx8; } What I am still not c...

Hi, What is LMP and how does it work/is it implemented? LMP, late move pruning not reduction. I see mentions of it here and there but it is not described on the wiki. Mentioned on the Futility Pruning page as Move Count Based Pruning aka Late Move Pruning (LMP) with reference post by Tom King.

You are right. The routine should exclude rams: U64 wBackward(U64 wpawns, U64 bpawns) { U64 stops = (wpawns << 8) & ~bpawns; U64 wAttackSpans = wEastAttackFrontSpans(wpawns) | wWestAttackFrontSpans(wpawns); U64 bAttacks = bPawnEastAttacks(bpawns) | bPawnWestAttacks(bpawns); return (stops & bAttacks...

You strictly are right. The routine may exclude rams (or even stops not occupied by any pawn): U64 wBackward(U64 wpawns, U64 bpawns) { U64 stops = (wpawns << 8) & ~bpawns; U64 wAttackSpans = wEastAttackFrontSpans(wpawns) | wWestAttackFrontSpans(wpawns); U64 bAttacks = bPawnEastAttacks(bpawns) | bPaw...

My condolences to his wife and family as well. RIP Cock de Gorter and thank you for organizing the Aegon tournaments.

Gerd Isenberg

I never seen [4] (but started some attempts to obtain the scan of this article) <...> 4. Sсhliebs G. (1953). Über die Gründzuge eines Programms für eine Schachspielende Rechenmaschine / Funk und Ton, 1953, vol. 7, pp. 257—265. Hooray!! Here is the paper: https://yadi.sk/d/my7VqYaYaaLc1w And it look...

In order not to create a separate topic for the sake of one message, I will write here. There is an interesting article by David Levy "Alan Turing on Computer Chess" from S. Barry Cooper, J. van Leeuwen "Alan Turing: His Work and Impact" about Turing's "paper machine": googlebooks Thanks! I missed ...

The most intriguing part from my point of view is "his flagging interest in mathematics revived by a kind woman who had known his father, a well-known European mathematician". Who was his father?.. Benjamin Abram Bernstein [https://en.wikipedia.org/wiki/Benjamin_Abram_Bernstein]? Felix Bernstein [h...

Finally I've got some progress! :) McCorduck, P. (2004). Machines who think: a personal inquiry into the history and prospects of artificial intelligence (2. Edition). London: A.K. Peters. // https://books.google.ru/books?id=aH9QAAAAMAAJ Great finding! Pamela McCorduck was married to Joseph F. Trau...