Make engine ONE_PLY value independent

This non-functional change patch is a deep work to allow SF to be independent
from the actual value of ONE_PLY (currently set to 1). I have verified SF is
now independent for ONE_PLY values 1, 2, 4, 8, 16, 32 and 256.

This patch gives consistency to search code and enables future work, opening
the door to safely tweaking the ONE_PLY value for any reason.

Verified for no speed regression at STC:
LLR: 2.95 (-2.94,2.94) [-3.00,1.00]
Total: 95643 W: 17728 L: 17737 D: 60178

No functional change.
This commit is contained in:
Marco Costalba
2016-08-19 12:17:38 +02:00
parent 133808851d
commit 4c5cbb1b14
4 changed files with 45 additions and 36 deletions

View File

@@ -92,8 +92,8 @@ TTEntry* TranspositionTable::probe(const Key key, bool& found) const {
// nature we add 259 (256 is the modulus plus 3 to keep the lowest
// two bound bits from affecting the result) to calculate the entry
// age correctly even after generation8 overflows into the next cycle.
if ( replace->depth8 - ((259 + generation8 - replace->genBound8) & 0xFC) * 2 * ONE_PLY
> tte[i].depth8 - ((259 + generation8 - tte[i].genBound8) & 0xFC) * 2 * ONE_PLY)
if ( replace->depth8 - ((259 + generation8 - replace->genBound8) & 0xFC) * 2
> tte[i].depth8 - ((259 + generation8 - tte[i].genBound8) & 0xFC) * 2)
replace = &tte[i];
return found = false, replace;