Author: Nicolas Carrasco
Date: 09:57:08 12/20/99
Dear Guys,
While I started studying how to write a Bitboard chess engine I read “Galahad
Chess Engine” move generator from James F. Swafford publicated on:
http://members.xoom.com/jswaff/chessprg/ at Move Generation section.
NOTE: At the end you will have a link to download the move-gen.
I wrote him several e-mails but never recived a reply.
To generate the EP captures he does this that I think is wrong because he forget
a position with two possible EP captures.
if (posptr->epsquare<64) {
to_map=bpmoves[posptr->epsquare]&posptr->whitepawns;
if (to_map) {
from_sq=LSB(to_map);
m->m.b.from=from_sq;
m->m.b.to=posptr->epsquare;
m->m.b.promote=0;
m->m.b.bits=21;
m->score=0;
m++;
}
}
And nothing else for EP captures.
I think the correct way is:
if (posptr->epsquare<64) {
to_map=bpmoves[posptr->epsquare]&posptr->whitepawns;
while (to_map) {
from_sq=LSB(to_map);
to_map^=mask[to_sq];
m->m.b.from=from_sq;
m->m.b.to=posptr->epsquare;
m->m.b.promote=0;
m->m.b.bits=21;
m->score=0;
m++;
}
}
Or:
if (posptr->epsquare<64) {
to_map=bpmoves[posptr->epsquare]&posptr->whitepawns;
if (to_map) {
from_sq=LSB(to_map);
to_map^=mask[to_sq];
m->m.b.from=from_sq;
m->m.b.to=posptr->epsquare;
m->m.b.promote=0;
m->m.b.bits=21;
m->score=0;
m++;
if (to_map) {
from_sq=LSB(to_map);
m->m.b.from=from_sq;
m->m.b.to=posptr->epsquare;
m->m.b.promote=0;
m->m.b.bits=21;
m->score=0;
m++;
}
}
}
To James: Can you tell me your usual e-mail address?
Thanks in advance and good luck.
This page took 0.01 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.