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Subject: Re: A faster move generator than previously known

Author: Robert Hyatt

Date: 21:02:16 08/08/03

Go up one level in this thread


On August 08, 2003 at 08:31:38, Vincent Diepeveen wrote:

>On August 08, 2003 at 08:23:04, Sune Fischer wrote:
>
>>On August 08, 2003 at 07:42:06, Vincent Diepeveen wrote:
>>
>>>On August 08, 2003 at 06:47:34, Sune Fischer wrote:
>>>
>>>You miss the point completely Sune.
>>
>>Do you have a point?
>>
>>>I can completely branchless (only with a loop which as you might know hardly
>>>generates branch mispredictions) generate semi legal moves with this also using
>>>less RAM using general code.
>>
>>When you run it 10 mill times in a tight loop I would not expect many brach
>>mispridictions.
>>Another reason why the test is flawed.
>
>you show another time you know nothing from how processors branch prediction
>works. There is a lot of different processors out there and it just doesn't work
>like *that*.

You should first study how the PIV predicts branches _yourself_.

I don't believe you understand it at all...


>
>If you generate for say 16 pieces like 16 bitboards and try to get bits out of
>'em with that code in crafty that uses branches then you will realize probably
>also that at non-itanium processors you will get branch mispredictions.
>
>It doesn't take away that the real beauty of my generator is trivially not made
>for 10 million times in a row stuff.
>
>Small cache usage (depending whether you put it in 'chars' or in 'ints') in
>combination with just loops in evaluation for each piece. No hard predictions to
>make.
>
>>>So that kicks the hell out of anything you got over there.
>>
>>I have things that kick the hell out of anything you can do, so what?
>>
>>Gotta look at the big picture Vince.
>>
>>-S
>>
>>>>On August 07, 2003 at 23:48:51, Vincent Diepeveen wrote:
>>>>
>>>>>You guys can figure out the rest i bet seeing this code.
>>>>>
>>>>>All that bitboard idiocy always. This kicks the hell out of it.
>>>>
>>>>I doubt it, I can with bitboards incrementally generate 59 Mn/s on my 2Gig, you
>>>>claim 73 Mn/s on 2.1Gig, but that's not incrementally I bet.
>>>>
>>>>Also, you seem to be doing Pseudo move gen, with a capital P, do you also add
>>>>moves where the king walks into a check?
>>>>This would make your silly test faster so I assume you do.
>>>>
>>>>Of course now you'll have to waste time sorting the illegal moves, not to
>>>>mention making and unmaking them.
>>>>
>>>>Try and sort the moves, feel free to do bubble sort or whatever, you'll end up
>>>>in the 20 Mn/s range.
>>>>
>>>>Btw. if I or others cared about optimizing this routine as much as you do, we'd
>>>>all be going 100+ Mn/s :)
>>>>
>>>>-S.
>>>>
>>>>>Vincent Diepeveen,
>>>>>8 august 2003  5:53 AM
>>>>>
>>>>>#if MSVC
>>>>>__inline
>>>>>#endif
>>>>>void GenMovesI(RecursionBlock *rb,int sq) {
>>>>>  int SRsq,piece,u,xside,*s,*t,side,*v,*w;
>>>>>
>>>>>  side  = rb->side;
>>>>>  xside = rb->xside;
>>>>>  SRsq  = (sq<<6);
>>>>>  piece = board[sq];
>>>>>  if( piece == pawn ) {
>>>>>    v = ipiecepos[side][sq];
>>>>>    w = ipawndir[side][sq];
>>>>>    u = *v++;
>>>>>    if( row(u) != 0 && row(u) != 7 ) {
>>>>>      if( color[u] == neutral) {
>>>>>        rb->zetend->zet = (SRsq|u);
>>>>>        rb->zetend++;
>>>>>        if( (u=*v) != 128 && color[u] == neutral ) { /* indien u == sq dan false
>>>>>*/
>>>>>          rb->zetend->zet = (SRsq|u);
>>>>>          rb->zetend++;
>>>>>        }
>>>>>      }
>>>>>
>>>>>      u = *w++;
>>>>>      if( color[u] == xside ) {/* ppos bevat geen 100, maar sq. */
>>>>>        rb->zetend->zet = (SRsq|u|move_captures);
>>>>>        rb->zetend++;
>>>>>      }
>>>>>      if( (u=*w) != 128 && color[u] == xside ) {
>>>>>        rb->zetend->zet = (SRsq|u|move_captures);
>>>>>        rb->zetend++;
>>>>>      }
>>>>>    }
>>>>>    else {
>>>>>      if( color[u] == neutral) {
>>>>>        rb->zetend->zet = (SRsq|u|move_pqueen);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_pknight);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_prook);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_pbishop);
>>>>>        rb->zetend++;
>>>>>      }
>>>>>      u = *w++;
>>>>>      if( color[u] == xside) {/* captures */
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_pqueen);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_pknight);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_prook);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_pbishop);
>>>>>        rb->zetend++;
>>>>>      }
>>>>>      if( (u=*w) != 128 && color[u] == xside) {
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_pqueen);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_pknight);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_prook);
>>>>>        rb->zetend++;
>>>>>        rb->zetend->zet = (SRsq|u|move_captures|move_pbishop);
>>>>>        rb->zetend++;
>>>>>      }
>>>>>    }
>>>>>  }
>>>>>  else {
>>>>>    t = cancapside[side];
>>>>>    if( sweep[piece] ) {
>>>>>      int *vh,*wh,uh;
>>>>>      s  = andscan[0];
>>>>>      vh = ipiecepos[piece][sq];
>>>>>      wh = iskippos[sq];
>>>>>      uh = *vh++;
>>>>>      do {
>>>>>        int p1=snelbord[uh],sh=wh[uh]; /* local variables is faster for GCC/MSVC
>>>>>*/
>>>>>        vh += (s[p1]&sh);
>>>>>        if( color[uh] != side ) {
>>>>>          rb->zetend->zet = (SRsq|uh|t[p1]);
>>>>>          rb->zetend++;
>>>>>        }
>>>>>      } while( (uh=*vh++) != 128 );
>>>>>
>>>>>      /*vi = gentable[piece-3][sq];
>>>>>      s  = doorscan[0];
>>>>>      u  = vi[sq];
>>>>>      do {
>>>>>        if( color[u] != side ) {
>>>>>          cappiece = snelbord[u];
>>>>>          rb->zetend->zet = (SRsq|u|t[cappiece]);
>>>>>          rb->zetend++;
>>>>>          u = vi[(s[cappiece]|u)];
>>>>>        }
>>>>>        else {
>>>>>          u = vi[(64|u)];
>>>>>        }
>>>>>      } while( u != 128 );*/
>>>>>    }
>>>>>    else {
>>>>>      v = ipiecepos[piece][sq];
>>>>>      u = *v++;
>>>>>      do {
>>>>>        if( color[u] != side ) {
>>>>>          rb->zetend->zet = (SRsq|u|t[snelbord[u]]);
>>>>>          rb->zetend++;
>>>>>        }
>>>>>      } while( (u=*v++) != 128 );
>>>>>    }
>>>>>  }
>>>>>}
>>>>>
>>>>>void MoveListI(RecursionBlock *rb,struct Move *CFEP) {
>>>>>/* Generate all semi-legal moves. Check is ignored.
>>>>>*/
>>>>>  int f,to,from,u,*psq,*pend,*w;
>>>>>
>>>>>  to = CFEP->zet&63;
>>>>>  rb->zetend = rb->SemiLegals;
>>>>>  if( board[to] == pawn ) { /* for enpassant */
>>>>>    from = (CFEP->zet>>6)&63;
>>>>>    if( to-from == 16 || from-to == 16 ) {
>>>>>      f = (to+from)>>1;
>>>>>      w = ipawndir[rb->xside][f];
>>>>>      u = *w++;
>>>>>      if( color[u] == rb->side && board[u] == pawn ) {
>>>>>        rb->zetend->zet = ((u<<6)|f|move_captures|move_enpassant);
>>>>>        rb->zetend++;
>>>>>      }
>>>>>      if( (u=*w) != 128 && color[u] == rb->side && board[u] == pawn ) {
>>>>>        rb->zetend->zet = ((u<<6)|f|move_captures|move_enpassant);
>>>>>        rb->zetend++;
>>>>>      }
>>>>>    }
>>>>>  }
>>>>>
>>>>>  psq  = PieceList[rb->side];
>>>>>  pend = PieceList[rb->side]+PieceMax[rb->side];
>>>>>  if( !castld[rb->side] ) {
>>>>>    u = *psq;
>>>>>    if( castle(rb->side,u,u+2) ) {
>>>>>      rb->zetend->zet = ((u<<6)|(u+2)|move_castles);
>>>>>      rb->zetend++;
>>>>>    }
>>>>>    if( castle(rb->side,u,u-2) ) {
>>>>>      rb->zetend->zet = ((u<<6)|(u-2)|move_castles);
>>>>>      rb->zetend++;
>>>>>    }
>>>>>  }
>>>>>
>>>>>  #if BOUNDSCHECKING
>>>>>  pend++;
>>>>>  do {
>>>>>    pend--;
>>>>>    if( *pend != 64 )
>>>>>      GenMovesI(rb,*pend);
>>>>>  } while( pend > psq );
>>>>>  #else
>>>>>  do {
>>>>>    if( *pend != 64 )
>>>>>      GenMovesI(rb,*pend);
>>>>>  } while( --pend >= psq );
>>>>>  #endif
>>>>>} /* End MoveList() */



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