Author: Ulrich Tuerke
Date: 08:59:42 04/11/03
Go up one level in this thread
On April 11, 2003 at 11:09:47, Uri Blass wrote:
>only one time or not done often.
>
>I have task that I do only one time and I may do my code shorter
>by adding functions.
>
>Note that they are a small minority of the code so
>I do not expect a big reduction.
>
>Here are some examples:
>
>1)In the code that build the array of knightmoves I have
>8 similiar if.
>
>if (fil>=2&&rank>=1)
> {
> knightmove[sq][i]=index(fil-2,rank-1);
> direction[sq][knightmove[sq][i]]=dknight;
> i++;
> }
>
>Is there an advantage in changing it to something like
>
>if (fil>=2&&rank>=1)
>{
>buildknightarrays(sq,i,fil-2,rank-1);
>i++;
>}
>
>or maybe it is even better to give buildknightarrays
>a pointer to i to save the i++ that I do 8 times.
>
>
>2)In my code for setup position I have the following code
>
> case 'n':
> info[square]+=KNIGHT;
> valuepieces+=3;
> if (color(square)==LIGHT)
> valpieces[0]+=3;
> else
> valpieces[1]+=3;
> break;
>
>I can replace 3 by piece_value[KNIGHT]
>replace 0 by LIGHT and replace 1 by DARK
>
>I can also have a function
>putpiece(int square,int piece)
>{
>info[square]+=piece;
>valuepieces+=valpieces[piece];
>if (color(square)=LIGHT)
> valpieces[LIGHT]+=valpieces[piece];
>else
> valpieces[DARK]+=valpieces[piece];
>}
>
>Questions:
>
>
>1)Is there an advantage for doing these things except doing the code more easy
>to read?
I don't think so. It's solely for easy readability, and perhaps also to ease
maintenance.
A function call even generates a tiny runtime overhead. However, some compilers
offer to define "inline" functions; in this case there is no runtime penalty.
>
>2)Is it better to add a special file to the project of things that I do
>not do often(like initializing arrays every time that I setup a new FEN)?
I think that it may make sense to collect the performance-critical functions in
modules. It could be easier to load the performance critical code into the
cache. However I think that this may depend a lot on your build environment.
Uli
>
>I remember a claim of christhope that he tried to limit the
>things that the program does often to 64k or 128k(I am not sure about the
>number) but I have no idea how much memory movei use for the main things that
>it does.
>
>The main things that it does include the move generator
>and the search but both things are done in different files in the project.
>
>Uri
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