Author: Filip Tvrzsky
Date: 03:54:01 02/20/03
Go up one level in this thread
On February 20, 2003 at 06:26:39, Uri Blass wrote:
>On February 19, 2003 at 10:45:27, Dezhi Zhao wrote:
>
>>On February 19, 2003 at 09:57:13, Uri Blass wrote:
>>
>>>On February 19, 2003 at 09:41:35, Dezhi Zhao wrote:
>>>
>>>>On February 19, 2003 at 06:39:49, Uri Blass wrote:
>>>>
>>>>>I try to do movei faster and there are things that are supposed to do it
>>>>>slightly faster but for some reasons do it slower so I deleted them(Maybe it is
>>>>>better if I ignore it because it is a compiler optimization noise but I do not
>>>>>like to see the program slower even if it is only 0.1% slower).
>>>>>
>>>>>Note that I do not use now compiler optimization except optimize for speed with
>>>>>visual C++6.
>>>>>
>>>>>
>>>>>Here is an example:
>>>>>My function of adding pawn moves to the stack of moves get 2 numbers(from,to).
>>>>>
>>>>>I found that special functions to generate white moves one square forward,white
>>>>>moves 2 pawns forward,black pawns one square forward,...helped me to do movei
>>>>>faster.
>>>>>
>>>>>Common sense say that now I do not need 2 numbers in my functions because
>>>>>I always have to=from-8 in
>>>>>
>>>>>Here is my function.
>>>>>to is always from-8 and the question is if I can take advantage of that fact.
>>>>>
>>>>>static void gen_quietblackslowpawns(int from,int to)
>>>>>{
>>>>> gen_t *g;
>>>>> if (to<=7)
>>>>> {
>>>>> gen_promote(from,to);
>>>>> return;
>>>>> }
>>>>> g=&gen_dat[first_move[ply+1]++];
>>>>> g->m.b.from=(char)from;
>>>>> g->m.b.to=(char) to;
>>>>> g->m.b.promote=0;
>>>>> g->m.b.bits=16;
>>>>> #if MODE!=MODE_PERFT
>>>>> g->score = history[from][to];
>>>>> g->index=-10000;
>>>>> #endif
>>>>>}
>>>>
>>>>I think you can get a little from that fact. It will save a few push and pop
>>>>operations.
>>>>
>>>>By the way, if you really want to optimize this function, you should consider
>>>>re-designing the b structure so that the move can be saved in a single write
>>>>operation, instead of 4.
>>>
>>>Thanks for the advise but how do I do it
>>>
>>>I have the same data structure as tscp here(Note that 90% of my code is
>>>different than tscp but I copied part of it's data structures).
>>>
>>>Here is my b structure
>>>
>>>typedef struct
>>>{
>>> char from;
>>> char to;
>>> char promote;
>>> char bits;
>>>}
>>>move_bytes;
>>>
>>>typedef union
>>>{
>>> move_bytes b;
>>> int u;
>>>}
>>>move;
>>>
>>>
>>>I can think about deleting the b and have something like
>>>g->m.u=from+(to<<8)+(promote<<16)+bits<<24) but the question in that case is if
>>
>>yes. you can go this way. for this function, the last 2 items are simple
>>constants anyways.
>>
>>>it is not going to do accesing the varaibles slower because there are places in
>>>the code when I use bits and now I will need to use things like u>>24.
>>>
>>>I have no idea about the price of these things so I cannot evaluate speed here.
>>>
>>>Uri
>>
>>Not that complicated if you think it twice. I do know the semantics of bits
>>thare. However I assume it is a flag. If it is the case, you do not need to do a
>>shift to make it flat. Consider testing the other way without shift operations:
>>u & (16 << 24)
>>So you can avoid shift operations in many cases. So you still gain something
>>here.
>>
>>dzhao
>
>I try it at this moment(I do not know if it is going to make the code faster so
>I saved the previous code).
>
>The problem is how to make my code readable at the same time.
>
>I deleted the m.u and m.b.from,m.b,to,...
>and have only m that is an integer.
>
>I try to use some defines
>
>#define mfrom (m&63)
>#define mto ((m>>8)&63)
>#define mpromote ((m>>16)&63)
>#define mbits ((m>>24)&63)
>
>It was not enough so I added the following defines
>
>#define gen_dat_i_mfrom (gen_dat[i].m&63)
>#define gen_dat_i_mto ((gen_dat[i].m>>8)&63)
>#define gen_dat_i_mpromote ((gen_dat[i].m>>16)&63)
>#define gen_dat_i_mbits ((gen_dat[i].m>>24)&63)
>
>I see that it is not enough and I need the same for other varaibles that are of
>the same type.
>
>I do not like it so I went back to my previous code
>
>Thanks in advance for advices.
>
>Uri
Why do you not use inline functions? I think this is just the case to employ
them.
I have such a code in my engine:
inline unsigned char From(MOVE x) { return (unsigned char) ((x >> 8) & 0x77);
}
and so on.
Filip
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