Author: Uri Blass
Date: 12:16:52 01/10/03
1)How do I use assembler code under C to count the number of 1's in a bitboard?
I do not know how to copy assembler code from crafty.
I understood from previous post that the relevant code is in crafty but I do not
know how to copy it correctly with all the #defines in crafty.
I understood that there are some relevant codes(x86.s, vcline.h that I could not
find and boolean.h
2)I tried a code of dieter and got warning from the compiler(see the bottom of
this post for that code)
warning C4244: '=' : conversion from 'unsigned __int64 ' to 'unsigned long ',
possible loss of data
Note that I changed
int PopCount(unsigned long long a)
to
int PopCount(BitBoard a)
I also have in my code
typedef unsigned __int64 BitBoard;
I also never use the word long in my program except the code that I copied from
Dieter and I use int for 32 bit numbers.
The warning was about w=
int PopCount(BitBoard a)
{
unsigned long w;
int n = 0;
w = a&0xffffffffUL;
if (w)
do
{
n++;
}
while ((w &= w-1) != 0);
w = (a>>32)&0xffffffffUL;
if (w)
do
{
n++;
}
while ((w &= w-1) != 0);
return n;
}
Uri
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