Author: Filip Tvrzsky
Date: 16:50:56 03/29/03
Go up one level in this thread
On March 29, 2003 at 19:37:22, Sune Fischer wrote:
>On March 29, 2003 at 14:16:15, Russell Reagan wrote:
>
>>This will return the location of the least significant bit. Dieter helped me
>>with this one some time ago. The syntax that GCC uses for inline assembly is
>>AT&T syntax I believe, as opposed to the Intel syntax, which is what MSVC uses.
>>I'm not sure if this is the most optimal way to do it, but it worked for me, and
>>I figure that Dieter knows this stuff way better than me :)
>>
>>int LowBit (Bitboard b) {
>> int result;
>> __asm__ volatile ("
>> movl $-33, %0
>> bsfl %2, %0
>> addl $32, %0
>> bsfl %1, %0"
>> : "=q" (result)
>> : "g" ((unsigned long)b), "g" ((unsigned long)(b>>32))
>> : "cc" );
>> return result;
>>}
>
>Hmm, I get warnings:
>
>"bits.h:117:27: warning: multi-line string literals are deprecated"
>
>-S.
Please, see my previous message
http://www.talkchess.com/forums/1/message.html?291092
So modify the code following way:
int LowBit (Bitboard b) {
int result;
asm volatile ("\n\
movl $-33, %0 \n\
bsfl %2, %0 \n\
addl $32, %0 \n\
bsfl %1, %0 \n"
: "=q" (result)
: "g" ((unsigned long)b), "g" ((unsigned long)(b>>32))
: "cc" );
return result;
}
Filip
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