Author: Tony Werten
Date: 02:23:25 02/27/03
Go up one level in this thread
On February 26, 2003 at 14:04:16, Uri Blass wrote:
>I had the following code in my program
>
>do
>{
>...
>if (info[target]==EMPTA)
> target+=8;
>else
> target=64;
>}
>while (target<64)
Less branches:
do
{
...
tmp:=(info[target]!=EMPTY); // maybe typecast to int ?
target+=(tmp*256)+8;
} while (target<64);
if (target>256) target=64;
But I'm not sure if this works in C. (In pascal compares are garantied to return
0 or 1 )
Tony
>
>I found that changing it to else break did not do my program faster.
>
>I think that with break I have branches and without break the compiler can
>translate it to
>
>target=((info[target]==EMPTA)?target+8:64);
>
>My questions are
>1)How can I write the code as branchless code without target=64 that is a waste
>of time?
>
>2)I understood from previous discussion that for some reason ? is considered
>branchless code.
>What is the reason for it.
>
>It seems to me that using ? is the same as using if.
>If it is not the case then what is the difference?
>
>Uri
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