30 Jun
2004
30 Jun
'04
5:33 p.m.
At Wed, 30 Jun 2004 16:37:59 +0100 (BST),
Mike Rawes wrote:
--- Pete Bessman <ninjadroid(a)gazuga.net> wrote:
Ah. Now I get to find all the places in my code that can benefit from
that. If you assign a float value into an int variable, is that an
implicit cast?
At Mon, 28 Jun 2004 19:56:50 +1000,
Erik de Castro Lopo wrote:
The lrint converts the float value to an int (a lot) faster than a
simple cast.
double fractional = 0.0, increment = 0.1;
int integer = 0;
for (;;)
{
/* Bunch of other code. */
fractional += increment ;
integer += lrint (floor (fractional));
fractional -= floor (fractional);
}
I don't understand this lrint (floor ()) stuff. floor() returns a
truncated integer value, so what's the point of calling lrint() on
that? The floor is to get around the rounding rule used by
the FPU when the float
value is exactly halfway. It rounds to even numbers, at least it does on an
AthlonXP:
Good to know, thanks for the tip. Although, just using lrintf(val)
would be wrong anyway because it would round up if fmod(val, 1.0) >
0.5, right?
-Pete
www.gazuga.net