From: leathm AT solwarra DOT gbrmpa DOT gov DOT au (Leath Muller)
Message-Id: <199705202353.JAA10694@solwarra.gbrmpa.gov.au>
Subject: Re: float & ints & triangle3d_f
To: wapex AT silesia DOT top DOT pl (Michal)
Date: Wed, 21 May 1997 09:53:09 +1000 (EST)
Cc: djgpp AT delorie DOT com
In-Reply-To: <3381C71A.28FF@silesia.top.pl> from "Michal" at May 20, 97 05:45:30 pm
Content-Type: text
Precedence: bulk

> > This is true, but if your just checking for a < b, sub a from b, store and
> > check the sign bit. If the sign is 0 then a <= b... If you weave the code
> > properly, you can do a check in about (from memory) 5 cycles... (compared
> > to an int's 1 though)

> This is true, but the compiler won't do it for you, and I can't imagine
> writing all coparisions in assembler... so avoid it.
> There is another trick you maight find usefull. To convert float point
> to integer just add 0x59c00000 (have to be single precision fadd), store
> the result and use it as it was integer. It's only 1 clock less, but you
> have beter scheduling opportunities (can execute up to 4 integer
> instruction in a gap after fadd).
 
Doesn't this method have problems? Hmm... will have to go back to the ol'
references... :) 

Leathal.