Date: Wed, 12 Nov 1997 17:21:08 -0800 (PST) Message-Id: <199711130121.RAA04349@adit.ap.net> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" To: Jan Hubicka From: Nate Eldredge Subject: Re: Unoptimal implementation of pc.h Cc: djgpp AT delorie DOT com Precedence: bulk At 08:38 11/12/1997 +0100, Jan Hubicka wrote: >> At 05:23 11/11/1997 +0100, Jan Hubicka wrote: >> >Hi >> >In file inlines/pc.h in those outport* inport* functions are port always >> threaded as "d" (edx) >> >but you should also use an constant port "N" >> >so I think using "Nd" instead of "d" should save few instrucions and >> register or not? >> No. The "N" constraint is only intended for the compiler. It doesn't make >> sense to use it for inline asm, since the compiler doesn't know >> ahead-of-time what port will be written to. Its only choice is to load the >> port number into the dx register. >> (Also, the constant-port form of `in'/`out' only works for port numbers up >> to 0xFF, which is pretty useless.) >Well, I tries this "Nd" constraint and it worked as I expected. >out(20,20); used constant >out(256,20); used edx >and variables used edx...whats bad on that? Oh really! Wow! I didn't think the compiler was that smart. I need to not underestimate GCC anymore. :) In that case, maybe it is a good idea. Anyone else think so? Nate Eldredge eldredge AT ap DOT net