Date: Sat, 3 Apr 1999 13:43:46 -0500 (EST) From: Alfred Perlstein <bright@rush.net> To: Dennis <dennis@etinc.com> Cc: hackers@freebsd.org Subject: Re: What does the "s" in insl and insw mean? Message-ID: <Pine.BSF.3.96.990403134213.4169R-100000@cygnus.rush.net> In-Reply-To: <199904031744.MAA26618@etinc.com>
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On Sat, 3 Apr 1999, Dennis wrote: > At 11:39 AM 4/3/99 -0500, you wrote: > >On Sat, 3 Apr 1999, zhihuizhang wrote: > > > >> > >> The instructions insl() and insw() should read a long word (l) or a word > >> (w) from a specified I/O port. But what does the "s" in both instructions > >> stand for? I can not find it in the Info files. > > > >in from port string operation > > > >it grabs a byte/word from the port, stores it into DS:DI and increments > >DI, (that's in x86 real mode) afaik in prot mode it prolly just stores > >to the segemtn pointed to DS and uses EDI. > > > >The opcodes without 's' use al/ax/eax for the destination. > > Its important to note that is a string read in that it will read multiple > words (count of CX) ....of REP fame for memory copies. If you > have an IO mapped card (rather than a memory mapped on) ins? > functions can simulate a memory copy from IO space. er, isn't that only if you prefix the opcode with the 'rep' prefix? -Alfred To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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