Date: Fri, 15 Dec 1995 17:37:00 -0800 From: David Greenman <davidg@Root.COM> To: Bruce Evans <bde@zeta.org.au> Cc: CVS-committers@freefall.freebsd.org, cvs-sys@freefall.freebsd.org Subject: Re: cvs commit: src/sys/i386/isa if_ed.c Message-ID: <199512160137.RAA02079@corbin.Root.COM> In-Reply-To: Your message of "Sat, 16 Dec 95 12:17:39 %2B1100." <199512160117.MAA07889@godzilla.zeta.org.au>
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>> No, you apparantly don't understand what's happening in there. In the PIO >>case, the "base" is 0 and the offset is just an offset relative to zero. The >>upper bits will never be non-zero. > >I see. Pointer variables are being used to hold pointers for the memory >mapped case and offsets for the pio case. Actually, the upper bits will >always be nonzero because of this code for the NE case: > > sc->mem_start = (char *) 8192 + sc->isa16bit * 8192; Umm, well, it depends on what "upper bits" we're talking about. The NE1/2000 internal layout has the NIC memory starting at offset 8192 or 16384 depending on whether it's an NE1000 or an NE2000 (8 or 16 bit). In either case, bit 15 will always be 0. All 16 bits of the offset are used and are important. -DG
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