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Date:      Wed, 26 Apr 2006 10:04:46 -0600 (MDT)
From:      "M. Warner Losh" <imp@bsdimp.com>
To:        mj@feral.com
Cc:        cvs-src@FreeBSD.org, scottl@samsco.org, src-committers@FreeBSD.org, cvs-all@FreeBSD.org, jhb@FreeBSD.org
Subject:   Re: cvs commit: src/sys/dev/bce if_bcereg.h
Message-ID:  <20060426.100446.128616681.imp@bsdimp.com>
In-Reply-To: <20060425165324.M64286@ns1.feral.com>
References:  <444E7BFE.4040800@samsco.org> <20060425.173236.74726638.imp@bsdimp.com> <20060425165324.M64286@ns1.feral.com>

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In message: <20060425165324.M64286@ns1.feral.com>
            Matthew Jacob <mj@feral.com> writes:
: 
: > The problem is that PAE's bus_size_t is a 32-bit quantity, when it
: > should be a 64-bit quantity:
: >
: > #ifdef PAE
: > typedef uint64_t bus_addr_t;
: > #else
: > typedef uint32_t bus_addr_t;
: > #endif
: > typedef uint32_t bus_size_t;
: >
: > For bus addresses, we should use bus_addr_t, of course, but the above
: > is wrong.  I don't have a PAE machine, or I'd commit my local changes
: > that fix this...
: >
: 
: Why do you believe that it should be a 64 bit quantity under PAE?
: 
: Strictly speaking, I don't believe it is. PAE allows you to *address* 
: 36 physical address bits of memory using Dual Address cycles, but the 
: underlying bus is still a 32 bit bus.

Because it expands the address space > 32 bits.

Warner



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