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Re: powerpc & unaligned block moves with fp registers
- To: DJ Delorie <dj at redhat dot com>
- Subject: Re: powerpc & unaligned block moves with fp registers
- From: David Edelsohn <dje at watson dot ibm dot com>
- Date: Thu, 01 Nov 2001 23:59:12 -0500
- cc: gcc at gcc dot gnu dot org
>>>>> DJ Delorie writes:
DJ> Um, the 603e in big-endian mode can do unaligned integer moves all by
DJ> itself, but traps sufficiently unaligned fp moves, according to the
DJ> programming manual from Motorola. I'm not sure why you'd think that
DJ> it's the operating system's fault that it's doing this, especially in
DJ> an embedded system with no operating system.
Because this is a performance issue. SLOW_UNALIGNED_ACCESS
already discourages "sufficiently unaligned fp moves". Only the
customer's OS requires stricter alignment just for FPRs. The current
definition of SLOW_UNALIGNED_ACCESS is good for everyone else.