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Re: packing/unpacking 4-octet longs
- From: Andrew Cagney <ac131313 at cygnus dot com>
- To: Richard dot Earnshaw at arm dot com
- Cc: twall at oculustech dot com, gdb at sources dot redhat dot com
- Date: Wed, 05 Dec 2001 13:42:20 -0500
- Subject: Re: packing/unpacking 4-octet longs
- References: <200112051645.QAA06737@cam-mail2.cambridge.arm.com>
> I'm not aware of this affecting the ARM (except in that FPA format doubles
> and long doubles always have the word with the exponent at the lowest
> address, but there's nothing in the IEEE FP specs that says this is
> invalid). In particular, storing a word, or multi-word, at an unaligned
> address does not change the order of bytes in memory, so
> memcpy(unaligned_address, aligned_address, sizeof(some_word))
> does not require diddling with the internal order (or have I misunderstood
> the problem?)
That was a useful manual :-) See 5-21 where it explains that a
misaligned 32bit access gets rotated before it is stored :-/
enjoy,
Andrew