Grant Edwards @ Thu, 14 Feb 2008 00:10:27 +0000 (UTC) > > On 2008-02-13, Oleg Verych <[email protected]> wrote: >> Grant Edwards @ Wed, 13 Feb 2008 18:55:32 +0000 (UTC) >>> >>> On 2008-02-13, Oleg Verych <[email protected]> wrote: >>> >>>> Alignment of members as well as whole structure is arbitrary. That's why >>>> mspgcc have "packed" attribute, but it's without (implicit for many >>>> developers) magic. >>> >>> Are you saying tht the MSP430 backend gcc does not correctly >>> generate code to access misaligned struct members the way that >>> other backends (e.g. ARM) do? >> >> Based on what i've saw in this thread -- yes. > > If that's the case, it might need to be spelled out a little > more clearly in the manual.
> It wasn't clear to me that the web page mentioned earlier was saying > that. That web page seemed to be talking about peripheral registers. Any unaligned struct members *and* structures themselves on RISC generally, i guess. Better to ask developers. There is an alternative -- byte by byte access. But how efficient it can be? Better to have good _design_ right from the start. As for portability, it's interesting to notice TCP/IP data structures and (Intel-ish) USB, and what problems latter has on archs without hardware support for unaligned access... ______
