[Scummvm-devel] Wii & Gamecube (resp. PowerPC) vs. unaligned memory access

[A. Milburn]

On Fri, May 06, 2011 at 01:08:13PM +0200, Max Horn wrote:
> * Has single-cycle misaligned access within a doubleword boundary
> ...
> * Supports big-endian and little-endian byte addressing
> * Supports misaligned little-endian in hardware

As discussed on IRC: the PowerPC specification specifies where unaligned
memory exceptions can be expected, and the only relevant mentions for us
seem to be about multiple loads/stores in little-endian mode. These seem
to be disabled due to -mno-multiple being the default anyway? Presumably
the spec is referring to that being handled in hardware instead, here, as
opposed to misaligned big-endian not being supported (I read it as being
mandatory, and it seems to work fine).

So the problems on the Wii are most likely aliasing issues, as mentioned
further along the thread, and there shouldn't be any alignment issues
on any PowerPC processor we target.

- fuzzie