On Wednesday, August 24, 2016 11:57:08 PM CEST Arnd Bergmann wrote: > > I'm not familiar with those classifications, but from what I can tell, > > BE32 describes it correctly. I'll see if I can get someone to verify > > this. Is there a reason it's not widely used anymore? Perhaps > > something related to supporting misaligned word-sized loads/stores? > > The main problem I see is that you can't easily use MMIO registers that > are not 32-bit wide -- you end up having to flip not just the register > contents but also the lower bits of the address in order to reach > the right contents of the register. > Actually there is a much more serious problem with BE32/LE32 mode: doing unaligned access to RAM is a huge pain at the HW level, and also when emulating it in the kernel on CPUs that require aligned access. In ARM THUMB2 mode, you can even have unaligned 32-bit instructions. Arnd -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
