Albert ARIBAUD albert.u.boot@aribaud.net writes:
Please do not advise using native unaligned accesses on code that is not strictly used by ARMv6+ architectures: the present code, for instance, might be run on pre-ARMv6 or non-ARM platforms, and thus, should never assume ability to perform unaligned accesses natively.
I'm advising no such thing. I said two things:
Declaring a struct with the 'packed' attribute makes gcc automatically generate correct code for all targets. _IF_ the selected target supports unaligned ldr/str, these might get used.
If your target is ARMv6 or later _AND_ you enable strict alignment checking in the system control register, you _MUST_ build with the -mno-unaligned-access flag.
Then I apologize; I had read "Note that on ARMv6 and later ldr/str support unaligned addresses unless this is explicitly disabled in the system control register" as a suggestion to use that capability.
If building for ARMv6 or later, I do suggest allowing unaligned accesses. The moment you add -march=armv6 (or equivalent), you allow for a number of things not supported by older versions, so why not unaligned memory accesses?