Hi Simon,
On 30 May 2014, at 11:11 PM, Simon Glass sjg@chromium.org wrote:
<snip>
This code compiles on the host, so unfortunately yes. That's the same reason I had to work around the lack of handy *_u64 fdt helpers when reading the public exponent.
OK, although Linux might have replacements. But if not, perhaps add a comment as to why you need the helper function.
Will do.
[snip]
For example, if you did:
montgomery_mul(key, result, val, key->rr); /* acc = a * RR / R mod n */Yes, it's sizeof(uint32_t) - that would probably be a good thing to spell out too.
result points to tmp, which is going to be repeatedly overwritten in the loop, but we need a_scaled to stay constant (as the result of the first montgomery_mul) throughout... or did I misunderstand your point?
OK I see thanks. Perhaps add a new temporary instead of using memcpy()?
And set it up using montgomery_mul? Would that not be more expensive than a memcpy?
On the host? Not sure we care about that. I was really just wondering if an assignment is better than a memcpy() which makes assumptions about the format.
In theory it should optimise to the same code, but I'll run tests with assignment to make sure it works as expected.
Michael