Using -O3 optimization level rather than -Os results in a large speed-up
for a minor code size increase for the RSA code with our current GCC
toolchain.
Add the CONFIG_RSA_OPTIMIZED option to do it on platforms which are not
too size-constrained.
On cortex-M4 based STM32L432, I'm measuring a 37 to 40% speed increase
(depending on CPU frequency) for a 200 bytes code size delta.
Signed-off-by: Vincent Palatin <vpalatin@chromium.org>
BRANCH=none
BUG=none
TEST=manual: benchmark RSA2048 with F4 exponent on STM32L432:
-Os -O3
@16Mhz 185163 us --> 111942 us
@80Mhz 39286 us --> 24582 us
Change-Id: I8c2e4b757f037f4f645fb73ba0faaaa471b24896
Reviewed-on: https://chromium-review.googlesource.com/445218
Commit-Ready: Vincent Palatin <vpalatin@chromium.org>
Tested-by: Vincent Palatin <vpalatin@chromium.org>
Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>
a1c8d50e9b