How to test Aarch32 execution environment on Aarch64?

[Kyrill Tkachov]

On 25/06/16 00:01, Jeffrey Walton wrote:
> Hi Everyone,
>
> I have an Aarch64 dev board. I want to build out a test case for both
> CRC and Crypto extensions in an Aarch32 execution environment. Its not
> clear to me how to do it.
>
> I know I can activate CRC with (Crypto is similar):
>
>      gcc -march=armv8-a+crypto ...
>
> My question is, what do I add for the 32-bit binary? Is it as simple
> as -m32, or do I need to do something else?

The AArch32 execution state is available through the arm port of gcc,
as it is mostly compatible with ARMv7-A and earlier versions of the architecture.
So if you're targeting a Linux environment you'll need a toolchain
targeting something like arm-none-linux-gnueabihf.
Once you're compiling with an arm toolchain the CRC extension can be enabled through
-march=armv8-a+crc or selecting an -mcpu option that enables it.
To enable the Crypto extension you'll have to specify the right -mfpu option.
Look at the documentation at:
https://gcc.gnu.org/onlinedocs/gcc/ARM-Options.html

Kyrill

> Thanks in advance.
>
> Jeff
>