Fixed a bug that the little-endian Microblaze does not work when MBEDTLS_HAVE_ASM is defined

[Kazuyuki-Kimura]

Description

Fixed a bug that the little-endian Microblaze does not work when MBEDTLS_HAVE_ASM is defined.
Fixes issue #2020

Status

READY

Requires Backporting

Yes
Which branch?
2.16

Migrations

NO

[mpg]

Hi @Kazuyuki-Kimura and thanks for your contribution! Were you able to reproduce the bug and verify your fix on the affected platform?

[Kazuyuki-Kimura]

Without knowing about this bug, I installed mbedTLS in a mail client I was making, and it stopped just like #2020, so I think I was able to reproduce it.
When I wrote a new assembler code to improve the speed and pass the test, I compared the results and found that the only difference was the order in which the 64-bit data was imported from memory.
microblaze allows you to choose the endianness when you embed it in your FPGA.
When we first released it, I think we created the code to work with big-endian cores.
We have passed all the necessary tests and confirmed that we can send emails to the SMTPS server without any problems.

[mpg]

Thanks ! Since we don't have the relevant hardware for testing ourselves, it's important to know that your patch was tested.

[mpg]

The patch looks good to me, just one nit-pick: could you rebase on top of current development in order to avoid the merge commits? Thanks!