Aarch64 ISA additions (SM3, SM4, SHA3)

[Tamar Christina]

Hi Jeff,

> 
>   * What versions of GCC offer SM3, SM4 and SHA3?

They will be supported starting with GCC 8.

>   * What is AES and SHA2? How is it different from +crypto?
> 

In short, +crypto = +eas +sha2. We are retro-actively splitting the Armv8.0-A Cryptographic extensions into two groups
Based on the algorithm family. 

For more on this see the Arm ARM (version ca or newer) on page C3-219 in the note. 
https://developer.arm.com/products/architecture/a-profile/docs/ddi0487/latest/arm-architecture-reference-manual-armv8-for-armv8-a-architecture-profile 

>   * Can we now use, say, -march=armv8.4-a+aes or -march=armv8.4-a+sha2
> instead of -march=armv8-a+crypto?

Yes, that's correct. 

Regards,
Tamar

> 
> Jeff