dmd Arm64 - first function compile!

[max haughton]

On Sunday, 2 June 2024 at 06:30:18 UTC, Walter Bright wrote:
> In recent days, it has become abundantly clear that the x86 
> architecture appears to be headed for obsolescence. The Arm 
> processor is taking over. The Mac is dropping the x86 in favor 
> of Arm. Microsoft has announced Arm laptops.
>
> Even my Raspberry Pi is an Arm64.
>
> What to do about dmd? Many people in the D community have 
> expressed interest in creating an Arm backend for D. Since 
> implementing a 64 bit code generator is trivial, I thought I'd 
> look into it.
>
> I bought a couple books on the Arm, and have been studying the 
> datasheet for it. Most of the backend can be repurposed to Arm. 
> The structure of it can remain the same.
>
> The goal is Arm64, not Arm32. Since even the Pi is Arm64, there 
> is no purpose in supporting the Arm32.
>
> Hacking away listening to Brain Pain metal, the first function 
> compiles:
>
> ```
> void foo() { }
> ```
>
> dmd -c test.d -vasm
>
> producing:
>
> ```
> _D4test3fooFZv:
> 0000:   D6 5F 03 C0  ret
> ```
>
> And there it is! Nothing else works, but what the heck.
>
> https://github.com/WalterBright/dmd/commit/04546a8f72c10a09764f23675c67c5fbdf29628c

https://developer.arm.com/Architectures/A64%20Instruction%20Set%20Architecture

Warning: Arm64 doesn't really exist other than as an informal 
name / thing apple use sometimes, aarch64 is the name you'll find 
in the manual, with A64 being the name of the instruction in 
particular (apparently, not really sure how the versioning works 
there)