Because the Go assembler doesn't have those instructions built in most likely.

That sort of thing is quite common in Go assembler. The assemblers are a little primitive and they force the assembly language for each processor into a common pattern, so when you are writing ARM assembler for instance, everything is backwards.

I imagine having rationalised the assemblers between processors somewhat it makes the core developers lives easier though who have to lightly touch lots of different processor assembler.

Backwards from AT&T point of view, right?

Because for me it feels very natural, given the Z80 and Intel Assembly.

The Golang assembly does not support all instructions, we've created a tool (see https://github.com/minio/asm2plan9s) to assist in translating instructions into their opcode equivalents.

Damn. That's neat. I wrote my own python script to translate whatever `as` spits out into BYTE $.... your tool'd have been neat when I wrote this http://blog.chewxy.com/2016/07/25/on-the-memory-alignment-of...

Nice blog, and the tool would have helped indeed.

And also, memory allocation is not the most obvious topic in Go/Golang assembly...