You're assuming that the asm syntax is targeted at human readability, when it's at least as much to ease the complexity of the assembler and disassembler.

If the FMA instruction syntax was designed for readability, then it would have used 4-argument syntax with a requirement for two registers to match instead of using the 1/2/3 encodings. But the reason why it uses those names instead is that it's more consistent with the instruction encoding and the format of most other vector instructions: the register/memory argument is last.

Similarly, x86 vector instructions that take an immediate byte cram a bunch of options into that byte, such as shuffle masks or operation options. The assembly syntax does not help constructing this byte at all. But that's because it's meant to map straightforwardly to the instruction encoding, not to be easy to manually read or write.

ARM assembly tends to be a bit more consistent, but has some similar quirks. The majority of ARM instructions are dst,src, but store instructions are reversed as src,dst so they have the memory argument second just like load instructions.

>You're assuming that the asm syntax is targeted at human readability, when it's at least as much to ease the complexity of the assembler and disassembler.

I think you misunderstand my meaning. I know why things are like this. I was musing on the consequences of that. When the target moved aware from human readability then it also actively discourages human attention, lessening the chance of innovation. In my own work, I have always thought that maximising the general utility of things is better than targeting a 'use case' so that others might come up with ideas for use that I hadn't considered.

A worrying thought is that companies might be motivated to discourage innovation outside of their own control.