[sgerenser]

It’s because Apple’s AMX was an early, in-house built version of what was eventually released by Arm as SME. Apple adopted SME in the M4 and dropped AMX, but as long as you were using their Accelerate framework instead of directly writing AMX code (which they told people not to do), you wouldn’t notice.

Now that they’re using “standard” SME, it shouldn’t be a problem to write SME assembly opcodes directly, although I suspect Apple themselves is still probably sparse on the documentation. I’m not aware if there’s any way to use intrinsics or something slightly higher level than inline-ASM, but lower level than the Accelerate framework.