What does "MSL" (shift in ones) in arm64 assembly stand for?

Question

In an assembler instruction like

movi    v30.2S, #0x3c, msl #0x8

msl will cause that the value 0x3cff (value is shifted left and ones are inserted at the bottom) is moved to the target but what does MSL stand for? For example LSL stands for "Logical Shift Left".

Answer 1

I'm not 100% sure on this, but based on the capstone documentation, it may stand for "Masking shift lift".

Only thing I question about it is that it says lsl may stand for "Logical shift lift", and not "Logical shift left", so maybe "Masking shift left"?