The current Go assembler does not accept zero shifts, such as "op $0, Rd" and "op $(0<<(16|32|48)), Rd" instructions.

Examples:

	MOVK $(10<<32), R20     <=>      movk x20, #10, lsl #32
	MOVZW $(20<<16), R8     <=>      movz w8, #20, lsl #16
	MOVK $(0<<16), R10 will be reported as an error by the assembler.

Special Cases.

(1) umov is written as VMOV.

(2) br is renamed JMP, blr is renamed CALL.