If the source register (SRC1) is not cleared (one bit is not zero), then either ;
Short version : the destination register (SRC2) is cleared
Long version : the destination register (SRC2) is set to the value of Imm16 (sign-extended).
This is one of the conditional instructions of the CMOV group, see also : CLR, CZ, CO/CNE/CNO/CE, CS/CNS