OP_IMMED_A_SRC
FIELD_PREP(OP_IMMED_A_SRC, areg) |
reg = FIELD_GET(OP_IMMED_A_SRC, instr);
if (unreg_is_imm(FIELD_GET(OP_IMMED_A_SRC, *instr))) {
*instr &= ~FIELD_PREP(OP_IMMED_A_SRC, 0xff);
*instr |= FIELD_PREP(OP_IMMED_A_SRC, immed & 0xff);