CGEN_INSN_INT is typedef:ed as an "unsigned int" and CGEN generates alot of code that thinks that an insn or operand can fit into a long or int. what does your opcodes/foo-desc.h have defined for CGEN_INT_INSN_P? this should be zero when you have any instructions larger than what fit into an int. if not, i suspect problems in your insn formats. .mrg.