I don't think scanbit or scanbyte are implemented. Also I don't understand how to even begin to add instructions. The file i960-desc.c looks like the place to start editting but it says it is machine generated by cgen but the Makefile does not seem to have any rules to regenerate it. Advice? -- Joel Sherrill, Ph.D. Director of Research & Development [EMAIL PROTECTED] On-Line Applications Research Ask me about RTEMS: a free RTOS Huntsville AL 35805 Support Available (256) 722-9985