Hi, I was given your email as address for patches to gdb. Please advice if you are not the correct person. Problem. Gdb version 5.3 target h8300-coff. Machine h8300h. Simulator Demonstration of fault. set machine h8300h target sim Gdb Abort! Cause of fault. Incorrect definition of number of machine registers in tm-h8300.h Patch diff -c tm-h8300.h tm-h8300.h-orig Fix is alpha as there is another definition of NUM_REGS in h8300-tdep.c , these two need to be merged and integrated into the gdb definitions for h8300 registers. -- Philip Quaife Q Solutions