Before we finally switch the ARM ports to ELF I think we need to decide 
how a process that is using the PTRACE interface should get the VFP 
registers on a machine that has a VFP unit (or emulator) attached.

Has a similar issue (of modifying the "struct reg" or "struct fpreg" 
layout) come up on other ports?  If I add extra space to the end of struct 
fpreg will it break existing applications that try to read or write the 
fpreg structure via ptrace()?

If so, is there a way to add new calls to the ptrace interface to read and 
write the additional registers?

R.