legion/docs/readmes/README.cpu_version

**Setting CPU version information**

In the processor section of the conf file, you can specify
mask/impl/manuf values.  If any values are not specified
in the conf file, then the default values, as defined in the
respective processor header file, will be used.

e.g.

to change only 'impl' to '0xbeef' on Niagara (manuf/mask at
default):

In conf file:

        processor "niagara" {
                ...
                ...
                ver "impl" 0xbeef;  // set impl to '0xbeef'
        }

to change 'manuf' to '0x5a5a', 'impl' to '0xbeef', and 'mask' to
'0x77':

                ver "manuf" 0x5a5a "impl" 0xbeef "mask" 0x77;

                or

                ver 0x5a5abeef77000000;