🚀 go-pugleaf

In article <1992Dec14.203631.16388@CSDNewsHost.Stanford.EDU> 
andy@SAIL.Stanford.EDU (Andy Freeman) writes:

   Does anyone know why they preferred even/odd to >=0/<0?  Sometimes one
   has to test the sign bit, so why not use it whenever one can use any
   bit to split things into two classes?

Part of the reason might be that this distinction (>=0/<0) is used
in a number of places to distinguish a system address, which has the
MSB set, from other data, eg. a PID; this is used in I/O completion:
if <0, the PID cell is reinterpreted as a routine in system space
to call, as this I/O has been started by some system component and 
not a user process.)

	Jan