Hi,
It it possible to use the code space for address space

This gives me no sense, you too? Did you mean for data space?
If so then you may use CODE space as a place to hold constants there. It is not possible to use CODE segment for keeping a variable which value is written during program. There is command MOVC A,@A+DPTR but no MOVC @DPTR,A etc.

Regards,
Oleg