There is no easy way to do this using stored procedure or query. You can try querying sys schema that contains all meta data about database.
For example you can get object definition for stored procedures like this
select OBJECT_SCHEMA_NAME(P.object_id) as [Schema], P.name as [Procedure Name] ,c.text as Procedure_Definition
from sys.procedures P
inner join sys.syscomments C on P.object_id = C.id
Using this query you can join two database tables and select those where database1.sys.syscomments.text is not qual to database1.sys.syscomments.text
Another option is to use a third party tool such as ApexSQL Diff or any similar tool on the market.