How To Lock The Store Procedure And Allow One Process To Acces It At A Time

Hello:

I run one process that calls the following the store procedure and
works fine.

create PROCEDURE sp_GetHostSequenceNum
AS
BEGIN

SELECT int_parameter_dbf + 1
FROM system_parameter_dbt
WHERE parameter_name_dbf = 'seqNum'

UPDATE system_parameter_dbt
SET int_parameter_dbf = int_parameter_dbf + 1
WHERE parameter_name_dbf = 'seqNum'

END
GO


If I run two processes that call the above store procedure, I might
occasionally get the dirty data of int_parameter_dbt. I guess that is
caused by two processes accessing to the same resource simultaneously.
Is there any way to lock the store procedure call from MSSQL Server
and allow only one process to access it at a time?

Thanks for help.

Best Jin