The .REG
directive assigns a predefined or user-defined typed-register to
a symbol, which becomes a synonym for the typed-register.
Syntax  | 
  | 
 label  .REG   [typed_register]
Parameters  | 
  | 
- label
 A user-defined register name.
- typed_register
 Must be one of the predefined Assembler registers
or a previously defined user-defined register name All predefined
Assembler registers begin with %.
Example  | 
  | 
This example defines the register shift
as a synonym for control register eleven. %sar
is a predefined synonym for control register eleven, the shift-amount
register.