.DEFINE_IREG A0     16      ; A0 is integer register 16
            .DEFINE_IREG A1     R17     ; A1 is integer register 17,
                                        ;  defined in terms of the
                                        ;  predefined R17 register symbol
            .DEFINE_IREG PTR    A0      ; PTR is integer register 16,
                                        ;  defined in terms of the
                                        ;  previously-defined A0 register
                                        ;  symbol
            .DEFINE_FREG $F0    0       ; $F0 is floating register 0
            .DEFINE_FREG $F1    F1      ; $F1 is floating register 1,
                                        ;  defined in terms of the
                                        ;  predefined F1 register symbol
            .DEFINE_FREG RADIUS $F1     ; RADIUS is floating register 1,
                                        ;  defined in terms of the
                                        ;  previously defined $F1
                                        ;  register symbol
            .DEFINE_IREG X1     R5      ; X1 is integer register 5,
                                        ;  defined in terms of the
                                        ;  predefined R5 register symbol
            .DEFINE_IREG X1     5       ; 2nd definition is the same
                                        ;  value, so no diagnostic
                                        ;  results
            .DEFINE_IREG X1     7       ; Warning: redefinition with a
                                        ;  different value
            .DEFINE_IREG X2     F5      ; Error: cannot define an integer
                                        ;  register in terms of a
                                        ;  floating register

            LDQ         R1, (PTR)       ; LDQ R1, (R16)
            LDG         RADIUS, (A1)    ; LDG F1, (R17)