.TITLE   AddVersion1
;  Program to calculate the expression S = A + B
A:      .LONG    3                ; Initialize A
B:      .LONG    7                ; Initialize B
S:      .BLKL    1                ; Save room for S

;  Subroutine Add(X, Y, Sum) for calculating Sum = X + Y
;    Input:    X in R0, Y in R1
;    Output:   Sum in R2

Add:    ADDL3    R0, R1, R2       ; Sum <-- X + Y
        RSB                       ; Return from subroutine

;  The main program:

        .Entry   ByValueInRegisters, 0
;    Call Add (A, B, S)
        MOVL     A, R0            ; R0 <-- A
        MOVL     B, R1            ; R1 <-- B
        BSBB     Add              ; Call the subroutine
        MOVL     R2, S            ; Save S
        $EXIT_S
        .END     ByValueInRegisters