VMS Help MACRO, VAX MACRO Assembler, Instructions, ADDxx  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Purpose:        Perform arithmetic addition
    Format:         opcode add.rx,sum.mx                   ;2 operand
                    opcode add1.rx,add2.rx,sum.wx          ;3 operand
    Operation:      sum = sum + add                        ;2 operand
                    sum = add1 + add2                      ;3 operand
    C. Codes:       N = {sum LSS 0}, Z = {sum EQL 0}, V = {overflow},
                    C = 0 (floating), C = {carry from MSB} (integer)
    Exceptions:     Integer or floating overflow, floating
                    underflow, reserved operand
    Opcodes:        80    ADDB2    Add byte 2 operand
                    81    ADDB3    Add byte 3 operand
                    A0    ADDW2    Add word 2 operand
                    A1    ADDW3    Add word 3 operand
                    C0    ADDL2    Add long 2 operand
                    C1    ADDL3    Add long 3 operand
                    40    ADDF2    Add F_floating 2 operand
                    41    ADDF3    Add F_floating 3 operand
                    60    ADDD2    Add D_floating 2 operand
                    61    ADDD3    Add D_floating 3 operand
                    40FD  ADDG2    Add G_floating 2 operand
                    41FD  ADDG3    Add G_floating 3 operand
                    60FD  ADDH2    Add H_floating 2 operand
                    61FD  ADDH3    Add H_floating 3 operand