PUSH_REGS   MACRO  REG1, REG2, REG3, REG4

        NUM_REGS = 1

        PUSH REG1

        IFNB <REG2>
        NUM_REGS = NUM_REGS + 1
        PUSH REG2
        ENDIF

        IFNB <REG3>
        NUM_REGS = NUM_REGS + 1
        PUSH REG3
        ENDIF

        IFNB <REG4>
        NUM_REGS = NUM_REGS + 1
        PUSH REG4
        ENDIF

        PUSH BP

        MOV  BP, SP

        ARG_BASE EQU BP + 4 + (2 * NUM_REGS)

        ENDM