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[f-cpu] Erin32 Calling Convention

Hello from Southern Mississippi:
    Subroutine Calls are initiated with a simple JST (Jump and Store Return) instruction.  This is the mechanism:
                            LDA    Money    To pass an argument
                            JST     DO
                            CMP    Lost
                            DO      PZE        Initially Zero
                            ADD    Anything
    My design executes the LDA and JST in parallel. The JST stores the incremented PC in DO, and executes the instruction DO+1.
Upon completion of  SUBR Called (DO), an Indirect Jump is executed, JMPN. 
                            JMPN    DO    Return to JST + 1
    Priority Interrupts are handled in the same manner; as an Interrupt is nothing more that a JST
    I don't have to consider what Register does what, as I don't have any.  My registers are in Operand (Local Memory) .  I potentially have 256K of Registers.
Have a good day
Richard Hartney
Erin Greene & Assiciates
Business Information Management Systems