Routine:        Regsv   
Function:       Saves all the registers to the stack
Called by:      Almvis, Calib, Divide, Err, Input, Meas, Mult, Print, Read, Recip, Sub, Visc.
Calls:          None
Entry:          All
Exit:           All
Preserved:      All


REGSV   EX      (SP),IX
        PUSH    IY
        PUSH    AF
        PUSH    BC
        PUSH    DE
        PUSH    HL
        PUSH    IX
; Restore subroutine return address.
        RET