Intr procedure

  DECLARATION: Intr(IntNo : Byte; var Regs : Registers);

      PURPOSE:  Executes a specified software interrupt

         UNIT:  DOS

      REMARKS:  IntNo is the software interrupt (0..255) requested.
                Registers is a record defined in the DOS unit as:

                Type
                   Registers = Record
                                 Case Integer of
                                    0 : (AX,BX,CX,DX,BP,SI,DI,DS,ES
                                         Flags : Word);
                                    1 : (AL,AH,BL,BH,CL,CH,DL,DH : Byte);
                               End;

                Before executing the requested interrupt, Intr loads the
                8086 CPU AX, BX, CX, DX, BP, SI, DI, DS, and ES registers
                from the Regs record.  After executing the interrupt, the
                contents of the AX, BX, CX, DX, BP, SI, DI, DS, ES, and
                Flags registers are stored back into the Regs record.