! *** PREDECLARED TYPES
     
      %IF %DECLARED ( %BASIC$QUADWORD_DECLARED ) = 0 %THEN
         RECORD BASIC$QUADWORD
            LONG FILL ( 2 )
         END RECORD
         %LET %BASIC$QUADWORD_DECLARED = 1
      %END %IF
     
      %IF %DECLARED ( %BASIC$OCTAWORD_DECLARED ) = 0 %THEN
         RECORD BASIC$OCTAWORD
            LONG FILL ( 4 )
         END RECORD
         %LET %BASIC$OCTAWORD_DECLARED = 1
      %END %IF
     
      %IF %DECLARED ( %BASIC$HFLOAT_AXP_DECLARED ) = 0 %THEN
         RECORD BASIC$HFLOAT_AXP
            LONG FILL ( 4 )
         END RECORD
         %LET %BASIC$HFLOAT_AXP_DECLARED = 1
      %END %IF
     
      %IF %DECLARED ( %BASIC$F_FLOATING_COMPLEX_DECL ) = 0 %THEN
         RECORD BASIC$F_FLOATING_COMPLEX
            SINGLE REAL_PART
            SINGLE IMAGINARY_PART
         END RECORD
         %LET %BASIC$F_FLOATING_COMPLEX_DECL = 1
      %END %IF
     
      %IF %DECLARED ( %BASIC$D_FLOATING_COMPLEX_DECL ) = 0 %THEN
         RECORD BASIC$D_FLOATING_COMPLEX
            DOUBLE REAL_PART
            DOUBLE IMAGINARY_PART
         END RECORD
         %LET %BASIC$D_FLOATING_COMPLEX_DECL = 1
      %END %IF
     
      %IF %DECLARED ( %BASIC$G_FLOATING_COMPLEX_DECL ) = 0 %THEN
         RECORD BASIC$G_FLOATING_COMPLEX
            GFLOAT REAL_PART
            GFLOAT IMAGINARY_PART
         END RECORD
         %LET %BASIC$G_FLOATING_COMPLEX_DECL = 1
      %END %IF
     
      %IF %DECLARED ( %BASIC$H_FLOAT_AXP_CMPLX_DCL ) = 0 %THEN
         RECORD BASIC$H_FLOATING_COMPLEX_AXP
            BASIC$HFLOAT_AXP REAL_PART
            BASIC$HFLOAT_AXP IMAGINARY_PART
         END RECORD
         %LET %BASIC$H_FLOAT_AXP_CMPLX_DCL = 1
      %END %IF
    
    
      DECLARE LONG CONSTANT LIB$K_PROC_VALUE_NULL = 0
      DECLARE LONG CONSTANT LIB$K_INVO_HANDLE_NULL = 0
      DECLARE LONG CONSTANT LIBICB$K_INVO_HANDLE_SIZE = 4
      DECLARE LONG CONSTANT LIBICB$K_INVO_CONTEXT_VERSION = 1
    ! 
      DECLARE LONG CONSTANT LIBICB$M_FFLAGS_BITS = x'00FFFFFF'
      DECLARE LONG CONSTANT LIBICB$M_EXCEPTION_FRAME = x'00000001'
      DECLARE LONG CONSTANT LIBICB$M_AST_FRAME = x'00000002'
      DECLARE LONG CONSTANT LIBICB$M_BOTTOM_OF_STACK = x'00000004'
      DECLARE LONG CONSTANT LIBICB$M_BASE_FRAME = x'00000008'
      DECLARE LONG CONSTANT LIBICB$K_INVO_CONTEXT_BLK_SIZE = 544
      DECLARE LONG CONSTANT LIBICB$S_INVO_CONTEXT_BLK = 544
      record INVO_CONTEXT_BLK
    !  The first quadword contains:
    ! 
    !      o  The length of the structure in bytes (a longword field)
    !      o  The frame flags (a 3 byte field of bits)
    !      o  The version number (a 1 byte field)
    !  
         group LIBICB$R_HDR
            variant
               case
                  BASIC$QUADWORD LIBICB$Q_HDR_QUAD
               case
                  group LIBICB$R_HDR_DESC
                     LONG LIBICB$L_CONTEXT_LENGTH
                     group LIBICB$R_FRAMEFLAGS
                        variant
                        case
                           LONG FFLAGS_BITS_bits   ! COMMENT ADDED BY SDL - FFLAGS_BITS_bits contains bits FFLAGS_BITS through  &
 ! FFLAGS_BITS
                        case
                           group LIBICB$R_FFLAGS_DESC
                              BYTE EXCEPTION_FRAME_bits   ! COMMENT ADDED BY SDL - EXCEPTION_FRAME_bits contains bits  &
 ! EXCEPTION_FRAME through FILL_0_
                           end group LIBICB$R_FFLAGS_DESC
                        end variant
                     end group LIBICB$R_FRAMEFLAGS
                     BYTE LIBICB$B_BLOCK_VERSION
                  end group LIBICB$R_HDR_DESC
            end variant
         end group LIBICB$R_HDR
    ! 
    !  The address of the procedure descriptor for the procedure.
    ! 
         BASIC$QUADWORD LIBICB$PH_PROCEDURE_DESCRIPTOR
    ! 
    !  The current PC of a given procedure invocation.
    !  
         BASIC$QUADWORD LIBICB$Q_PROGRAM_COUNTER
    ! 
    !  The current PS of a given procedure invocation.
    ! 
         BASIC$QUADWORD LIBICB$Q_PROCESSOR_STATUS
    ! 
    !  The register contents areas. 31 for scalars, 31 for float.
    !      
         BASIC$QUADWORD LIBICB$Q_IREG ( 30 )
         BASIC$QUADWORD LIBICB$Q_FREG ( 30 )
    ! 
    !  The following is an "internal" area that's reserved for use by
    !  the operating system. It's size may vary over time.
    !      
         group LIBICB$R_SYSTEM_SPECIFIC
            variant
               case
                  BASIC$QUADWORD LIBICB$PH_CHFCTX_ADDR
               case
                  BASIC$QUADWORD LIBICB$Q_SYSTEM_DEFINED ( 1 )
            end variant
         end group LIBICB$R_SYSTEM_SPECIFIC
    ! 
    !  Align to octaword.
    !  
         STRING LIBICB$T_ALIGN = 0
      end record INVO_CONTEXT_BLK