! *** 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
    
    
    ! 
    !  Thread Environment Block Definitions
    ! 
      DECLARE LONG CONSTANT TEB$M_ASTACT = x'00000001'
      DECLARE LONG CONSTANT TEB$M_ASTEN = x'00000002'
      DECLARE LONG CONSTANT TEB$S_TEB = 144
      record TEB
         BASIC$QUADWORD TEB$PQ_FLINK        !  Forward queue link
         BASIC$QUADWORD TEB$PQ_BLINK        !  Backward queue link
         WORD TEB$W_SIZE                    !  Size of TEB, in bytes
         BYTE TEB$B_VERSION                 !  Version number for TEB
         BYTE TEB$B_TYPE                    !  Structure type code for TEB
         BYTE TEB$b_reserved_2 ( 1 to 4 )      !  Reserved to DECthreads
         BASIC$QUADWORD TEB$Q_SEQUENCE      !  Thread sequence number
         BASIC$QUADWORD TEB$q_reserved_3 ( 1 to 2 )  !  Reserved to DECthreads
         BASIC$QUADWORD TEB$PQ_PER_KT_AREA  !  Address of per kernel thread area
         BASIC$QUADWORD TEB$PQ_STACK_BASE   !  Address of first usable byte in stack
         BASIC$QUADWORD TEB$PQ_STACK_RESERVE  !  Address of first byte in reserve area
         BASIC$QUADWORD TEB$PQ_STACK_YELLOW  !  Address of first byte in yellow area
         BASIC$QUADWORD TEB$PQ_STACK_GUARD  !  Address of first byte in guard area
         BASIC$QUADWORD TEB$Q_STACK_SIZE    !  Total stack allocation (green+reserve+yellow+red)
         BASIC$QUADWORD TEB$PQ_TSD_VALUES   !  Address of thread-specific data array
         LONG TEB$L_TSD_COUNT               !  Count of thread-specific data values
         LONG TEB$L_CANCEL_FLAGS            !  cancel flags
         LONG TEB$L_CANCEL_COUNT            !  CMA alert scope nesting count
         group TEB$R_FILL_27_
            variant
               case
                  LONG TEB$L_THREAD_FLAGS   !  thread flags
               case
                  group TEB$R_FILL_28_
                      !  there's a user mode AST active
                      !  use mode ASTs are enabled
                     BYTE ASTACT_bits   ! COMMENT ADDED BY SDL - ASTACT_bits contains bits ASTACT through FILL_29_
                  end group TEB$R_FILL_28_
            end variant
         end group TEB$R_FILL_27_
         LONG TEB$L_THD_ERRNO               !  Per-thread errno value
         LONG TEB$l_reserved_4              !  Reserved to DECthreads
         BASIC$QUADWORD TEB$PQ_STACK_HIWATER  !  Lowest known SP address
         LONG TEB$L_HOME_RAD                !  Thread's home RAD
         LONG TEB$L_RAD_SAFE                !  Scratch: written by Tru64 UNIX
      end record TEB
    
      DECLARE LONG CONSTANT TEB$K_LENGTH = 144  !  Length of TEB 
      DECLARE LONG CONSTANT TEB$C_LENGTH = 144  !  Length of TEB 
      DECLARE LONG CONSTANT TEB$C_TSD_KEY_SSPI = 1  !  TSD key value reserved for SSPI