! *** 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
    
    
    ! 
    !  Operating System Specific Data area offset definitions for the IA64
    !  VMS calling standard.
    ! 
    ! 
    !  Spill Data triple
    ! 
      DECLARE LONG CONSTANT OSSD$M_REG = x'0000001F'
      DECLARE LONG CONSTANT OSSD$M_MBZ_5_7 = x'000000E0'
      DECLARE LONG CONSTANT OSSD$M_TREG = x'00007F00'
      DECLARE LONG CONSTANT OSSD$M_MBZ_15 = x'00008000'
      DECLARE LONG CONSTANT OSSD$S_OSSD_SPILL_DATA = 3
      record OSSD_SPILL_DATA
         group OSSD$R_SPILL_OVERLAY
            variant
               case
                  group OSSD$R_SPILL_STRUCT_1
                      !  Static general register being saved
                      !  MBZ
                      !  Target register for save or zero for restore
                      !  MBZ
                     WORD REG_bits   ! COMMENT ADDED BY SDL - REG_bits contains bits REG through MBZ_15
                  end group OSSD$R_SPILL_STRUCT_1
               case
                  group OSSD$R_SPILL_STRUCT_2
                     BYTE OSSD$B_REG_BYTE   !  Byte containing 5-bit REG field
                     BYTE OSSD$B_TREG_BYTE  !  Byte containing 7-bit TREG field
                  end group OSSD$R_SPILL_STRUCT_2
            end variant
         end group OSSD$R_SPILL_OVERLAY
         BYTE OSSD$T_T ( 1 to 1 )              !  ULEB128 slot offset to save/restore instruction
      end record OSSD_SPILL_DATA
    
    ! 
    !  OSSD layout for general and caller spill register information segments
    ! 
      DECLARE LONG CONSTANT OSSD$M_TYPE = x'00007FFF'
      DECLARE LONG CONSTANT OSSD$K_GENERAL_INFO = 1  !  General info (always one quadword)
      DECLARE LONG CONSTANT OSSD$K_CALL_SPILL_INFO = 2  !  Caller spill info (variable length)
      DECLARE LONG CONSTANT OSSD$K_CONTEXT_INFO = 3  !  Context info (always one quadword)
      DECLARE LONG CONSTANT OSSD$M_S = x'00008000'
      DECLARE LONG CONSTANT OSSD$M_EXCEPTION_MODE = x'00070000'
      DECLARE LONG CONSTANT OSSD$K_EXC_MODE_SIGNAL = 0  !  Signal
      DECLARE LONG CONSTANT OSSD$K_EXC_MODE_SIGNAL_ALL = 1  !  Signal all
      DECLARE LONG CONSTANT OSSD$K_EXC_MODE_SIGNAL_SILENT = 2  !  Signal silent
      DECLARE LONG CONSTANT OSSD$K_EXC_MODE_FULL_IEEE = 3  !  Signal full IEEE
      DECLARE LONG CONSTANT OSSD$K_EXC_MODE_CALLER = 4  !  Use caller's mode
      DECLARE LONG CONSTANT OSSD$M_TARGET_INVO = x'00080000'
      DECLARE LONG CONSTANT OSSD$M_BASE_FRAME = x'00100000'
      DECLARE LONG CONSTANT OSSD$M_HANDLER_REINVOKABLE = x'00200000'
      DECLARE LONG CONSTANT OSSD$M_AST_FRAME = x'00400000'
      DECLARE LONG CONSTANT OSSD$M_EXCEPTION_FRAME = x'00800000'
      DECLARE LONG CONSTANT OSSD$M_TIE_FRAME = x'01000000'
      DECLARE LONG CONSTANT OSSD$M_BOTTOM_OF_STACK = x'02000000'
      DECLARE LONG CONSTANT OSSD$M_HANDLER_DATA_VALID = x'04000000'
      DECLARE LONG CONSTANT OSSD$M_SS_DISPATCH_FRAME = x'08000000'
      DECLARE LONG CONSTANT OSSD$M_KP_START_FRAME = x'10000000'
      DECLARE LONG CONSTANT OSSD$M_FRAMELESS_HELPER = x'20000000'
      DECLARE LONG CONSTANT OSSD$M_MBZ_30_63 = x'00000000'
      DECLARE LONG CONSTANT OSSD$K_GENERAL_INFO_LENGTH = 8  !  Size of general data segment
      DECLARE LONG CONSTANT OSSD$M_CONTEXT_TYPE = x'00FF0000'
      DECLARE LONG CONSTANT OSSD$K_CTX_TYPED = 0  !  A VMS typed data structure
      DECLARE LONG CONSTANT OSSD$K_CTX_CHFCTX = 1  !  A CHFCTX block
      DECLARE LONG CONSTANT OSSD$M_CONTEXT_GR = x'FF000000'
      DECLARE LONG CONSTANT OSSD$M_CONTEXT_OFFSET = x'00000000'
      DECLARE LONG CONSTANT OSSD$M_CONTEXT_HINT = x'00000000'
      DECLARE LONG CONSTANT OSSD$K_HINT_EXCEPTION = 1  !    Exception dispatcher
      DECLARE LONG CONSTANT OSSD$K_HINT_SS = 2  !    System Service dispatcher
      DECLARE LONG CONSTANT OSSD$K_HINT_AST = 3  !    AST dispatcher
      DECLARE LONG CONSTANT OSSD$K_HINT_KP_START = 4  !    KP_START frame
      DECLARE LONG CONSTANT OSSD$K_CONTEXT_INFO_LENGTH = 8  !  Size of context info segment
      DECLARE LONG CONSTANT OSSD$S_OSSDDEF = 8
      record OSSDDEF
         group OSSD$R_DATA_OVERLAY
            variant
               case
                  BASIC$QUADWORD OSSD$Q_GENERAL_INFO_SEGMENT  !  Entire general info segment
               case
                  group OSSD$R_GENERAL_STRUCT
                      !  OSSD segment type
                      !  Continuation marker
                      !  Desired exception-reporting behavior
                      !  Invoke handler when unwind target
                      !  Logical base frame of stack
                      !  Handler may be invoked when already active
                      !  AST dispatch frame
                      !  Exception dispatch frame
                      !  Frame created by Translated Image Executive
                      !  End of call stack (no predecessors)
                      !  Exception handler data field exists in unwind info
                      !  System Service dispatch frame
                      !  Used to tag EXE$KP_START
                      !  Tags code executing in context of another routine whose IP is in B0
                      !  MBZ
                     BYTE TYPE_bits ( 8 )   ! COMMENT ADDED BY SDL - TYPE_bits contains bits TYPE through MBZ_30_63
                  end group OSSD$R_GENERAL_STRUCT
               case
                  group OSSD$R_SPILL_STRUCT_3
                     WORD OSSD$W_FILL_3     !  Overlays segment type and continuation marker
                     WORD OSSD$W_LENGTH     !  # quadwords in this segment
                     OSSD_SPILL_DATA OSSD$T_SPILL_DATA  !  Start of first spill data triple
                  end group OSSD$R_SPILL_STRUCT_3
               case
                  BASIC$QUADWORD OSSD$Q_CONTEXT_INFO_SEGMENT  !  Entire context info segment
               case
                  group OSSD$R_CONTEXT_INFO_STRUCT
                     WORD OSSD$W_FILL_4     !  Overlays segment type and continuation marker
                      !  Type of context block described
                      !  GR containing pointer to context block
                      !  Offset (in octawords) from SP, or GR
                      !  Hint as to purpose of context block
    !  Hints:  (0 = no hint)
                     BYTE CONTEXT_TYPE_bits ( 6 )   ! COMMENT ADDED BY SDL - CONTEXT_TYPE_bits contains bits CONTEXT_TYPE through  &
 ! CONTEXT_HINT
                  end group OSSD$R_CONTEXT_INFO_STRUCT
            end variant
         end group OSSD$R_DATA_OVERLAY
      end record OSSDDEF
    
    !   The following macro can be used in IAS code to create a context info OSSD
    !   segment.  Cut and paste to your IAS module
    ! 
    ! #define __CONTEXT_OSSD(type,gr,offset,hint) \
    ! 	.vms_ossd ((hint) << OSSD$V_CONTEXT_HINT) | \
    ! 		  (((offset) ? 0xFFFFFF) << OSSD$V_CONTEXT_OFFSET) | \
    ! 		  ((gr) << OSSD$V_CONTEXT_GR) | \
    ! 		  ((type) << OSSD$V_CONTEXT_TYPE) | OSSD$K_CONTEXT_INFO
    !