SUBROUTINE L1_EXTRACT_EXPOS_AND_L0(CRATE_HEADER,
     &                                   CURRENT_TRG,
     &                                   UNITS,
     &                                   GIGAS )
C----------------------------------------------------------------------
C-
C-   Purpose and Methods : Extract the Exposition and Level 0 scaler for a
C-     particular Specific Trigger from the Data Block.
C-
C-   Inputs  : CRATE_HEADER     The first word of the Level 1 Data Block Crate
C-                              Header. Cf. GZFIND_CRATE().
C-             CURRENT_TRG      The number of the Specific Trigger to extract
C-                              data about.
C-   Outputs : UNITS            The scaler MOD 2**30
C-             GIGAS            The scaler DIV 2**30
C-   Controls: none
C-
C-      NOTE: The EXPOS_AND_L0 value is calculated as:
C-            EXPOS - EXPOS_AND_NOT_L0
C-            Note that this requires 5-byte arithmetic.
C
C-   Created  24-MAR-1992   Philippe Laurens, Steven Klocek
C-
C----------------------------------------------------------------------
      IMPLICIT NONE
      INCLUDE 'LEVEL1_LOOKUP.PARAMS'
      INCLUDE 'LEVEL1_CAL_TRIG.PARAMS'
      INCLUDE 'LEVEL1_FRAMEWORK.PARAMS'
      INCLUDE 'LEVEL1_TRIGGER_DATA_BLOCK.INC'
C
      INTEGER CRATE_HEADER
      INTEGER CURRENT_TRG
      INTEGER UNITS
      INTEGER GIGAS
C
      INTEGER NOT_L0_UNITS
      INTEGER NOT_L0_GIGAS
      INTEGER EXPOS_UNITS
      INTEGER EXPOS_GIGAS
C
      CALL L1_EXTRACT_5BYTE_SCALER(CRATE_HEADER,
     &          SP_TRG_SCALERS+ 2 * SCALER_L * CURRENT_TRG + SCALER_L,
     &          EXPOS_UNITS,
     &          EXPOS_GIGAS )
C**
C       An Expos and Not Level 0 scaler does not exist yet
C 
C      CALL L1_EXTRACT_5BYTE_SCALER(CRATE_HEADER,
C     &          XXXXX, 
C     &          NOT_L0_UNITS,
C     &          NOT_L0_GIGAS )
C
      NOT_L0_UNITS = 0
      NOT_L0_GIGAS = 0
C**
      UNITS = EXPOS_UNITS - NOT_L0_UNITS
      GIGAS = EXPOS_GIGAS - NOT_L0_GIGAS
      IF (UNITS .LT. 0) THEN
        UNITS = UNITS + 2**30
        GIGAS = GIGAS - 1
      ENDIF
C
C----------------------------------------------------------------------
  999 RETURN
      END