SLATEC Routines --- MPADD2 ---

*DECK MPADD2
      SUBROUTINE MPADD2 (X, Y, Z, Y1, TRUNC)
C***BEGIN PROLOGUE  MPADD2
C***SUBSIDIARY
C***PURPOSE  Subsidiary to DQDOTA and DQDOTI
C***LIBRARY   SLATEC
C***TYPE      ALL (MPADD2-A)
C***AUTHOR  (UNKNOWN)
C***DESCRIPTION
C
C  Called by MPADD, MPSUB etc.
C  X, Y and Z are MP numbers, Y1 and TRUNC are integers.
C  To force call by reference rather than value/result, Y1 is
C  declared as an array, but only Y1(1) is ever used.
C  Sets Z = X + Y1(1)*ABS(Y), where Y1(1) = +- Y(1).
C  If TRUNC .EQ. 0, R*-rounding is used;  otherwise, truncation.
C  R*-rounding is defined in the Kuki and Cody reference.
C
C  The arguments X(*), Y(*), and Z(*) are all INTEGER arrays of size
C  30.  See the comments in the routine MPBLAS for the reason for this
C  choice.
C
C***SEE ALSO  DQDOTA, DQDOTI, MPBLAS
C***REFERENCES  H. Kuki and W. J. Cody, A statistical study of floating
C                 point number systems, Communications of the ACM 16, 4
C                 (April 1973), pp. 223-230.
C               R. P. Brent, On the precision attainable with various
C                 floating-point number systems, IEEE Transactions on
C                 Computers C-22, 6 (June 1973), pp. 601-607.
C               R. P. Brent, A Fortran multiple-precision arithmetic
C                 package, ACM Transactions on Mathematical Software 4,
C                 1 (March 1978), pp. 57-70.
C               R. P. Brent, MP, a Fortran multiple-precision arithmetic
C                 package, Algorithm 524, ACM Transactions on Mathema-
C                 tical Software 4, 1 (March 1978), pp. 71-81.
C***ROUTINES CALLED  MPADD3, MPCHK, MPERR, MPNZR, MPSTR
C***COMMON BLOCKS    MPCOM
C***REVISION HISTORY  (YYMMDD)
C   791001  DATE WRITTEN
C   ??????  Modified for use with BLAS.  Blank COMMON changed to named
C           COMMON.  R given dimension 12.
C   890531  Changed all specific intrinsics to generic.  (WRB)
C   891214  Prologue converted to Version 4.0 format.  (BAB)
C   900402  Added TYPE section.  (WRB)
C   920528  Added a REFERENCES section revised.  (WRB)
C   930124  Increased Array size in MPCON for SUN -r8.  (RWC)
C***END PROLOGUE  MPADD2