DXADD(3)

SYNOPSIS
SUBROUTINE DXADD (X, IX, Y, IY, Z, IZ, IERROR)

NAME
dxadd - To provide double-precision floating-point arithmetic with an extended exponent range.

LIBRARY
SLATEC

CATEGORY
A3D

TYPE
DOUBLE PRECISION (XADD-S, DXADD-D)

KEYWORDS
EXTENDED-RANGE DOUBLE-PRECISION ARITHMETIC

AUTHOR
Lozier, Daniel W., (National Bureau of Standards) Smith, John M., (NBS and George Mason University)

DESCRIPTION
DOUBLE PRECISION X, Y, Z INTEGER IX, IY, IZ FORMS THE EXTENDED-RANGE SUM (Z,IZ) = (X,IX) + (Y,IY). (Z,IZ) IS ADJUSTED BEFORE RETURNING. THE INPUT OPERANDS NEED NOT BE IN ADJUSTED FORM, BUT THEIR PRINCIPAL PARTS MUST SATISFY RADIX**(-2L).LE.ABS(X).LE.RADIX**(2L), RADIX**(-2L).LE.ABS(Y).LE.RADIX**(2L).

SEE ALSO
DXSET

REFERENCES
(NONE)

ROUTINES CALLED
DXADJ

COMMON BLOCKS
DXBLK2

REVISION HISTORY (YYMMDD)
820712 DATE WRITTEN
881020 Revised to meet SLATEC CML recommendations. (DWL and JMS)
901019 Revisions to prologue. (DWL and WRB)
901106 Changed all specific intrinsics to generic. (WRB) Corrected order of sections in prologue and added TYPE section. (WRB)
920127 Revised PURPOSE section of prologue. (DWL)