OpenLibm/slatec/i1merg.f
Viral B. Shah c977aa998f Add Makefile.extras to build libopenlibm-extras.
Replace amos with slatec
2012-12-31 16:37:05 -05:00

60 lines
1.6 KiB
Fortran

*DECK I1MERG
SUBROUTINE I1MERG (ICOS, I1, M1, I2, M2, I3)
C***BEGIN PROLOGUE I1MERG
C***SUBSIDIARY
C***PURPOSE Merge two strings of ascending integers.
C***LIBRARY SLATEC
C***TYPE INTEGER (S1MERG-S, D1MERG-D, C1MERG-C, I1MERG-I)
C***AUTHOR Boland, W. Robert, (LANL)
C Clemens, Reginald, (PLK)
C***DESCRIPTION
C
C This subroutine merges two ascending strings of integers in the
C array ICOS. The first string is of length M1 and starts at
C ICOS(I1+1). The second string is of length M2 and starts at
C ICOS(I2+1). The merged string goes into ICOS(I3+1).
C
C***ROUTINES CALLED ICOPY
C***REVISION HISTORY (YYMMDD)
C 920202 DATE WRITTEN
C***END PROLOGUE I1MERG
INTEGER I1, I2, I3, M1, M2
REAL ICOS(*)
C
INTEGER J1, J2, J3
C
C***FIRST EXECUTABLE STATEMENT I1MERG
IF (M1.EQ.0 .AND. M2.EQ.0) RETURN
C
IF (M1.EQ.0 .AND. M2.NE.0) THEN
CALL ICOPY (M2, ICOS(I2+1), 1, ICOS(I3+1), 1)
RETURN
ENDIF
C
IF (M1.NE.0 .AND. M2.EQ.0) THEN
CALL ICOPY (M1, ICOS(I1+1), 1, ICOS(I3+1), 1)
RETURN
ENDIF
C
J1 = 1
J2 = 1
J3 = 1
C
10 IF (ICOS(I1+J1) .LE. ICOS(I2+J2)) THEN
ICOS(I3+J3) = ICOS(I1+J1)
J1 = J1+1
IF (J1 .GT. M1) THEN
CALL ICOPY (M2-J2+1, ICOS(I2+J2), 1, ICOS(I3+J3+1), 1)
RETURN
ENDIF
ELSE
ICOS(I3+J3) = ICOS(I2+J2)
J2 = J2+1
IF (J2 .GT. M2) THEN
CALL ICOPY (M1-J1+1, ICOS(I1+J1), 1, ICOS(I3+J3+1), 1)
RETURN
ENDIF
ENDIF
J3 = J3+1
GO TO 10
END