1      SUBROUTINE DTREVC( SIDE, HOWMNY, SELECT, N, T, LDT, VL, LDVL, VR,
2     $                   LDVR, MM, M, WORK, INFO )
3      DOUBLE PRECISION   T( LDT, * ), VL( LDVL, * ), VR( LDVR, * ),
4     $                   WORK( * )
5      DOUBLE PRECISION   X( 2, 2 )
6      CALL DLALN2( .FALSE., 1, 1, SMIN, ONE, T( J, J ),
7     $                            ZERO, X, 2, SCALE, XNORM, IERR )
8      CALL DSCAL( KI, SCALE, WORK( 1+N ), 1 )
9      DO 90 J = KI - 2, 1, -1
10      IF( J.GT.JNXT )
11     $               GO TO 90
12      JNXT = J - 1
13      IF( J.GT.1 ) THEN
14          IF( T( J, J-1 ).NE.ZERO ) THEN
15              IF( WORK( J ).GT.BIGNUM / XNORM ) THEN
16                  X( 1, 1 ) = X( 1, 1 ) / XNORM
17              END IF
18          END IF
19          CALL DLALN2( .FALSE., 2, 2, SMIN, ONE,
20     $                            T( J-1, J-1 ), LDT, ONE, ONE,
21     $                            XNORM, IERR )
22          CALL DAXPY( J-2, -X( 1, 1 ), T( 1, J-1 ), 1,
23     $                           WORK( 1+N ), 1 )
24          CALL DAXPY( J-2, -X( 2, 2 ), T( 1, J ), 1,
25     $                           WORK( 1+N2 ), 1 )
26      END IF
27   90          CONTINUE
28      END
29