!>
!> SLAGS2 computes 2-by-2 orthogonal matrices U, V and Q, such
!> that if ( UPPER ) then
!>
!>           U**T *A*Q = U**T *( A1 A2 )*Q = ( x  0  )
!>                             ( 0  A3 )     ( x  x  )
!> and
!>           V**T*B*Q = V**T *( B1 B2 )*Q = ( x  0  )
!>                            ( 0  B3 )     ( x  x  )
!>
!> or if ( .NOT.UPPER ) then
!>
!>           U**T *A*Q = U**T *( A1 0  )*Q = ( x  x  )
!>                             ( A2 A3 )     ( 0  x  )
!> and
!>           V**T*B*Q = V**T*( B1 0  )*Q = ( x  x  )
!>                           ( B2 B3 )     ( 0  x  )
!>
!> The rows of the transformed A and B are parallel, where
!>
!>   U = (  CSU  SNU ), V = (  CSV SNV ), Q = (  CSQ   SNQ )
!>       ( -SNU  CSU )      ( -SNV CSV )      ( -SNQ   CSQ )
!>
!> Z**T denotes the transpose of Z.
!>
!> 

UPPER

!>          UPPER is LOGICAL
!>          = .TRUE.: the input matrices A and B are upper triangular.
!>          = .FALSE.: the input matrices A and B are lower triangular.
!> 

A1

!>          A1 is REAL
!> 

A2

!>          A2 is REAL
!> 

A3

!>          A3 is REAL
!>          On entry, A1, A2 and A3 are elements of the input 2-by-2
!>          upper (lower) triangular matrix A.
!> 

B1

!>          B1 is REAL
!> 

B2

!>          B2 is REAL
!> 

B3

!>          B3 is REAL
!>          On entry, B1, B2 and B3 are elements of the input 2-by-2
!>          upper (lower) triangular matrix B.
!> 

CSU

!>          CSU is REAL
!> 

SNU

!>          SNU is REAL
!>          The desired orthogonal matrix U.
!> 

CSV

!>          CSV is REAL
!> 

SNV

!>          SNV is REAL
!>          The desired orthogonal matrix V.
!> 

CSQ

!>          CSQ is REAL
!> 

SNQ

!>          SNQ is REAL
!>          The desired orthogonal matrix Q.
!> 

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