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Annotation of researchv10no/cmd/view2d/num/sscal.f, revision 1.1.1.1

1.1       root        1:       subroutine sscal(n,sa,sx,incx)
                      2: c
                      3: c     scales a vector by a constant.
                      4: c     uses unrolled loops for increment equal to 1.
                      5: c     jack dongarra, linpack, 3/11/78.
                      6: c
                      7:       real sa,sx(1)
                      8:       integer i,incx,m,mp1,n,nincx
                      9: c
                     10:       if(n.le.0)return
                     11:       if(incx.eq.1)go to 20
                     12: c
                     13: c        code for increment not equal to 1
                     14: c
                     15:       nincx = n*incx
                     16:       do 10 i = 1,nincx,incx
                     17:         sx(i) = sa*sx(i)
                     18:    10 continue
                     19:       return
                     20: c
                     21: c        code for increment equal to 1
                     22: c
                     23: c
                     24: c        clean-up loop
                     25: c
                     26:    20 m = mod(n,5)
                     27:       if( m .eq. 0 ) go to 40
                     28:       do 30 i = 1,m
                     29:         sx(i) = sa*sx(i)
                     30:    30 continue
                     31:       if( n .lt. 5 ) return
                     32:    40 mp1 = m + 1
                     33:       do 50 i = mp1,n,5
                     34:         sx(i) = sa*sx(i)
                     35:         sx(i + 1) = sa*sx(i + 1)
                     36:         sx(i + 2) = sa*sx(i + 2)
                     37:         sx(i + 3) = sa*sx(i + 3)
                     38:         sx(i + 4) = sa*sx(i + 4)
                     39:    50 continue
                     40:       return
                     41:       end

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