subroutine r9gaml (xmin, xmax)
c april 1977 version.  w. fullerton, c3, los alamos scientific lab.
c
c calculate the minimum and maximum legal bounds for x in gamma(x).
c xmin and xmax are not the only bounds, but they are the only non-
c trivial ones to calculate.
c
c             output arguments --
c xmin   minimum legal value of x in gamma(x).  any smaller value of
c        x might result in underflow.
c xmax   maximum legal value of x in gamma(x).  any larger value will
c        cause overflow.
c
      external alog, r1mach
c
      alnsml = alog(r1mach(1))
      xmin = -alnsml
      do 10 i=1,10
        xold = xmin
        xln = alog(xmin)
        xmin = xmin - xmin*((xmin+0.5)*xln - xmin - 0.2258 + alnsml)
     1    / (xmin*xln + 0.5)
        if (abs(xmin-xold).lt.0.005) go to 20
 10   continue
      call seteru (27hr9gaml  unable to find xmin, 27, 1, 2)
c
 20   xmin = -xmin + 0.01
c
      alnbig = alog(r1mach(2))
      xmax = alnbig
      do 30 i=1,10
        xold = xmax
        xln = alog(xmax)
        xmax = xmax - xmax*((xmax-0.5)*xln - xmax + 0.9189 - alnbig)
     1    / (xmax*xln - 0.5)
        if (abs(xmax-xold).lt.0.005) go to 40
 30   continue
      call seteru (27hr9gaml  unable to find xmax, 27, 2, 2)
c
 40   xmax = xmax - 0.01
      xmin = amax1 (xmin, -xmax+1.)
c
      return
      end