On 28 Jul 2004 at 12:58, I wrote:
  I'll check my March 1977 HP Journal that
introduces the E-series, but
 as far as I know, all MX machines had floating point routines built in.  
Page 23 of that issue says under "Specifications:"
  "BASE SET INSTRUCTIONS: 128 standard instructions including [...]
   high-speed floating point."
                                      -- Dave