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"Deller, Steve" <[log in to unmask]>
Reply To:
Deller, Steve
Fri, 10 Aug 2001 07:03:50 -0700
text/plain (77 lines)
> -----Original Message-----
> From: prabhath rao [mailto:[log in to unmask]]
> Sent: Friday, August 10, 2001 9:01 AM
> To: [log in to unmask]
> Subject: converting from 64 bit mode to 32 bit mode
> Hello,
> I have an assignment, in which i have to port GNAT ada 95
> code running on
> Tru64 unix, which runs in 64 bit mode to GNAT ada 95(which
> outputs 32 bit
> mode executable) on HP platform. I would like to know the complexity
> involved and any reference manual is there which can ease my job
> Best regards
> Prabhath


Amount of effort depends on:
  1. How much the application depends on
     64-bit primitives (integers, addresses, etc.)
     That can be: "a lot", "some", "a little" or "not at all".
     Note *depend*, not "unintentionally used".
     Each case will have to be addressed by hand (typically).
     Solutions can be quite simple to quite difficult.
  2. How much the application depends on
     Tru64 Unix operating system "extensions" to
     standard unix interfaces, i.e. OS support that
     is not in HP-UX.
     Each case has to be addressed by hand.
     Solutions can be straight-forward to
     quite difficult.  Solutions are rarely simple.
  3. Does the data plus code exceed 1GB (the HP-UX limit)?
     If so, solutions are typically quite complex.

A rough order of magnitude for the effort:
  10 days (setup)
  PLUS 1 days per 20K LOC
  PLUS 0.5 days per case of item 1
  PLUS 1 day per case of item 2
  PLUS 1 day per executable built
  PLUS 20 days if item 3 applies

A rougher order of magnitude for the effort:
  10 days (setup)
  PLUS 1 day per 10K LOC
  PLUS 1 day per executable built
  PLUS 20 days if item 3 applies

Both estimates include time for "packaging"
and basic testing for proper operation.

For reference, we converted 1.5 Million LOC that
built over 100 executables from HP-UX to Solaris in
about 300 staff days.  A large part of the effort
was OS conversion issues, though we were also
converting from one Ada compiler to another,
which took about 40 days of the effort.

Reference manuals that can ease your job:
  DEC Tru64 OS Reference Manual
  HP-UX OS Reference Manual

I'm available for consulting on efforts such as this.  I've
converted a lot of code from HP-UX to Solaris, HP-UX to
DEC Tru-64, and DEC Tru-64 to Solaris.

Smooth Sailing LLC
"Then, after a second or so, nothing continued to happen."
Steven Deller
[log in to unmask]
410 757 6924