Comment author: administrator

Floats don't work with bytecode (ocamlrun) on the iPAQ.
You get strange results but on the native (ocamlopt) version
it works though. First I got this using a cross-compiled ocamlc
but later I compiled ocamlc natively and I get exactly the
same behaviour.
I don't know what's going on but if I can help tell me.
You can do tests natively by using the skiffcluster from Compaq CRL
see the following URL :
http://www.handhelds.org/projects/skiffcluster.html

The iPAQ has Linux 2.4.16/glibc 2.2.4 with Ocaml 3.04

let main () =
let x = 5.2 in
let y = 6.3 in
let z = x +. y in
print_float x;
print_string " + ";
print_float y;
print_string "=";
print_float z;
print_string "\n";;

main();;

I tested the program above on skiffcluster5 using OCaml 3.04 and it
worked fine in bytecode. (I compiled OCaml on that machine a couple
of weeks ago and did not have the fortitude to recompile it again, so
something might have changed in their C compiler since then.)

AFAIK, floats are software emulated on the Strong Arm, either by the C
library or the kernel, and I have long suspected that the emulation
has a few quirks -- one of my test cases (an FFT implementation)
never produced the right results when compiled with ocamlopt, although
the bytecode version was OK. Still, the bytecode interpreter is a C
program like any other, so it is surprising that it would run into
floating-point problems that other C programs would not run into.

Best regards,

• Xavier Leroy

Comment author: administrator

Could not reproduce