On Thu, 05 Jun 2008 17:23:00 +0200 Stefan Reinauer <[EMAIL PROTECTED]> wrote:
> Jan Kleinsorge wrote: > > Pavel Roskin wrote: > > > >> Hello! > >> > >> I tried to compile the current grub on Fedora 9 for PowerPC, but it > >> failed due to floating point usage in ls. Sorry, I don't have the > >> exact message handy. > >> > >> Anyway, there are several references to "float" and "double" in the > >> code, and I think it's wrong. GRUB should be able to work on > >> systems with no floating point support and on systems where the > >> floating point device needs to be activated. Even Linux kernel > >> avoids using floating point. > >> > >> If everyone is fine, I'll try to remove all floating point stuff > >> from the code. > >> > >> > > Hi Pavel, > > > > there is no need for hard-float support on the target machine. The > > libgcc provides all the software-emulation routines. Given that > > GRUB is linked against it. Which is likely as it is a necessity > > when compiling with gcc. Maybe your compilation is simply broken > > because of that one missing. Could you please post the error > > message? > Nonetheless, using Floating Point operations in bootloaders and > firmware is highly discouraged. If Floating Point is required for a > bootloader (except, maybe, possibly, at all, for encryption) the > bootloader is definitely broken, either in implementation or in > design. > > Also keep in mind, most operating systems expect the FPU to be in > power on state. > > Stefan The bootloader is "broken" if it uses floating point arithmetic? I think that while GRUB should not REQUIRE an FPU, it could use software floating point if there was a good reason to do so (and it would not be broken as long is it was done portably). Though I only have minimal knowledge of encryption algorithms, I don't think that floating point math is often used. I think that avoiding floating point math as Pavel Roskin suggested is good, though I don't agree that Stefan's assertion that any use of floating point math is necessarily "broken" -- it might be better to say that we'd prefer not to pull in softfloat libraries (necessary since many targets have no FPU); therefore it is desirable to avoid floating point math. Colin _______________________________________________ Grub-devel mailing list Grub-devel@gnu.org http://lists.gnu.org/mailman/listinfo/grub-devel