Re: Floating point usage

[Stefan Reinauer]

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


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