Re: writing to a floating point register ?

[Sven Luther <luther@dpt-info.u-strasbg.fr>]

On Wed, Feb 05, 2003 at 11:44:23AM +0100, Geert Uytterhoeven wrote:
> 
> Even if you could, it would work for 32-bit IEEE floating point format only.
> Is the hardware register format IEEE compatible.


Something like this :

unsigned long cfp32(unsigned long v, unsigned long d) {
        unsigned int x, vx, m, e;
        for (x=0, vx=v; vx>1; x++, vx>>=1);
        m = (x>22?v>>(x-22):v<<(22-x)) & 0x007fffff;
        e = ((x+127-d)<<23) & 0x7f800000;
        return (e | m);
}

Does the job. I don't really test for exponent overflow, but well,
anyone trying a video mode whose exponent is greater than 127 deserves
what gets.

Are there any other subtle things that may break with the above ?

Anyway thanks for your help.

Friendly,

Sven Luther


-------------------------------------------------------
This SF.NET email is sponsored by:
SourceForge Enterprise Edition + IBM + LinuxWorld = Something 2 See!
http://www.vasoftware.com