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[Fwd: FLOAT INFO QUESTION]


 



Can you please forward this to the gdb list ?
It keeps sending it back. XFREE86 is a junk mail
server? 

Thanks very much,
Takis
PS: Remove the above comment ...

---------- Forwarded message ----------
Date: Thu, 22 Jun 2000 06:47:32 -0700 (PDT)
From: takis@xfree86.org
To: gdb@sourceware.cygnus.com
Subject: FLOAT INFO QUESTION


Hello,
I had a look in the new float info routines
of gdb 5.0 and I am a little confused. If you look
in <linux/processor.h> you will find that the 387 
structure is like 
        cwd (fctrl)
        swd (fstat)
        twd (ftag)
        fip
        fcs
        foo
        80 bytes = 8*10  
        status

Now in the operating system that I run (aka DG/UX unix)
and want to do a port of 5.0, I find the structure:

struct fpregset {
           
             union{

                    struct fpchip_state fpchip_state;
                    emulation struct
                    int f_fpreg[62];
                  }

                  long f_wregs[33]; /* weitek */
                 }

Where: struct fpchip_state {
                  int state[27];
                  int status;
                 }

So the first member reserves 108 bytes = 7 4 bytes fpregs + 8 *10.
Tah agrees with the linux idea.

Now in GDB-5.0 we find in tm-i386.h a new layout as

   fctrl, fstat, ftag, fiseg, fioff, foseg, fooff, fop

Which is clearly different from the struct of linux. Basically          
if I want to unpack fpchip_state above to floating regs I dont know
if the order is fctrl, fstat, ftag , fiseg(=fcs), fioff(=?) , ????
or (what I always thought is)

  fctrl,fstat,ftag,fip,fcs,fopoff,fopsel,status

And in this new layout in tm-i386.h which one is the status? I
clearly have 108 bytes so how I would obtain the fop 
mentioned in tm-i386.h?

Regards, 
T.






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