Re: fx_offset Population

[Tracy Kuhrt <Tracy dot Kuhrt at microchip dot com>]

Ian,

Great!  Thanks for helping me figure this one out.  Agree that it is better to fix
the root problem than just the symptom.

Tracy


Ian Lance Taylor wrote:

> Tracy Kuhrt <Tracy.Kuhrt@microchip.com> writes:
>
> > The new target that I am porting is using a COFF format.  I am trying to
> > place the addend value in the 16-bits that I have for this operand.  Where
> > the problem comes in is after fixup_segment calls the md_apply_fix3 function
> > (which divides this addend by 2) it then checks to see that the value it will
> > be writing is able to fit into 2 bytes.  2147450880 (0x7FFF8000) does not fit
> > and I get the error "Value of 2147450880 too large for field of 2 bytes at
> > 0".  But a -32768 should fit in 2 bytes.
> >
> > Does this mean that anywhere that my md_apply_fix3 function uses the
> > fx_offset field in a calculation it must first convert it back to a signed
> > value?
>
> Yes, md_apply_fix3 must apply any relocation changes using the correct
> type of arithmetic.  In this case, it presumably must use signed
> division.
>
> Always making fx_offset signed is no more correct than always making
> it unsigned.  Either way, md_apply_fix3 is responsible for doing the
> right thing.
>
> Ian