Re: [RFA] sh-tdep.c: Fix little endian problem with doubles

[Elena Zannoni <ezannoni at redhat dot com>]

Corinna Vinschen writes:
 > On Mon, Oct 13, 2003 at 10:18:46AM -0400, Elena Zannoni wrote:
 > > Corinna Vinschen writes:
 > >  > Erm... sorry, I don't quite understand.  An `else if' in conjuction
 > >  > with what `if'?  Actually, the double case is handled normally in
 > >  > BE mode, it's only slightly different in LE mode in that the registers
 > >  > are swapped.  The above code just makes the swap so I really don't see
 > >  > what the problem is.
 > > 

Corinna, whatever. I'll clean it up myself. I am tired of arguing. Please
check it in.

elena


 > > I mean: the function is structured so that there is pretty much a
 > > clause for each possible type. Just add another one. I don't care if
 > > there is a bit of code duplication. Something like that, or similar.
 > > 
 > > 	  else if (TYPE_CODE (type) == TYPE_CODE_FLT
 > > 		   && flt_argreg <= FLOAT_ARGLAST_REGNUM
 > > 		   && TYPE_LENGTH(type) == reg_size)
 > > 		   { do old stuff}
 > > 
 > > 	  else if (TYPE_CODE (type) == TYPE_CODE_FLT
 > > 		   &&  TYPE_LENGTH(type) == 2 * reg_size
 > > 		   && flt_argreg <= FLOAT_ARGLAST_REGNUM)
 > > 		   {
 > >                      if (TARGET_BYTE_ORDER == BFD_ENDIAN_LITTLE)
 > > 		     {do something}
 > >                      else
 > >                      {do something else}
 > >                    }
 > > 
 > >           else if (blah)
 > 
 > Hmm, but you see that this messes up the code more than it cleans it up,
 > don't you?  The reg_size variable depends already on the decision, that
 > we know if the argument goes in a general or a floating point register.
 > So the outer if/else if's do have to be kept as they are, to be able to
 > evaluate the register size correctly, and only then the code can react
 > on the information that it's a regsize or 2*regsize argument.  Except we
 > drop the reg_size variable again, since we know that registers are always
 > 4 byte anyway.
 > 
 > > Actually, the test that (flt_argreg <= FLOAT_ARGLAST_REGNUM) may not
 > > be sufficient anymore, because you are going to be using 2 registers,
 > > and you could end up beyond FLOAT_ARGLAST_REGNUM. Or is it fine to
 > > have the argument using the last float register, and the stack? Hmm,
 > 
 > No.  See the code right before the loop.
 > 
 > > is sh_next_flt_argreg taking care that doesn't happen? Seems so.
 > 
 > Yes.  Consider that doubles are always passed in even register pairs.
 > 
 > Corinna
 > 
 > -- 
 > Corinna Vinschen
 > Cygwin Developer
 > Red Hat, Inc.