From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cagney <ac131313@cygnus.com>
To: Daniel Jacobowitz <dmj+@andrew.cmu.edu>
Cc: gdb-patches@sources.redhat.com
Subject: Re: [rfa] mips argument passing fixes for o32
Date: Thu, 12 Jul 2001 00:47:00 -0000
Message-id: <3B4D5552.4070403@cygnus.com>
References: <20010706112635.A5870@nevyn.them.org>
X-SW-Source: 2001-07/msg00284.html

> These are based on testsuite failures (call-*-st, if I remember correctly)
> and reading the argument passing code in GCC.  The struct alignment fix
> definitely agrees with the ABI, though it's not always clear on this point -
> it becomes necessary for us when the return value is a struct and thus there
> is a hidden pointer as the first argument.  The shift fix matches this
> comment in GCC and is not really specified by the ABI document:


I get the feeling that these two changes fix two separate bugs:

	o	botched struct parameter pass

	o	botched struct return

Looking at just the first one:

> +	  /* Structures should be aligned to eight bytes (even arg registers)
> +	     on MIPS_ABI_O32 if their first member has double precision. */
> +	  if (gdbarch_tdep (current_gdbarch)->mips_abi == MIPS_ABI_O32
> +	      && mips_type_needs_double_align (arg_type))
> +	    {
> +	      argreg += argreg & 1;
> +	    }

this is approved.  However could you please change the expression:


	argreg += argreg & 1;


to something like:


	if ((argreg & 1))
	  argreg++;

your original expression makes my head hurt :-)

	Andrew