Re: [rfa] mips argument passing fixes for o32

Andrew Cagney
2001-07-12T00:47:00Z

> 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