Re: [PATCH] - Use of powerpc 64bit instructions in 32bit ABI

[Fariborz Jahanian <fjahanian at apple dot com>]

On Tuesday, October 14, 2003, at 04:13 PM, Richard Henderson wrote:

> On Tue, Oct 14, 2003 at 03:50:12PM -0700, Fariborz Jahanian wrote:
> > However, when it comes to the abi-specific areas such as, passing
> > arguments, returning function values, etc. Only 32bit half of the
> > register is used.
>
> Sure.  Can you explain why just having the target-specific parts
> return SImode for various values is insufficient?
>
>
>
> r~

Best to quote from the patch:

load_register_parameters needs to count number of  registers  used to 
pass a structure by value.
This is computed by  (size + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD 
which has the assumption that
size of register in use is same as natural word size. In the mixed mode 
this does not hold. Is there a better way
to do this computation?

*************** load_register_parameters (struct arg_dat
*** 1602,1608 ****
          else if (TYPE_MODE (TREE_TYPE (args[i].tree_value)) == 
BLKmode)
            {
              size = int_size_in_bytes (TREE_TYPE (args[i].tree_value));
!             nregs = (size + (UNITS_PER_WORD - 1)) / UNITS_PER_WORD;
            }
          else
            size = GET_MODE_SIZE (args[i].mode);
--- 1606,1612 ----
          else if (TYPE_MODE (TREE_TYPE (args[i].tree_value)) == 
BLKmode)
            {
              size = int_size_in_bytes (TREE_TYPE (args[i].tree_value));
!             nregs = (size + (UNITS_PER_REGISTER_ARGUMENT - 1)) / 
UNITS_PER_REGISTER_ARGUMENT;
            }
          else
            size = GET_MODE_SIZE (args[i].mode);