Re: i370 port

["Paul Edwards" <mutazilah@gmail.com>]

Hi Ulrich.

I'm getting back to this after a long hiatus.

I have reviewed the 'W' code in PRINT_OPERAND:

else if (CODE == 'W')
  {
    /* hand-built sign-extension of signed 32-bit to 64-bit */
    mvs_page_lit += 8;
    if (0 <=  INTVAL (XV)) {
       fprintf (FILE, "=XL8'00000000");
    } else {
       fprintf (FILE, "=XL8'FFFFFFFF");
    }
    fprintf (FILE, "%08X'", INTVAL (XV));
  }

and it looks to me like it is already correct. If movdi is given a
const_int as a parameter, then sign-extending to 64-bit is
exactly what needs to happen, isn't it?

I'm only expecting to compile programs as 32-bit, so I'm not
expecting more than 32-bit integers. The IFOX assembler
won't do more than that. In case that's the issue.

But regardless I don't know how to make this code:

mvs_check_page (0, 6, 8);
return \"MVC^I%O0(8,%R0),%1\";

make use of that 'W' operand.

Do I change that %1 to %W1 perhaps?

I'll give that a try tomorrow.

Thanks.  Paul.





-----Original Message----- 
From: Ulrich Weigand 
Sent: Monday, August 22, 2011 10:22 PM 
To: Paul Edwards 
Cc: gcc@gcc.gnu.org 
Subject: Re: i370 port 

Paul Edwards wrote:

>   if (operands[1] == const0_rtx)
>   {
>     CC_STATUS_INIT;
>     mvs_check_page (0, 6, 8);
>     return \"MVC    %O0(8,%R0),=XL8'00'\";
>   }
>   mvs_check_page (0, 6, 8);
>   return \"MVC    %O0(8,%R0),%1\";
> }"
>    [(set_attr "length" "8")]
> )
> 
> forces it to use XL8'00' instead of the default F'0' and that
> seems to work.  Does that seem like a proper solution to
> you?

Well, there isn't really anything special about const0_rtx.
*Any* CONST_INT that shows up as second operand to the movdi
pattern must be emitted into an 8 byte literal at this point.

You can do that inline; but the more usual way would be to
define an operand print format that encodes the fact that
a 64-bit operand is requested.

In fact, looking at the i370.h PRINT_OPERAND, there already
seems to be such a format: 'W'.  (Maybe not quite; since 'W'
sign-extends a 32-bit operand to 64-bit.  But since 'W'
doesn't seem to be used anyway, maybe this can be changed.)

Bye,
Ulrich

-- 
  Dr. Ulrich Weigand
  GNU Toolchain for Linux on System z and Cell BE
  Ulrich.Weigand@de.ibm.com