Re: Calling conventions (particularly 32-bit ARM)

On Wed, 15 Jan 2025 3:31:47 +0000, John Levine wrote:

According to MitchAlsup1 <mitchalsup@aol.com>:

I would think that for Fortran (==everything passed by reference)
memory would beat registers most of the time.

>
Pass by COMMON block was even faster.

>
Sometimes.  On machines that don't have direct addressing, such as
S/360,
the code needs to load a pointer to the data either way so it's a wash.
>
Even when you do have direct addressing, if code is compiled to be
position indepedent, the common block wouldn't be in the same module
as the code that references it so it still needs to load a pointer
from the GOT or whatever its equivalent is.

Pass by COMMON block allows one to pass hundreds of data values in a
single call.
You are treating the common block as if it had but one data container.