Re: Calling conventions (particularly 32-bit ARM)

MitchAlsup1 <mitchalsup@aol.com> wrote:

On Thu, 16 Jan 2025 3:02:44 +0000, Waldek Hebisch wrote:
 

MitchAlsup1 <mitchalsup@aol.com> wrote:

>

>

Pass by COMMON block was even faster.

>
I do not think so.  I LAPACK-like cases there are array arguments.
Normal calling convention needs to store and later read parameters
and pass addresses.  COMMON would force copying of entire arrays,
much less efficienct than handling parameters.

 
      SUBROUTINE FOO
      COMMON /ALPHA/ i,j,k,a[100],b[100],c[100,100]
 
See no arguments, passed directly by common-block, no copying of
data, no dope vectors needed.

No copy only if there is single set of arguments.  If there are
different arguments, then one needs to pass them, that is copy
them.

--
                              Waldek Hebisch