Re: How parameters are passed.

Even more efficient is to simply load the parameter value to a register and have the called function use the value, in the register, as is.  The backend (not the compilers per se) will, for some parameter types, do this form of optimization under the covers.

Bruce
Bruce Vining Services
507-206-4178

--- On Thu, 1/29/09, Adam Glauser <adamglauser@xxxxxxxxx> wrote:

From: Adam Glauser <adamglauser@xxxxxxxxx>
Subject: Re: How parameters are passed.
To: rpg400-l@xxxxxxxxxxxx
Date: Thursday, January 29, 2009, 8:45 AM

Alan Campin wrote:

Obviously it is a lot more efficient to push the integer on the stack
(4 bytes) instead of creating a work variable, copy the value to it,
get a pointer and push pointer onto the stack (16 bytes) and then
throw away when done.

IIRC, Barbara has stated in the past that work variables may be reused
for different operations in certain circumstances. So, FWIW, the
compiler may not always need to allocate memory in the case you describe.