I am working on a project where we are just about to merge the firmware for our product with the firmware from another product so we can add that product as a "feature" of ours. I'm concerned that the combined stack needs of our code plus theirs will well exceed what we have available in our current configuration.

We're using an 8051 derivative from Philips (SAA56xx) which has 256 bytes "internal" RAM and 2K "xdata" RAM. We are also using an older version of the IAR Embedded Workbench tools.

Can anyone tell me how to maximize the available stack space? I've seen the "stack expansion (-u)" compiler option and a reference to an Xstack in the IAR help, but I'm not sure how to use these.