It's getting kind of quiet here so I'll throw one out... It appears to me that one could run both reentrancy models (small using IDATA and large using XDATA) simultaneously. To what benefit I'm not sure but it'd be one way to get recursion/reentrancy support without forcing all functions into the large model. I could imagine your small fast oft called leaf functions get compiled as non-reentrant small (if not really reentrant), your reentrant functions shared by ISR's and background tasks in the reentrant small model, and your big fat worker tasks in the reentrant large model. What say you? - Mark