It's in Lib/Rabbit4000/BIOSLIB/CPUPARAM.LIB https://github.com/digidotcom/DCRabbit_10/blob/master/Lib/Rabbit4000/BIOSLIB/CPUPARAM.LIB#L12 https://github.com/digidotcom/DCRabbit_10/blob/master/Lib/Rabbit4000/BIOSLIB/CPUPARAM.LIB#L12

// Revision of Dynamic C library files, independent of compiler version.
// Included here (CPUPARAM.LIB) as a library used by BIOS and user programs.
// First appeared in 10.72C release. Will be ' ' (space) for first release of
// a new compiler version (see CC_VER) or 'A' to 'Z' when libraries revised.
#define CC_REV 'D' Start a New Thread

For DC v10.72, how is macro CC_REV defined?  Is the value going to be 1072D, _1072_D_, etc. I need to know what to test for.
Steve Start a New Thread