Hi all, The Overlay mechanism implemented by Keil is ingenious. Moreover if we want add some functionnality in Eeprom without change ROM code is to my mind impossible because DATA GROUP area will be modified with new local variables used in our new functions in Eeprom. What do you think about this? Thanks a lot, Daniel
It would make sense to order the variables by occurence rather than some random? order. The variables are not ordered randomly. They are ordered according to their placement in the symbol table manager (in the compiler). It is the job of the symbol table manager to maintain symbols in a "database" that the compiler can search. Symbols must be maintained by name and by scope level and the strategy must be such that the compiler can locate a symbol very quickly (or else compiler speed suffers). If you were to take a look at different strategies for symbol table management algorithms you will find that this is a sufficiently complex thing to do and on the 8051 this is further complicated by the lack of stack frames. Jon
"If you were to take a look at different strategies for symbol table management algorithms ...." I am not concerned with that, that is a coding issue. Any algorithm can be used with assigning addresses in the sequence they exist in a module, rather than some other way. happy hollidays, Erik