Methods and apparatus are provided for accessing the proper memory in processors having program and data memories with different sizes. In some embodiments, a processor is optimized for data access and has registers that are the same size as the data memories. When a program is compiled, some implementations identify when a pointer variable points to a piece of data (data memory) or a function (program memory) and synthesize different sized operations accordingly. The proper mode and size are assigned for each pointer. Methods of the present invention do not require annotation of functions. Existing code does not need to be modified and there is no opportunity to introduce errors. The invention does not require extra program memory to be located at directly accessible locations to store stub code.