Generating Music Tones, How to handle when tones overlap? (16bit samples) If i add the two tones then the result if two peaks are added together will be greater then the the sample max (2^15).

For the life of me I couldn't think of the right words to google. Think i have google block.
If you can't tolerate any distortion, then divide by 2 the amplitude of the signals you want to mix.

Please check this question