Sign Bit Extension

Sometimes you can get a value like this :

For example, something that is 12-bit in a 16-bit short int.

shortIntValue = 0b0000 1100 1110 1100

The latter 12 bits are the actual value. It is a negative value by the 12th bit being 1. And you really want :

0b1111 1100 1110 1100

You can do

shortIntValue <<= 4;

followed by

shortIntValue >>= 4;

Volia! Sign bit extension! This is useful for 2’s complement values which are put into a primitive integer size. (As above)


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Blog at

Up ↑

%d bloggers like this: