TAMS / Java / Hades / **applets** (print version): contents | previous | next#### Carry-lookahead adder sum block

**Description**

This is the 1-bit adder block used in the carry-lookahead adder.
It uses two XOR gates to calculate the *si* sum output bit
of the *ain*, *bin* and *cin* (carry in) input bits.

Obviously, this block generates a carry output signal when both the
ain and bin inputs are 1. Therefore, a simple AND gate is sufficient
to compute the generate-carry signal on the *gi* output.

Similarly, the OR gate computes the propagate carry signal on the
*pi* output.

Run the applet | Run the editor (via Webstart)

Impressum | 24.11.06

http://tams.informatik.uni-hamburg.de/applets/hades/webdemos/20-arithmetic/30-cla/sum_print.html