Help Needed for 16-bit ALU Design (MIPS)

[esmeco]

Homework Statement

Hello!


I need to implement a set greater than and a branch less or equal in my 16 bit ALU design(MIPS architecture),but I'm having many difficulties.

Homework Equations

The Attempt at a Solution

I know that in a set greater than a>b equals a-b>0 ,but I don't know how to work out from that and implement it in my design(which type of gates to use and that).
The same happens with branch less or equal.I already have a branch equal,but I don't know how to use it in order to get a ble.
Any help is really appreciated!

 

[esmeco]

These are,respectively the implementation of the sgt instruction and ble instruction:


http://img174.imageshack.us/img174/715/sgtop2.jpg


http://img405.imageshack.us/img405/6933/blegy6.jpg