This assignment builds on the previous assignment. A single bit, by itself, is not very useful. In order to represent values and addresses, we need multiple bits. For the machine that we are simulating, we will be using a 32-bit value for both addresses and values. A word is a collection of bits, originally the size that the machine “natively” works on. Along the history of computing, a word became 16 bits. A longword is a 32-bit collection of bits.
You must fully implement this interface (source file is provided). You must make a new class called “Longword” that does not inherit from anything. You must create a collection (array is best) of Bit (from assignment 1) and use that for storage. You may not use any other storage mechanism.
public interface ILongword {
bit getBit(int i); // Get bit i void setBit(int i, bit value); // set bit i's value longword and(longword other); // and two longwords, returning a third longword or(longword other); // or two longwords, returning a third longword xor(longword other);// xor two longwords, returning a third longword not(); // negate this longword, creating another longword rightShift(int amount); // rightshift this longword by amount bits, creating a new longword longword leftShift(int amount);// leftshift this longword by amount bits, creating a new longword @Override
String toString(); // returns a comma separated string of 0's and 1's: "0,0,0,0,0 (etcetera)" for example long getUnsigned(); // returns the value of this longword as a long int getSigned(); // returns the value of this longword as an int void copy(longword other); // copies the values of the bits from another longword into this one void set(int value); // set the value of the bits of this longword (used for tests)
}
Unlike what is actually done in hardware, you may use loops to implement the same operation done on each bit. You must use the operations from bit (and, or, not, xor, getBit, set) where appropriate. You must validate inputs where appropriate.
You must provide a test file (longword_test.java) that implements void runTests() and call it from your main, along with your bit_test.runTests(). As with the bit test, these tests must be independent of each other and there must be reasonable coverage. You can not reasonably test all 4 billion possible longwords, but you can test a few representative samples
