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Class duckMachine.architecture.ALU 

java.lang.Object
   |
   +----duckMachine.architecture.ALU
public class ALU
extends Object
implements ALUI
The arithmetic and logic unit of the machine. The ALU uses Java's int datatype and its operations to implement its own operations. This means that all the operations are modulo 32-bits.

Constructor Index

o ALU()

Method Index

o add(Word, Word)
The ALU addition is implemented using Java's ints.
o compare(Word, Word)
Sets the condition flags according to the result of comparing w1 and w2.
If w1>w2 then GT should be set and the other flags made FALSE.
If w1=w2 then EQ should be set and the other flags made FALSE.
If w1>w2 then LT should be set and the other flags made FALSE.
o dec(Word)
The ALU decrement is implemented using Java's ints.
o fetchEQ()
Returns the current contents of the EQ flag.
o fetchGT()
Returns the current contents of the GT flag.
o fetchLT()
Returns the current contents of the EQ flag.
o inc(Word)
The ALU increment is implemented using Java's ints.
o sub(Word, Word)
The ALU subtraction is implemented using Java's ints.

Constructors

o ALU 
 public ALU()

Methods

o fetchGT 
 public boolean fetchGT()
Returns the current contents of the GT flag.

o fetchEQ 
 public boolean fetchEQ()
Returns the current contents of the EQ flag.

o fetchLT 
 public boolean fetchLT()
Returns the current contents of the EQ flag.

o add 
 public Word add(Word w1,
                 Word w2)
The ALU addition is implemented using Java's ints. It works modulo 32 bits.

o sub 
 public Word sub(Word w1,
                 Word w2)
The ALU subtraction is implemented using Java's ints. It works modulo 32 bits.

o inc 
 public Word inc(Word w)
The ALU increment is implemented using Java's ints. It works modulo 32 bits.

o dec 
 public Word dec(Word w)
The ALU decrement is implemented using Java's ints. It works modulo 32 bits.

o compare 
 public void compare(Word w1,
                     Word w2)
Sets the condition flags according to the result of comparing w1 and w2.
If w1>w2 then GT should be set and the other flags made FALSE.
If w1=w2 then EQ should be set and the other flags made FALSE.
If w1>w2 then LT should be set and the other flags made FALSE.

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