# DMux8Way Chip

### DMux8Way (8-way Demultiplexor) Chip

An 8-way Demultiplexor chip outputs the given input to certain output pin, which is specified by selector bit.

{% hint style="info" %}
Width of selector bit = (log 8) to the base 2 = 3
{% endhint %}

```nand2tetris-hdl
Chip name: DMux8Way
Inputs: in, sel[3]
Outputs: a, b, c, d, e, f, g, h
Function: If sel=000 then {a=in, b=c=d=e=f=g=h=0}
                else if sel=001 then {b=in, a=c=d=e=f=g=h=0}
                else if sel=010 ...
                ...
                else if sel=111 then {h=in, a=b=c=d=e=f=g=0}.
```

![Abstraction of 8-way Demultiplexor Chip - Representation](https://www.electronicshub.org/wp-content/uploads/2015/07/1-to-8-Demux.jpg)

### Implementation of DMux8Way Chip in HDL

The function in the above abstraction can help in the implementation of DMux8Way Chip.

{% hint style="info" %}
You can use the DMux4Way Chip that you've built earlier.
{% endhint %}

```nand2tetris-hdl
CHIP DMux8Way {
    IN in, sel[3];
    OUT a, b, c, d, e, f, g, h;

    PARTS:
    DMux(in=in, sel=sel[2], a=abcd, b=efgh);
    DMux4Way(in=abcd, sel=sel[0..1], a=a, b=b, c=c, d=d);
    DMux4Way(in=efgh, sel=sel[0..1], a=e, b=f, c=g, d=h);
}
```

### Implementation of DMux8Way Chip in Java™

*Similar to the Implementation in HDL*

```java
package CombChips;

class DMux8Way_Gate extends DMux4Way_Gate {
    
    protected static int[] DMux8Way(int in, int sel) {
        int[] arr_sel = new int[3];

        int[] subarr_sel = new int[2];
        System.arraycopy(arr_sel, 1, subarr_sel, 0, subarr_sel.length);

        int[] temp = DMux(in, arr_sel[0]);
        int[] temp1 = DMux4Way(temp[0], subarr_sel);
        int[] temp2 = DMux4Way(temp[1], subarr_sel);

        int[] out = new int[4];
        System.arraycopy(temp1, 0, out, 0, temp1.length);
        System.arraycopy(temp2, 0, out, temp1.length, temp2.length);

        return out;
    }
}
```


---

# Agent Instructions: Querying This Documentation

If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter:

```
GET https://gittest2121.gitbook.io/nand2tetris/combinational-chips/dmux8way-chip.md?ask=<question>
```

The question should be specific, self-contained, and written in natural language.
The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.