Understanding Binary and Decimal in Verilog

When working with binary integers in Verilog, each bit represents a power of two, with the least significant bit being 1. For instance, decimal 13 can be represented as 1101 in binary: 8 + 4 + 1 = 13.

Verilog is known for its simplicity and flexibility when it comes to working with numbers. In fact, most FPGAs have dedicated DSP blocks that enable fast multiplication and addition of integers. This makes it possible to take advantage of a fixed-point approach, which can often be implemented with little effort using simple fixed-point math.

In Verilog, unsigned values are treated as having zero extension, meaning that any leading zeros in the binary representation are ignored. On the other hand, signed values are treated as having sign extension, where the most significant bit (MSB) is used to determine the sign of the number.

The Verilog standard specifies that only the expression determines whether a number is signed or unsigned. This means that you do not need to explicitly define the MSB of a signed value; instead, you can use the $signed system function or define signed wires and registers.

When working with signed and unsigned values in Verilog, it's essential to keep in mind the following rules:

* Any operation on two operands, unless both operands are signed, yields an unsigned value.

* Any operation that involves a signed operand will produce a signed result.

* The $signed system function can be used to convert an unsigned value to a signed value.

For example, to multiply a signed register with an unsigned register and treat the result as a signed value, you would need to use the following code:

```verilog

reg a; // Unsigned reg

wire signed b;

assign signed_a = $signed(a); // Convert to signed

assign a_mult_b = signed_a * b;

```

In conclusion, understanding binary and decimal representations in Verilog is crucial for efficient and effective programming. By following the guidelines outlined above and using fixed-point math and DSP blocks where possible, you can simplify your code and achieve better performance.

Binary decimal verilog