To find the original price \( p \) of the shirt, we are given that the sale price of $7.98 is half of its original price. We can express this relationship with the following equation:
\[ \frac{p}{2} = 7.98 \]
To solve for \( p \), we can multiply both sides of the equation by 2:
\[ p = 2 \times 7.98 \]
Now, let's calculate that:
\[ p = 15.96 \]
Thus, the original price \( p \) of the shirt is:
\[ p = 15.96 \text{ dollars} \]