To find the original price \( p \) of the shirt, we can set up the equation based on the information given:
The shirt now costs $7.98, which is half of its original price. Therefore, we can express this relationship as:
\[ \frac{p}{2} = 7.98 \]
To solve for \( p \), we can multiply both sides of the equation by 2:
\[ p = 7.98 \times 2 \]
Now, calculate the right side:
\[ p = 15.96 \]
Thus, the original price \( p \) of the shirt is:
\[ \boxed{15.96} \text{ dollars} \]