What does y -= m < 3 mean?

Question

While looking through some example C code, I came across this:

y -= m < 3;

What does this do? It it some kind of condensed for loop or som

Answer 1

< has a higher priority to the sign of equal = so m<3 returns 1 if m is less than 3, and else is 0

then y = y - 1 or y = y - 0