Convert the C Function Below to MIPS Assembly Language

Convert the C function below to MIPS assembly language. Make sure that your assembly language code could be called from a standard C program (that is to say, make sure you follow the MIPS calling conventions).
unsigned int sum(unsigned int n)
{
if (n == 0) return 0; else return n + sum(n-1);
}
This machine has no delay slots. The stack grows downward (toward lower memory addresses). The following registers are used in the calling convention: