Spec: https://cs61c.org/sp22/projects/proj2/
TODO: describe what you did Bug fixed log:
- callers can assume that the callee will not modify saved registers
- Save all the a registers before make a function call
- You cannot assume t registers are not modified between function calls
- s0 is modified? typo in prologue
- m1 stands for mum of clms
- using ebreak to circumscribe the scope
- learn to read ** char: *(a0+4) -> lw a1, 4(a0)