Edit Step Mine's MP

ROL effectively multiplies the number of hours by 2, which is the same as minutes / 30. Replacing it with NOP just uses the number of hours, which is the same as minutes / 60. The shift instructions on the 65816 (LSR, ASL, ROR, ROL) are useful for multiplying and dividing by powers of 2. Multiplying and dividing by other numbers is not as simple. The SNES can also do hardware multiplication and division which is often faster than using the CPU, though there are some restrictions.

There are a few subroutines in the FF6 code that can do generic multiplication and division. For example, C1/18D9 and C2/4781 both do unsigned hardware multiplication.