Amdahl's Law - performance improvement to be gained from using some faster mode of execution is limited by the fraction of the time the faster mode is used. Add operation - 3 operands with destination first.
Arithmetic operations use registers for operands.
Registers - 32 registers each 32 bits wide. Simplicity favors regularity. Number of registers influences the design. Smaller is faster. Homework assignment lecture 6 - MIPS instructions Primary memory is bigger and slower than registers.