computer organization and design notes(1)

design principle:

1 Simplicity favors regularity 

   Hardware for a variable of number of operands is more complicated than hardware for a fixed number.

2 Smaller is faster

   So MIPS architecture just have 32 registers. A very large number of registers may increase the clock cycle time.

3 Make the common case fast

   MIPS has immediate instructions because constant operands occur frequently, and by including constants inside arithmetic instructions, they are much faster than if constants were loaded from memory.

4 Good design demands good compromises

   The compromise chosen by the MIPS designers is to keep all instructions the same length, thereby requiring different kinds of instruction formats for different kinds of instructions, such as the R-format for register and the I-format for immediate and
data transfer instructions.