4.3 consider the following instruction mix: 24% 28% 25% 10% 11% 2% 4.3.1 [5] < §4.4> what fraction of all instructions use data memory? 4.3.2 [5] < §4.4> what fraction of all instructions use instruction memory? 4.3.3 [5] < §4.4> what fraction of all instructions use the sign extend? 4.3.4 [5] < §4.4> what is the sign extend doing during cycles in which its output is not needed?