... very good about backward compatibility within its primary productline, which began in 1978 with the 8086 CPU and now goes by the catchallterm ‘‘x86.’’ Within certain limitations, even programs ... arcane tricks are associated with increasing throughput, with names like prefetching, L1 and L2 cache, branchprediction, hyper-pipelining, macro-ops fusion, along with plenty of others.Some ... and have been extended to64 bits in width. The 64-bit versions of the registers are renamed beginning with an R: EAX becomes RAX, EBX becomes RBX, and so on. Over andabove the familiar general-purpose...