pg.1-3) The Alpha 21164 can issue four instructions in a single clock cycle. This combined with the low-latency and/or high-throughput features in the instruction issue unit and the on-chip components of the memory subsystem reduce the average cycles per instruction. All data manipulation is done between registers. The registers are 64 bits in length and all instructions are 32 bits in length. Memory operations are either load or store operations.Since many early computers had extremely limited memory and processing power, complex instruction sets were developed. Complex instruction computing or CISC processing is a CPU architecture in which a large number of instructions are hardcoded into the chip. Intel's Pentium processors still adhere to this philosophy.The Pentium processor was Intel's first CPU to employ superscalar architecture. With its 3.3 million transistors it is able to execute two instructions per clock cycle resulting in twice the integer performance relative of an Intel 486 CPU running at the same frequency. Pentium also employed on-chip dual-processing support as well as an onboard interrupt controller. Next came the Pentium Pro, which introduced dynamic execution technology that pre-dicts the program flow through multiple branches. Multiple branch prediction lets the CPU pre-fetch possible next instructions rather than waiting for the outcome. This technology can actually change the order of executed instructions based on analyzed data dependencies, which in turn provides optimum execution speed. However, the Pentium Pro was only available in speeds from 150MHz to 200MHz and has only 16KB of internal cache (half as much as the MMX).In 1997 Intel introduced the Pentium MMX processor. The MMX processor added1.2 million more transistors (4.5 million total) and also SIMD technology (Single Instruction, Multiple Data). SIMD technology included 57 new instructions, 4 new data types and eight 64-bit registers. As in the origi...
