If data is present in upper level it is a hit, if not, it is a miss. Data is only copied between adjacent levels, cannot skip levels. ![]() Memory Review Memory Hierarchy Definition A block is the unit size that is copied, may be a word or multiple words. ![]() ![]() This avoids the need for compiler scheduling but it still may help. The CPU will ensure that the code semantics are followed. instructions each cycle to avoid hazards. CPU looks at the instruction stream and chooses instructions. The compiler may have to pad some spots with NOP MIPS Static Duel Issue Each packet has two instructions: one ALU/branch and one load/store Dynamic Multiple Issue (superscalar) processors (at run time). The instructions are grouped to avoid hazards as much as possible between packets and there can be no dependencies within the packet. Sometimes this is called a VLIW-very long instruction word, it specifies concurrent operations. The compiler groups instructions into issue packets that will be issued together in a clock cycle. both of these can be done at compile time or execution time. decide which instructions to issue in a clock cycle (packaging), deal with data and control hazards. Compiler groups instructions to be issued together.
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