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In computer architecture, a trace cache or execution trace cache is a specialized instruction cache which stores the dynamic stream of instructions known as trace. It helps in increasing the instruction fetch bandwidth and decreasing power consumption (in the case of Intel Pentium 4 ) by storing traces of instructions that have already been ...
SSE2 extends MMX instructions to operate on XMM registers. Therefore, it is possible to convert all existing MMX code to an SSE2 equivalent. Since an SSE2 register is twice as long as an MMX register, loop counters and memory access may need to be changed to accommodate this.
Below is the full 8086/8088 instruction set of Intel (81 instructions total). [2] These instructions are also available in 32-bit mode, in which they operate on 32-bit registers (eax, ebx, etc.) and values instead of their 16-bit (ax, bx, etc.) counterparts.
(Such Cache to Cache transfers can reduce the read miss latency if the latency to bring the block from the main memory is more than from Cache to Cache transfers, which is generally the case in bus based systems.) Snooping Operation: In a snooping system, all caches on a bus monitor all the transactions on that bus. Every cache has a copy of ...
Both provide cache-control instructions intended to minimize cache pollution when working on streams of data. They also exhibit important differences. Unlike SSE2, VMX/AltiVec supports a special RGB "pixel" data type, but it does not operate on 64-bit double-precision floats, and there is no way to move data directly between scalar and vector ...
Other than code-restructuring mentioned above, the solution to cache pollution is ensure that only high-reuse data are stored in cache. This can be achieved by using special cache control instructions, operating system support or hardware support. Examples of specialized hardware instructions include "lvxl" provided by PowerPC AltiVec.
Cache prefetching can be accomplished either by hardware or by software. [3]Hardware based prefetching is typically accomplished by having a dedicated hardware mechanism in the processor that watches the stream of instructions or data being requested by the executing program, recognizes the next few elements that the program might need based on this stream and prefetches into the processor's ...
Multiple virtual cores can push threadlets into the reorder buffer of a single physical core, which can split partial instructions and data from multiple threadlets through the execution ports at the same time. Each virtual core keeps track of the position of the relative output.