Search results
Results From The WOW.Com Content Network
An instruction set architecture (ISA) is an abstract model of a computer, also referred to as computer architecture.A realization of an ISA is called an implementation.An ISA permits multiple implementations that may vary in performance, physical size, and monetary cost (among other things); because the ISA serves as the interface between software and hardware.
The first was the CISC (Complex Instruction Set Computer), which had many different instructions. In the 1970s, however, places like IBM did research and found that many instructions in the set could be eliminated. The result was the RISC (Reduced Instruction Set Computer), an architecture that uses a smaller set of instructions.
The key difference between SIMT and SIMD lanes is that each of the SIMT cores may have a completely different Stack Pointer (and thus perform computations on completely different data sets), whereas SIMD lanes are simply part of an ALU that knows nothing about memory per se.
The first documented computer architecture was in the correspondence between Charles Babbage and Ada Lovelace, describing the analytical engine.While building the computer Z1 in 1936, Konrad Zuse described in two patent applications for his future projects that machine instructions could be stored in the same storage used for data, i.e., the stored-program concept.
Out-of-order execution, branch prediction, Harvard architecture: AMD K8: 2003 64-bit, integrated memory controller, 16 byte instruction prefetching AMD K10: 2007 Superscalar, out-of-order execution, 32-way set associative L3 victim cache, 32-byte instruction prefetching: ARM7TDMI (-S) 2001 3 ARM7EJ-S: 2001 5 ARM810 5
The critical difference is that in a custom logic design, changes to the individual steps require the hardware to be redesigned. Using microcode, all that changes is the code stored in the memory containing the microcode.
The instruction set architecture of a CPU will almost always define a set of registers which are used to stage data between memory and the functional units on the chip. The register file is part of the architecture and visible to the programmer, as opposed to the concept of transparent caches .
An analogy is the difference between scalar and vector arithmetic. A superscalar processor is a mixture of the two. A superscalar processor is a mixture of the two. Each instruction processes one data item, but there are multiple execution units within each CPU thus multiple instructions can be processing separate data items concurrently.