ACA Unit 8 Hardware and Software for VLIW and EPIC Notes — Unit 8 – Download as PDF File .pdf), Text File .txt) or read online. G-2 Appendix G Hardware and Software for VLIW and EPIC. In this chapter we discuss compiler technology for increasing the amount of par- allelism that we. View Notes – from ENG at BGS Institute of Technology. | Website for.

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The Trace Family of computers was available in three sizes where each size replicated a cluster. The total schedule length TL is the number of cycles to complete one hardwrae iteration. Tomasulo algorithm Reservation station Re-order buffer Register renaming. This improves power efficiency by eliminating the fetch, decode, and execution of unused speculated instructions.

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Since the earliest days of computer architecture, [1] some CPUs have added several arithmetic logic units ALUs to run in parallel. Since determining the order of execution of operations including viw operations can execute simultaneously is handled by the compiler, the processor does not need the scheduling hardware that the three methods described above require.

Patent 6,, September The shortest path through the code now computes only one full iteration of the loop. Typical bit instruction encoding format.

These data show that 8. Within each of the multiple-opcode instructions, a bit field is allocated to denote dependency on the prior VLIW instruction within the program instruction stream. If the CPU guesses wrong, all of these instructions and their context need to be flushed and the correct ones loaded, which takes time. He realized that to get good performance and target a wide-issue machine, it would be necessary to find parallelism beyond that generally within a basic block. This has led to increasingly complex instruction-dispatch logic that attempts to guess correctlyand the simplicity of the original reduced instruction set computing RISC designs has been eroded.

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Because ILP must be explicitly expressed in the program code, VLIW compiler optimizations often replicate instructions, increasing code size. This eliminates the NOP that often occurs after a load instruction in control-oriented code.

Multiple Issue Processors: Superscalar and VLIW

We presented the code-size reduction and performance impact of using these techniques to compile a set of 84 benchmarks. Because it has less ILP and is characterized by short test-and-branch sequences, pipeline NOPs occur more often in control-oriented code.

Fetch packets are aligned on bit 8-word boundaries. The compiler provides options to select the processor generation and to disable optimization passes that target specific processor features. These three methods all raise hardware complexity. It consists of stages of II cycles each. The pipelined version of the loop, with the fully collapsed epilog, is now safe for all trip counts greater than zero.

Therefore, if the compiler did not have any information about the trip counter, it would have been worth collapsing the last epilog stage to eliminate the need for compensation code. Each instruction on the C6X-1 processors is bit.


Co-design of Compiler and Hardware Techniques to Reduce Program Code Size on a VLIW Processor

The compiler can, in many cases, exploit ILP better than hardware, and the saved silicon space can be used to reduce cost, fkr power, or add more functional units 1. Code-size reduction and performance improvement on DSP and multimedia application benchmarks. In contrast, one VLIW instruction encodes multiple operations, at least one operation for each execution unit of a device.

It has 32 static general-purpose registers, partitioned into two register files. The instruction schedule for a software-pipelined loop has three components: Very long instruction word computing Digital signal processing Instruction processing Instruction set architectures Parallel computing.

Due to the design requirements of a high performance VLIW processor, bit instructions must be kept on a bit boundary.

The Cydra 5 computer developed at Cydrome Inc. Bits are p-bits for bit instructions. Load instructions have four delay slots, multiplies have one delay slot, and branches have five delay slots.

There is a distinct difference in the results between control- and loop-oriented benchmarks. The goal is to minimize the degradation as much as possible.