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.

Author: Gardakora Yozshushura
Country: Ethiopia
Language: English (Spanish)
Genre: Art
Published (Last): 1 November 2013
Pages: 307
PDF File Size: 14.45 Mb
ePub File Size: 2.94 Mb
ISBN: 856-9-51078-932-8
Downloads: 48319
Price: Free* [*Free Regsitration Required]
Uploader: Melmaran

Notes for Advanced Computer Architecture – ACA by Tarini Mishra

These three methods all raise hardware complexity. As the instructions in the loop body are fetched and executed, they are stored in the loop buffer along with their insertion order. Retrieved from ” https: It has 32 static general-purpose registers, partitioned into two register files.

In the VLIW mode, the processor always fetched two instructions and assumed that one was an integer instruction and the other floating-point. By necessity, the bit instructions have reduced functionality.

Figure 4 is a generalization of the C6X bit three operand instruction encoding format. Instructions are fetched eight at a time from program memory in bundles called fetch packets. The loop body is demarcated by special instructions. There is a distinct difference in the results between control- and loop-oriented benchmarks.

The compressor has the responsibility for packing instructions into fetch packets. Code-size reduction and performance improvement on DSP and multimedia application benchmarks.

There is no harm in executing this instruction an extra time. Prologs frequently cannot be completely collapsed and often require a predicate register per collapsed stage.

Notes for Advanced Computer Architecture – ACA by Tarini Mishra

The Cydra 5 computer developed at Cydrome Inc. This design is intended to allow higher performance without the qnd inherent in some other designs.


However, EPIC architecture is sometimes distinguished from a pure VLIW architecture, since EPIC advocates full instruction predication, rotating register files, and a very long instruction word that can encode non-parallel instruction groups. Minimizing physical memory requirements reduces total system cost and improves performance and power efficiency. Contemporary VLIWs usually have four to eight main execution units.

Load instructions have four delay slots, multiplies have one delay slot, and branches have five delay slots. Please help improve this article by adding citations to reliable sources. For a bit instruction, the corresponding two p-bits in the header are not used set to 0. It then selects the overlay that packs the most instructions in the new fetch packet. Bits are p-bits for bit instructions. The compiler implements instruction tailoring via the following techniques: Multiflow was too early to catch the following wave, when chip architectures began to allow multiple-issue CPUs.

Very long instruction word – Wikipedia

By using this site, you agree to the Terms of Use and Privacy Policy. This is known as the modulo constraint and is the source of the term modulo scheduling. Back-end compiler and assembler flow depicting the compression of instructions. For example, if a first instruction’s result is used as a second instruction’s input, then they cannot execute at the same time and the second instruction cannot execute before the first. The Cydra 5 architecture was a VLIW system that was designed epi optimizing the execution of inner loops using software pipelining.

The vliiw is that the prolog and epilog code can neither be customized nor overlapped with surrounding instructions. Fisher’s second innovation was the notion that the target CPU architecture should be designed to be a reasonable target for a compiler; that the compiler and the architecture for a VLIW processor must be codesigned.


This eliminates the NOP that often occurs after a load instruction in control-oriented code. Since determining the order of execution of operations including which operations can execute simultaneously is handled by the compiler, the processor does not need the scheduling hardware that the three methods described above require.

Clearly, software-pipelined loop collapsing and the modulo loop buffer are going to have no effect on the size of control-oriented code. Loop-oriented code benefited more from eliminating the restrictions on spanning execute packets.

He also developed region scheduling methods to identify parallelism beyond basic blocks. VLIW processors are well-suited for high performance embedded applications, which are characterized by mathematically oriented loop kernels and abundant ILP. Assume the compiler determined that ins1 could be safely speculatively executed a second time, but ins2 could not.

A processor that executes every instruction one after the other i. The compiler provides options to select the processor generation and to disable optimization passes that target specific processor features. The loop buffer performs the branch automatically.

Each new fetch packet may contain eight bit instructions a regular fetch packetor contain a mixture of and bit instructions a header-based fetch packet.

The architecture relied heavily on a trace scheduling compiler. Typical bit instruction encoding format. Morgan Kaufmann, December