A Hamming distance Based VLIW/EPIC Code Compression Technique
Speaker: Montse Ros, ITEE
When: 2004-09-16 12:00:00
Venue: 78-420
Host: Dr Peter Sutton
Abstract:This paper presents and reports on a VLIW code compression technique
based on vector Hamming distances. It investigates the appropriate
selection of dictionary vectors such that all program vectors are at
most a specified maximum Hamming distance from a dictionary vector.
Bit toggling information is used to restore the original vector. A
dictionary vector selection method which considered both vector
frequency as well as maximum coverage achieved better results than
just considering vector frequency or vector coverage
independently. This method was found to outperform standard
dictionary compression on TI TMS320C6x program code by an average of
8%, giving compression ratios of 72.1% to 80.3% when applied to the
smallest compiler builds. The most favorable results were achieved
with a Hamming distance upper limit of 3. An investigation into
parallel compression showed that dividing the program into 32-bit
parallel streams returned an average compression ratio of 79.4% for
files larger than 200kb. This approach enables parallel
decompression of instruction streams within a VLIW instruction
word. Suggestions for further work include compiler/compression
integration, more sophisticated dictionary selection methods and
better codeword allocation
Biography:Montse Ros is a confirmed phd student in the School of ITEE at UQ
and is a recipient of the UQ Postgraduate Research Scholarship.
This talk will be presented at the International Conference on
Compilers, Architecture and Synthesis for Embedded Systems. Her
research interests include the application of pure mathematics
(particularly coding theory and cryptography) to hardware and
software, as well as computer architecture and digital design. Her
research topic aims to combine some of these areas.
Type: ESG
Contact:Dr Peter Sutton, seminar host (p.sutton@itee.uq.edu.au)
or Guido Governatori (ITEE seminar co-ordinator)
(guido@itee.uq.edu.au)