Subversion Repositories reedsolomon

Reed-Solomon decoder design for C-based synthesis

Top level decoder module: rs_decode.cpp
Simple Testbench: test_rs_decode.cpp

Presently dynamic values of k and t are not used in the decoding process. 
Instead the static constants in global_rs.h are used for simplicity.

Executing make compiles the decoder and the testbench and creates an executable.
Correct execution is indicated by the decoded output being a descending count 
from 223 to 1, repeated 3 times.

For synthesis, import into a C based design tool, set appropriate HW parameters
and synthesize for a particular platform.

For our case study of generating hardware from this code, the following
transformations and directives were used for improving performance:

- Break up complex functions into smaller & simpler computational
  segments/loops to allow independent optimizations, for example see
  berlekamp.cpp, each loop labelled for further directives.

- Modify loops dependent on dynamic bounds to use static bounds and
  mask output to give correct result.

- Unroll 'For' loops with fixed static bounds maximally, marked in
  code as comments corresponding to each loop to be unrolled. Loops
  unrolled in berlekamp.cpp, chien_search.cpp, gf_arith.cpp,
  syndrome.cpp.

- Synthesize hardware units for individual functions rather than the
  entire logic as a single unit, marked in code as comments for
  independent synthesis. 

- Use appropriate streaming buffers for communication between
  functional units. Buffers should allow fine-grained pipeline
  parallelism across a single data block where possible.