Crossbar-Design

Design and Evaluation of Accelerator Organizations for Binarzed Neural Networks

Requirements

GHDL
GTKWave
VHDL
VIVADO

Quick Instruction

To simulate in VIVADO (Execution Time)

Add the controller_tb.vhdl file as a simulation source
Add the constraint.xdc file as a constraint
Add all the other VHDL files to the VIVADO as design source
Start Simulation

To check the Energy and register area (Luts and flip flops) in VIVADO

The same for Simulation but:

All the BUSs and ROMs and the simulation file controller_tb.vhdl should be disabled and
Their calls in Controller.vhdl component should also been disabled (rermoved or commented)

Cloning repository

  $ git clone https://github.com/somar0/Crossbar-Design.git
  $ cd Crossbar-Design
  $ cd Strided Move
  or
  $ cd Vertical Move

Compiling VHDL code and looking on wave diagrams in GTKWave

  $ ghdl -s test_file.vhdl                 #Syntax Check  
  $ ghdl -a test_file.vhdl                 #Analyse  
  $ ghdl -e test_file.vhdl                 #Build   
  $ ghdl -r test_file --vcd=testbench.vcd  #VCD-Dump  
  $ gtkwave testbench.vcd                  #Start GTKWave

Auto compiling the project

In each design file there is a script to compile all the components automatically. You can use it like this:
```
$ sh compile_sm.sh
or
$ sh compile_vm.sh
```

Python file:

  To check the correctness of the Results.
  The values for the input, weights, and thresholds matrices are here generated and stored in the files;
  inputs.txt, weights.txt and threshold.txt, respectively.
  The generated values are the same every time so we can compare the results.
  They can be changed through the Python script but then the ROMs value should be modified with the new values 
  The final results from python script are stored in the file activations.txt in binary
  The results are converted from binary to hexadecimal (not through the python script) in file activations_hexadecimal.txt
  to easialy compare the results with the simulation results

P.S.:

  The input matrix has been through the Python script transposed after generating its values
  so the columns became rwos and the rows became columns in the inputs.txt file,
  so we could write them as they are in the data_rom.vhdl 
  to deal with its original columns as rows (std_logic_vector) in VHDL.
  
  When changing the configuration in pkg.vhdl, we need to modify the time in controller_tb.vhdl.

System Model:

pkg.vhdl

Configuration component where we define the input, weights and threshold matrices's sizes 
and where we can change the configurations; 
(m, n) the number of (columns, XNORs) in the the crossbar array

controller.vhdl

Controller to control the data flow between the components

weights_rom.vhdl & data_rom.vhdl & threshold_rom.vhdl
```
ROMs to store the three matrices's values
```

weights_bus.vhdl & data_bus.vhdl & threshold_bus.vhdl

BUSs to control which rows are bieng read from the three ROMs

SM.vhdl & VM.vhdl

Components to differentiate between strided move and vertical move

CB.vhdl

Crossbar component which has the columns and the interface circuit
Accumulator and comparator components are also in CB components

column.vhdl

Column to calculate the multiplication between weights and inputs through the XNORs gates

cb_xnor.vhdl

XNOR gate that takes two bits as inputs

ic.vhdl

Interface circuit components which has the popcount
Accumulator and comparator aren't in the interface circuit because results in accumulator 
and comparator need to be stored longer than in XNORs and popcount.

popcount.vhdl

Popcount to count how many ones in the resulting vector from XNOR gates.
It has many adders and flip flops components

cb_adder.vhdl

Adder To add two vectors of a given size through generic

cb_dff.vhdl

D-flip flop to register a vector of a given size through generic

acc.vhdl

Accumulator to accumulate the popcount results (partial sums)

comparator.vhdl

Comparator to compare the final result of the accumulator with the appropriate threshold value

controller_tb.vhdl

Simulation file where we can control how long will the design run

myay / Crossbar-Design