stringread

Simple string read test

This is a simple test for Fletchgen to read strings from an Arrow Recordbatch in simulation.

The files in this folder contain the following:

test.vhd : Accelerator implementation
test.fbs : Schema Flatbuffer file
test.rb  : A RecordBatch based on the schema with some strings (human names)

Running fletchgen with:

fletchgen \
  -i test.fbs \
  -o test_wrapper.vhd  \
  -n test \
  -w test_wrapper \
  -s test.fbs \
  -d test.rb \
  --sim sim_top.vhd \
  -x test.srec

Will produce:

test_wrapper.vhd : Generated wrapper
sim_top.vhd      : Simulation (testbench) top-level
test.srec        : An SREC file for the memory model in simulation.

Now, sim_top.vhd can be simulated. There is a TCL script for QuestaSim:

vsim -do stringread.tcl

After expanding the UserCore wave group in the wave window, you can change the radix of the output data to ASCII and observe the names being streamed into the accelerator core. To change the radix you may issue the TCL command:

property wave -radix ASCII *chars_out_data

In this test, the elements per cycle is set to 4, so we will see the first four characters from right to left, A, l, i and c, on the output: