cvw/synthDC

Synthesis for RISC-V Microprocessor System-on-Chip Design

This subdirectory contains synthesis scripts for use with Synopsys (snps) Design Compiler (DC). Synthesis commands are found in scripts/synth.tcl.

Example Usage make synth DESIGN=wallypipelinedcore FREQ=500 CONFIG=rv32e

environment variables

DESIGN Design provides the name of the output log. Default is synth.

FREQ Frequency in MHz. Default is 500

CONFIG The Wally configuration file. The default is rv32e. Examples: rv32e, rv64gc, rv32gc

TECH The target standard cell library. The default is sky130. sky90: skywater 90nm TT 25C sky130: skywater 130nm TT 25C

SAIFPOWER Controls if power analysis is driven by switching factor or RTL modelsim simulation. When enabled requires a saif file named power.saif. The default is 0. 0: switching factor power analysis 1: RTL simulation driven power analysis.

---

Extra Tool (PPA)

To run ppa analysis that hones into target frequency, you can type: python3 ppa/ppaSynth.py from the synthDC directory. This runs a sweep across all modules listed at the bottom of the ppaSynth.py file.

Two options for running the sweep. The first run runs all modules for all techs around a given frequency (i.e., freqs). The second option will run all designs for the specific module based on bestSynths.csv values. Since the second option is 2nd, it has priority. If the second set of values is commented out, it will run all widths.

WARNING: The first option may runs lots of runs that could expend all the licenses available for a license. Therefore, care must be taken to be sure that enough licenses are available for this first option.

Run specific syntheses

widths = [8, 16, 32, 64, 128] 
modules = ['mul', 'adder', 'shifter', 'flop', 'comparator', 'binencoder', 'csa', 'mux2', 'mux4', 'mux8']
techs = ['sky90', 'sky130', 'tsmc28', 'tsmc28psyn']
freqs = [5000]
synthsToRun = allCombos(widths, modules, techs, freqs)

Run a sweep based on best delay found in existing syntheses

module = 'adder'
width = 32
tech = 'tsmc28psyn'
synthsToRun = freqSweep(module, width, tech)