How to Run Cadence Genus ASIC Synthesis

Goal: Run ASIC synthesis using Cadence Genus for an existing ruckus-based project.

Prerequisites

Before running synthesis, ensure the following are in place:

Licensed Cadence Genus installation with the genus binary on PATH
A PDK with liberty (.lib) and LEF (.lef) files
PDK_PATH, STD_CELL_LIB, STD_LEF_LIB, and OPERATING_CONDITION set in the project Makefile
Project Makefile includes system_cadence_genus.mk

Makefile Setup

Add the following to your project Makefile before the ruckus include line. Replace the example paths with your actual PDK installation paths.

export PDK_PATH           = /path/to/pdk
export OPERATING_CONDITION = tt_0p8v_25c
export STD_CELL_LIB       = $(PDK_PATH)/lib/cells.lib
export STD_LEF_LIB        = $(PDK_PATH)/lef/cells.lef

include $(TOP_DIR)/submodules/ruckus/system_cadence_genus.mk

Top-Level ruckus.tcl Structure

Unlike the Vivado build flow (which automatically calls GenBuildString and AnalyzeSrcFileLists internally), the Cadence Genus flow requires you to call these procedures explicitly in your project’s top-level ruckus.tcl. The GenBuildString call generates the build-metadata VHDL package; AnalyzeSrcFileLists passes all source files collected by prior loadRuckusTcl calls to Genus for analysis.

# Load RUCKUS environment and library
source $::env(RUCKUS_QUIET_FLAG) $::env(RUCKUS_PROC_TCL)

# Load ruckus library (ruckus.BuildInfoPkg.vhd only)
GenBuildString $::env(SYN_DIR)

# Load the surf library
loadRuckusTcl "$::env(TOP_DIR)/submodules/surf"

# Load the work library
loadRuckusTcl "$::env(TOP_DIR)/shared"

# Analyze source code loaded into ruckus for Cadence Genus
AnalyzeSrcFileLists

Steps

Run synthesis:
```
make syn
```
This invokes genus -f syn.tcl using the variables you configured above. Synthesis runs with up to MAX_CORES parallel threads (default: 8).
Export a behavioral Verilog netlist (optional):
```
make behavioral_verilog
```
Runs genus -f behavioral_verilog.tcl to export the post-synthesis netlist. Useful for downstream gate-level simulation or handoff to a P&R tool.
Run VCS simulation (if VCS is available):
```
make sim
```
Sources sim.sh to run the VCS simulation flow against the synthesized netlist.

Output Artifacts

After a successful make syn run, outputs are placed in the following locations:

$(OUT_DIR)/syn/ — synthesis working directory
$(OUT_DIR)/syn/out/ — output netlists and reports
$(OUT_DIR)/syn/out/reports/ — timing and area reports
$(OUT_DIR)/syn/out/svf/ — SVF (Scan and Test Verification File)
$(IMAGES_DIR)/ — final promoted artifacts

Key Variables

Variable	Default	Description
`PDK_PATH`	(none)	Path to the PDK root. Must be set by user.
`OPERATING_CONDITION`	(none)	Timing corner name (e.g., `tt_0p8v_25c`). Must be set by user.
`STD_CELL_LIB`	(none)	Standard cell liberty file path (`.lib`). Must be set by user.
`STD_LEF_LIB`	(none)	Standard cell LEF file path (`.lef`). Must be set by user.
`MAX_CORES`	`8`	Number of parallel synthesis cores passed to Genus.
`GIT_BYPASS`	`1`	Git dirty-state check bypassed by default in ASIC flows.

Note

GIT_BYPASS = 1 means the git dirty-state check is disabled by default. ASIC flows typically manage provenance through other mechanisms (e.g., SVF). Set GIT_BYPASS = 0 to re-enable the check if your flow requires it.

See the Makefile Reference for the complete variable reference.

Troubleshooting

“Cannot find liberty file”: Verify that STD_CELL_LIB points to the .lib file itself, not to the PDK root directory. The value should be a full path to a single file, for example $(PDK_PATH)/lib/cells.lib.
“genus: command not found”: Source the Cadence tool setup script for your installation before running make. This is typically a script such as cadence_init.sh or a module load command provided by your site’s EDA environment.