Updated flow README

Signed-off-by: sakundu <sakundu@ucsd.edu>

Flows/README.md

@@ -25,19 +25,15 @@ Inside each directory are the following sub-directories that contain all of the
   - *scripts* directory contains the setup and scripts to run the full SP&R flow using both commercial and open-source tools.
   - *run* directory to peform the SP&R runs using the runscripts available in the *scripts* direcotry.
 
-We provide the runscripts for all the flows and they are available in the *./\<enablement\>/\<testcase\>/scripts/* directory. The sub-directories available in the scripts directory are as follows.
+The runscripts for all the flows are available in the *./\<enablement\>/\<testcase\>/scripts/* directory. Inside *script* directory are the following sub-directories.
 - *cadence* directory contains all the runscripts related to [Flow-1](./figures/flow-1.PNG), [Flow-2](./figures/flow-2.PNG). We will also add [Flow-4](./figures/flow-4.PNG) scripts here.
-- *OpenROAD* directory contains the *<testcase>.tar.gz* file, which includes all the required file to run [Flow-3](./figures/flow-3.PNG) using OpenROAD-flow-scripts ([ORFS](https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts/tree/master/flow/platforms/nangate45)).
+- *OpenROAD* directory contains the *<testcase>.tar.gz* file, which includes all the required files to run [Flow-3](./figures/flow-3.PNG) using OpenROAD-flow-scripts ([ORFS](https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts/)).
 
-The detailed stpes to run SP&R using the proprietary (commercial) tools **Cadence Genus** (Synthesis) and **Cadence Innovus** (P&R), and the open-source tools **Yosys** (Synthesis) and **OpenROAD** (P&R) are as follows.
-  - [**SP\&R Flow**](#spr-flow)
+All the flows uses the *RTL* from the [*Testcases*](../Testcases/) directory and the *.lef*, *.lib* and *qrc* files from the [*Enablements*](../Enablements/) directory. The required SRAM models for each testcase are generated and also available under the [*Enablements*](../Enablements/) directory. The detailed steps for different tools are as follows.
   - [**Cadence tools**](#using-cadence-genus-and-innovus)
   - [**OpenROAD tools**](#using-openroad-flow-scripts)
   
-## **SP\&R Flow:**
-All the flows uses the *RTL* available under the [*Testcases*](../Testcases/) directory and the *.lef*, *.lib* and *qrc* files available under the [*Enablements*](../Enablements/) directory. All the required SRAM models are generated and available under the [*Enablements*](../Enablements/) directory.    
-  
-### **Using Cadence Genus and Innovus:**
+## **Using Cadence Genus and Innovus:**
 All the required runscripts are available in the *./\<enablement\>/\<testcase\>/scripts/cadence/* directory. The steps to modify *run.sh* to launch SP&R runs for Flow-1 and Flow-2 are as follows.
 - To launch Flow-1 set the **PHY_SYNTH** environment variable to *0* in the *run.sh* file.  
 ``` export PHY_SYNTH=0 ```
@@ -47,50 +43,55 @@ All the required runscripts are available in the *./\<enablement\>/\<testcase\>/
 ``` ./run.sh ```
 
 
-**Synthesis:** The *run_genus_hybrid.tcl* is used to run the logical synthesis using Genus and physical synthesis using Genus iSpatial. It utilizes the **PHY_SYNTH** environment variable to choose which flow to run. Minor details of each synthesis flow are as follows.
-- Logical synthesis using Genus (Flow-1): We use the *elaborate*, *syn_generic*, *syn_map* and *syn_opt* commands to generate the synthesized netlist. This synthesized netlist is available in the *netlist* directory for each testcase on all enablements.
-- Physical synthesis using Genus iSpatial (Flow-2): We use the *elaborate*, *syn_generic -physical*, *syn_map -physical* and *syn_opt -iSpatial* commands to generate the sunthesized netlist. In this step we provide the floorplan def with placed macros and pins as an extra input compared to Flow-1. This def file is generate in Flow-1.
-- Physical synthesis using Genus iSpatial for Circuit Training (Flow-4): This is same as Flow-2 synthesis flow. Only difference is the input def file contains only place pin information and no macro information.
+**Synthesis:** The *run_genus_hybrid.tcl* is used to run the logical synthesis using Genus and physical synthesis using Genus iSpatial. It utilizes the **PHY_SYNTH** environment variable to determine the flow. Minor details of each synthesis flow are as follows.
+- Logical synthesis using Genus (Flow-1): We use the *elaborate*, *syn_generic*, *syn_map* and *syn_opt* commands to generate the synthesized netlist. This synthesized netlist is copied into the *netlist* directory.
+- Physical synthesis using Genus iSpatial (Flow-2): We use the *elaborate*, *syn_generic -physical*, *syn_map -physical* and *syn_opt -iSpatial* commands to generate the sunthesized netlist. In this step we provide the floorplan def with placed macros and pins as an additional input compared to Flow-1. This def file is generate in Flow-1.
+- Physical synthesis using Genus iSpatial for Circuit Training (Flow-4): This is same as Flow-2 synthesis flow. The only difference is that the input def file does not include macro placement information.
 
-The command to launch only the synthesis job is as follows.
+The command to launch only the synthesis run is as follows.
 ```
 # export PHY_SYNTH=0   #For Flow-1 uncomment this line
 # export PHY_SYNTH=1   #For Flow-2 uncomment this line
 genus -overwrite -log log/genus.log -no_gui -files run_genus_hybrid.tcl
 ```  
-We use the constraint file available in the *constraint* directory for the synthesis run. We set the target clock period to a reasonable value that is not too easy or hard for the tool to achieve.
+<!-- We use the constraint file available in the *constraint* directory for the synthesis run. We set the target clock period to a reasonable value that is not too easy or hard for the tool to achieve. -->
 
 **P\&R:** The *run_invs.tcl* is used to run the place and route using Cadence Innovus. The netlist and constraint generated during synthesis flow are used in this step. It also utilizes the **PHY_SYNTH** environment variable to choose which flow to run. Minor details of each P&R flow are as follows.
 - Flow-1
-  - We use aspect ratio 1 and a utilization value in the range of 40% to 60%. All the pins are placed on the left side of the floorplan and the def file *\<design\>_fp.def* is available in the def directory. The following command is used to place the pins.  
+  - We use aspect ratio 1 and a utilization value in the range of 40% to 60%. All the pins are placed on the left side of the floorplan and the floorplan def file *\<design\>_fp.def* is created and copied into the def directory for place and route. The following command is used to place the pins.  
   ```
   ### pin_list contains the name of all the top level pins. Here Y1 < Y2. LAYER1 and LAYER2 are two horizontal layer above M1 or metal1 or met1 ###
   editPin -pin $pin_list -edge 0 -start {0 Y1} -end {0 Y2} -fixedPin -layer {LAYER1 LAYER2} -spreadDirection clockwise -pattern fill_optimised
   ```
-  - The *place_design -concurrent_macros* command is used to place the macros and the def file *\<design\>_fp_placed_macros.def* is available in the def directory.
+  - We use default HALO width based on the enablement for all the macros using the following command.  
+  ```
+  ### HALO_WIDTH is 2um for ASAP7 and 5um for NanGate45 and SKY130HD FakeStack enablements ###
+  addHaloToBlock -allMacro $HALO_WIDTH $HALO_WIDTH $HALO_WIDTH $HALO_WIDTH
+  ```
+  - The *place_design -concurrent_macros* command is used to place the macros and the def file *\<design\>_fp_placed_macros.def* is created and copied into the def directory for synthesis using Flow-2.
   - It uses *place_opt_design*, *ccopt_design* and *routeDesign* commands for placement, CTS and routing of the design.
 - Flow-2
   - The *run_invs.tcl* script utilizes the *.def* file generated by the Genus iSpatial flow as a starting point.
   - Similar to Flow-1 it uses *place_opt_design*, *ccopt_design* and *routeDesign* commands for placement, CTS and routing of the design.
 
-The command to launch the SP&R job is as follows.  
+The command to launch the P&R run is as follows.  
 ```
-### Make sure you have ran the synthesis already. run_invs.tcl uses the output generated in synthesis stage ###
+### Make sure you have run the synthesis synthesis step. run_invs.tcl uses the output files generated synthesis ###
 # export PHY_SYNTH=0   #For Flow-1 uncomment this line
 # export PHY_SYNTH=1   #For Flow-2 uncomment this line
 innovus -64 -init run_invs.tcl -log log/run.log
 ```  
 
-Below is the screenshot of the Ariane SP\&R database with 136 memory macros using Cadence flow on NanGate45 enablement.  
+The screenshot of the Ariane 136 testcase using the Cadence Flow-1 on NanGate45 enablement is given below.  
 <img src="./NanGate45/ariane136/screenshots/Ariane136_Innovus_Genus.png" alt="ariane136_cadence" width="400"/>
 
 This script was written and developed by ABKGroup students at UCSD; however, the underlying commands and reports are copyrighted by Cadence. We thank Cadence for granting permission to share our research to help promote and foster the next generation of innovators.  
 
-### **Using OpenROAD-flow-scripts:**
-Clone ORFS and build OpenROAD tools following the steps given [here](https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts). To run SP&R using OpenROAD tools follow the below mentioned steps:  
+## **Using OpenROAD-flow-scripts:**
+Clone ORFS and build OpenROAD tools following the steps given [here](https://github.com/The-OpenROAD-Project/OpenROAD-flow-scripts). Use the following steps to run SP&R using OpenROAD tools:  
 1. Copy *./\<enablement\>/\<testcase\>/scripts/OpenROAD/\<design\>.tar.gz* file to *{ORFS Clone Directory}/OpenROAD-flow-scripts/flow/designs/\<enablement\>* area.
-2. Use command *tar -xvf \<design\>.tar.gz* to untar *\<design\>.tar.gz*. This will generate *\<design\>* directory which contains all the files required to run SP&R using ORFS.
-3. To launch the SP&R job go to the flow directory and use the below command
+2. Use the command *tar -xvf \<design\>.tar.gz* to untar *\<design\>.tar.gz*. This will generate *\<design\>* directory which contains all the files required to run SP&R using ORFS.
+3. To launch the SP&R job go to the flow directory and use the make command
   ```
   make DESIGN_CONFIG=./designs/<enablement>/<design>/config_hier.mk
   ```
@@ -99,5 +100,5 @@ Clone ORFS and build OpenROAD tools following the steps given [here](https://git
   make DESIGN_CONFIG=./designs/<enablement>/<design>/config.mk
   ```
   
-Below is the screenshot of the Ariane SP\&R database with 136 memory macros using the ORFS (RTL-MP) flow.  
+The screenshot of the Ariane 136 testcase using the ORFS (RTL-MP) on NanGate45 enablement is given below.  
 <img src="./NanGate45/ariane136/screenshots/Ariane136_ORFS_SPNR.png" alt="ariane136_orfs" width="400"/>
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