From 9e893369c9d00c130a018a1a023647a2d9f9d22f Mon Sep 17 00:00:00 2001
From: Cassie Jones <code@witchoflight.com>
Date: Sat, 7 Mar 2020 00:10:53 +0100
Subject: [PATCH] Add -retime and -pre-flatten args

These are the synthesis options that I wanted to be able to run when I
added the -nosynth option, so I'm including them here.
---
 nangate.cc | 37 ++++++++++++++++++++++++++-----------
 1 file changed, 26 insertions(+), 11 deletions(-)

diff --git a/nangate.cc b/nangate.cc
index de0111a..70df222 100644
--- a/nangate.cc
+++ b/nangate.cc
@@ -213,19 +213,25 @@ struct SynthNaN : public Pass {
         log("");
         log("This command synthesizes a design into NaN gates.");
         log("");
+        log("    -nosynth <width>");
+        log("        skip the pre-run synthesis step. Requires that the circuit");
+        log("        has already been synthesized down to NAND and NOT gates.");
+        log("");
+        log("    -pre-flatten");
+        log("        flatten duing the initial coarse synthesis");
+        log("");
+        log("    -retime");
+        log("        do retiming in ABC");
+        log("");
         log("    -top <module>");
         log("        use the specified module as top module (default='top')");
         log("");
         log("    -width <width>");
         log("        synthesize with a given floating-point with (default=3)");
         log("");
-        log("    -nosynth <width>");
-        log("        skip the pre-run synthesis step. Requires that the circuit");
-        log("        has already been synthesized down to NAND and NOT gates.");
-        log("");
         log("Runs the equivalent of the following script:\n\n");
-        log("    synth [-top <module>]          (unless -nosynth)\n");
-        log("    abc -g NAND                    (unless -nosynth)\n");
+        log("    synth [-flatten] [-top <module>]  (unless -nosynth)\n");
+        log("    abc -g NAND [-dff -D 1]           (unless -nosynth)\n");
         log("    nand_to_nan [-width <width>]\n");
         log("    share_nan\n");
         log("    dff_nan [-width <width>]\n");
@@ -234,6 +240,7 @@ struct SynthNaN : public Pass {
         log("    techmap_nan\n");
     }
     void execute(vector <string> args, Design *design) override {
+        string abc_args;
         string synth_args;
         string width_args;
         log_header(design, "Executing SYNTH_NaN pass (synthesizing to tom7 logic).\n");
@@ -242,6 +249,18 @@ struct SynthNaN : public Pass {
         size_t argidx = 1;
         bool synth = true;
         for (; argidx < args.size(); ++argidx) {
+            if (args[argidx] == "-nosynth") {
+                synth = false;
+                continue;
+            }
+            if (args[argidx] == "-pre-flatten") {
+                synth_args += " -flatten";
+                continue;
+            }
+            if (args[argidx] == "-retime") {
+                abc_args += " -dff -D 1";
+                continue;
+            }
             if (args[argidx] == "-top" and argidx + 1 < args.size()) {
                 synth_args += " -top ";
                 synth_args += args[++argidx];
@@ -252,17 +271,13 @@ struct SynthNaN : public Pass {
                 width_args += args[++argidx];
                 continue;
             }
-            if (args[argidx] == "-nosynth") {
-                synth = false;
-                continue;
-            }
             break;
         }
         extra_args(args, argidx, design, false);
 
         if (synth) {
             Pass::call(design, "synth" + synth_args);
-            Pass::call(design, "abc -g NAND");
+            Pass::call(design, "abc -g NAND" + abc_args);
         }
         Pass::call(design, "nand_to_nan" + width_args);
         Pass::call(design, "share_nan");
-- 
2.43.2