1 files changed, 25 insertions, 11 deletions

diff --git a/passes/fsm/fsm_recode.cc b/passes/fsm/fsm_recode.cc
index 5a4e091cf..873ee7a16 100644
--- a/passes/fsm/fsm_recode.cc
+++ b/passes/fsm/fsm_recode.cc
@@ -23,8 +23,9 @@
 #include "kernel/consteval.h"
 #include "kernel/celltypes.h"
 #include "fsmdata.h"
-#include "math.h"
+#include <math.h>
 #include <string.h>
+#include <errno.h>
 
 static void fm_set_fsm_print(RTLIL::Cell *cell, RTLIL::Module *module, FsmData &fsm_data, const char *prefix, FILE *f)
 {
@@ -52,10 +53,10 @@ static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fs
 	std::string encoding = cell->attributes.count("\\fsm_encoding") ? cell->attributes.at("\\fsm_encoding").decode_string() : "auto";
 
 	log("Recoding FSM `%s' from module `%s' using `%s' encoding:\n", cell->name.c_str(), module->name.c_str(), encoding.c_str());
-	if (encoding != "none" && encoding != "one-hot" && encoding != "binary") {
-		if (encoding != "auto")
-			log("  unkown encoding `%s': using auto (%s) instead.\n", encoding.c_str(), default_encoding.c_str());
-		encoding = default_encoding;
+
+	if (encoding != "none" && encoding != "one-hot" && encoding != "binary" && encoding != "auto") {
+		log("  unknown encoding `%s': using auto instead.\n", encoding.c_str());
+		encoding = "auto";
 	}
 
 	if (encoding == "none") {
@@ -69,11 +70,24 @@ static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fs
 	if (fm_set_fsm_file != NULL)
 		fm_set_fsm_print(cell, module, fsm_data, "r", fm_set_fsm_file);
 
+	if (encoding == "auto") {
+		if (!default_encoding.empty())
+			encoding = default_encoding;
+		else
+			encoding = SIZE(fsm_data.state_table) < 32 ? "one-hot" : "binary";
+		log("  mapping auto encoding to `%s` for this FSM.\n", encoding.c_str());
+	}
+
 	if (encoding == "one-hot") {
 		fsm_data.state_bits = fsm_data.state_table.size();
 	} else
-	if (encoding == "auto" || encoding == "binary") {
-		fsm_data.state_bits = ceil(log2(fsm_data.state_table.size()));
+	if (encoding == "binary") {
+		int new_num_state_bits = ceil(log2(fsm_data.state_table.size()));
+		if (fsm_data.state_bits == new_num_state_bits) {
+			log("  existing encoding is already a packed binary encoding.\n");
+			return;
+		}
+		fsm_data.state_bits = new_num_state_bits;
 	} else
 		log_error("FSM encoding `%s' is not supported!\n", encoding.c_str());
 	
@@ -87,7 +101,7 @@ static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fs
 			new_code = RTLIL::Const(RTLIL::State::Sa, fsm_data.state_bits);
 			new_code.bits[state_idx] = RTLIL::State::S1;
 		} else
-		if (encoding == "auto" || encoding == "binary") {
+		if (encoding == "binary") {
 			new_code = RTLIL::Const(state_idx, fsm_data.state_bits);
 		} else
 			log_abort();
@@ -123,7 +137,7 @@ struct FsmRecodePass : public Pass {
 	virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
 	{
 		FILE *fm_set_fsm_file = NULL;
-		std::string default_encoding = "one-hot";
+		std::string default_encoding;
 
 		log_header("Executing FSM_RECODE pass (re-assigning FSM state encoding).\n");
 		size_t argidx;
@@ -143,9 +157,9 @@ struct FsmRecodePass : public Pass {
 		}
 		extra_args(args, argidx, design);
 
-		for (auto &mod_it : design->modules)
+		for (auto &mod_it : design->modules_)
 			if (design->selected(mod_it.second))
-				for (auto &cell_it : mod_it.second->cells)
+				for (auto &cell_it : mod_it.second->cells_)
 					if (cell_it.second->type == "$fsm" && design->selected(mod_it.second, cell_it.second))
 						fsm_recode(cell_it.second, mod_it.second, fm_set_fsm_file, default_encoding);