diff --git a/fsparser.cpp b/fsparser.cpp
new file mode 100644
index 0000000..208775e
--- /dev/null
+++ b/fsparser.cpp
@@ -0,0 +1,140 @@
+/*
+ * Copyright (C) 2019 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include <arpa/inet.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <iostream>
+#include <vector>
+
+#include "fsparser.hpp"
+#include "display.hpp"
+
+using namespace std;
+
+FsParser::FsParser(string filename, bool reverseByte, bool verbose):
+			ConfigBitstreamParser(filename, ConfigBitstreamParser::ASCII_MODE,
+			verbose), _reverseByte(reverseByte), _toolVersion(), _partNumber(),
+			_devicePackage(), _backgroundProgramming(false), _checksum(),
+			_crcCheck(false), _compress(false), _encryption(false),
+			_securityBit(false), _jtagAsRegularIO(false), _date()
+{
+}
+FsParser::~FsParser()
+{
+}
+
+int FsParser::parseHeader()
+{
+	int ret = 1;
+	string buffer;
+
+	while (1){
+		std::getline(_fd, buffer, '\n');
+		if (buffer[0] != '/')
+			break;
+		buffer = buffer.substr(2);
+		size_t pos = buffer.find(':');
+		if (pos == string::npos)
+			continue;
+		string v1, v2;
+		v1 = buffer.substr(0, pos);
+		v2 = buffer.substr(pos+2);  // ':' + ' '
+
+		if (v1 == "GOWIN Version")
+			_toolVersion = v2;
+		if (v1 == "Part Number")
+			_partNumber = v2;
+		if (v1 == "Device-package")
+			_devicePackage = v2;
+		if (v1 == "BackgroundProgramming")
+			_backgroundProgramming = ((v2 == "OFF")?false:true);
+		if (v1 == "CheckSum")
+			sscanf(v2.c_str(), "0x%04hx", &_checksum);
+		if (v1 == "CRCCheck")
+			_crcCheck = ((v2 == "OFF")?false:true);
+		if (v1 == "Compress")
+			_compress = ((v2 == "OFF")?false:true);
+		if (v1 == "Encryption")
+			_encryption = ((v2 == "OFF")?false:true);
+		if (v1 == "SecurityBit")
+			_securityBit = ((v2 == "OFF")?false:true);
+		if (v1 == "JTAGAsRegularIO")
+			_jtagAsRegularIO = ((v2 == "OFF")?false:true);
+		if (v1 == "Created Time")
+			_date = v2;
+	}
+	if (_verbose) {
+		printInfo("tool version:           " +  _toolVersion);
+		printInfo("Part number:            " + _partNumber);
+		printInfo("Device package:         " + _devicePackage);
+		printInfo("Background programming: " +
+				string((_backgroundProgramming)?"ON":"OFF"));
+		printInfo("Checksum:               " + _checksum);
+		printInfo("CRC check:              " + string((_crcCheck)?"ON":"OFF"));
+		printInfo("Compression:            " + string((_compress)?"ON":"OFF"));
+		printInfo("Encryption:             " + string((_encryption)?"ON":"OFF"));
+		printInfo("Security bit:           " + string((_securityBit)?"ON":"OFF"));
+		printInfo("Jtag as regular IO:     " + string((_jtagAsRegularIO)?"ON":"OFF"));
+		printInfo("Creation date:          " + _date);
+	}
+
+	return ret;
+}
+
+int FsParser::parse()
+{
+	uint8_t data;
+	string buffer, tmp;
+
+	printInfo("Parse " + _filename + ": ", false);
+
+	parseHeader();
+	_fd.seekg(0, _fd.beg);
+
+	while (1) {
+		std::getline(_fd, buffer, '\n');
+		if (buffer.size() == 0)
+			break;
+		if (buffer[0] == '/')
+			continue;
+		tmp += buffer;
+	}
+
+	_bit_length = tmp.size();
+
+	/* Fs file format is MSB first
+	 * so if reverseByte = false bit 0 -> 7, 1 -> 6,
+	 * if true 0 -> 0, 1 -> 1
+	 */
+
+	for (int i = 0; i < _bit_length; i+=8) {
+		data = 0;
+		for (int ii = 0; ii < 8; ii++) {
+			uint8_t val = (tmp[i+ii] == '1'?1:0);
+			if (_reverseByte)
+				data |= val << ii;
+			else
+				data |= val << (7-ii);
+		}
+		_bit_data += data;
+	}
+
+	printSuccess("Done");
+
+	return 0;
+}
diff --git a/fsparser.hpp b/fsparser.hpp
new file mode 100644
index 0000000..41bee08
--- /dev/null
+++ b/fsparser.hpp
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2019 Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef FSPARSER_HPP_
+#define FSPARSER_HPP_
+
+#include <fstream>
+#include <iostream>
+#include <string>
+
+#include "configBitstreamParser.hpp"
+
+class FsParser: public ConfigBitstreamParser {
+	public:
+		FsParser(const std::string filename, bool reverseByte, bool verbose);
+		~FsParser();
+		int parse();
+
+		uint16_t checksum() {return _checksum;}
+
+	private:
+		int parseHeader();
+		bool _reverseByte;
+		std::string _toolVersion;
+		std::string _partNumber;
+		std::string _devicePackage;
+		bool _backgroundProgramming;
+		uint16_t _checksum;
+		bool _crcCheck;
+		bool _compress;
+		bool _encryption;
+		bool _securityBit;
+		bool _jtagAsRegularIO;
+		std::string _date;
+};
+
+#endif  // FSPARSER_HPP_