kernel/calc.cc - third_party/yosys - Git at Google

 /*
  *  yosys -- Yosys Open SYnthesis Suite
  *
  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
  *
  *  Permission to use, copy, modify, and/or distribute this software for any
  *  purpose with or without fee is hereby granted, provided that the above
  *  copyright notice and this permission notice appear in all copies.
  *
  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  *
  */

 // [[CITE]] Power-Modulus Algorithm
 // Schneier, Bruce (1996). Applied Cryptography: Protocols, Algorithms, and Source Code in C,
 // Second Edition (2nd ed.). Wiley. ISBN 978-0-471-11709-4, page 244

 #include "kernel/yosys.h"
 #include "libs/bigint/BigIntegerLibrary.hh"

 YOSYS_NAMESPACE_BEGIN

 static void extend_u0(RTLIL::Const &arg, int width, bool is_signed)
 {
 	RTLIL::State padding = RTLIL::State::S0;

 	if (arg.bits.size() > 0 && is_signed)
 		padding = arg.bits.back();

 	while (int(arg.bits.size()) < width)
 		arg.bits.push_back(padding);

 	arg.bits.resize(width);
 }

 static BigInteger const2big(const RTLIL::Const &val, bool as_signed, int &undef_bit_pos)
 {
 	BigUnsigned mag;

 	BigInteger::Sign sign = BigInteger::positive;
 	State inv_sign_bit = RTLIL::State::S1;
 	size_t num_bits = val.bits.size();

 	if (as_signed && num_bits && val.bits[num_bits-1] == RTLIL::State::S1) {
 		inv_sign_bit = RTLIL::State::S0;
 		sign = BigInteger::negative;
 		num_bits--;
 	}

 	for (size_t i = 0; i < num_bits; i++)
 		if (val.bits[i] == RTLIL::State::S0 || val.bits[i] == RTLIL::State::S1)
 			mag.setBit(i, val.bits[i] == inv_sign_bit);
 		else if (undef_bit_pos < 0)
 			undef_bit_pos = i;

 	if (sign == BigInteger::negative)
 		mag += 1;

 	return BigInteger(mag, sign);
 }

 static RTLIL::Const big2const(const BigInteger &val, int result_len, int undef_bit_pos)
 {
 	if (undef_bit_pos >= 0)
 		return RTLIL::Const(RTLIL::State::Sx, result_len);

 	BigUnsigned mag = val.getMagnitude();
 	RTLIL::Const result(0, result_len);

 	if (!mag.isZero())
 	{
 		if (val.getSign() < 0)
 		{
 			mag--;
 			for (int i = 0; i < result_len; i++)
 				result.bits[i] = mag.getBit(i) ? RTLIL::State::S0 : RTLIL::State::S1;
 		}
 		else
 		{
 			for (int i = 0; i < result_len; i++)
 				result.bits[i] = mag.getBit(i) ? RTLIL::State::S1 : RTLIL::State::S0;
 		}
 	}

 #if 0
 	if (undef_bit_pos >= 0)
 		for (int i = undef_bit_pos; i < result_len; i++)
 			result.bits[i] = RTLIL::State::Sx;
 #endif

 	return result;
 }

 static RTLIL::State logic_and(RTLIL::State a, RTLIL::State b)
 {
 	if (a == RTLIL::State::S0) return RTLIL::State::S0;
 	if (b == RTLIL::State::S0) return RTLIL::State::S0;
 	if (a != RTLIL::State::S1) return RTLIL::State::Sx;
 	if (b != RTLIL::State::S1) return RTLIL::State::Sx;
 	return RTLIL::State::S1;
 }

 static RTLIL::State logic_or(RTLIL::State a, RTLIL::State b)
 {
 	if (a == RTLIL::State::S1) return RTLIL::State::S1;
 	if (b == RTLIL::State::S1) return RTLIL::State::S1;
 	if (a != RTLIL::State::S0) return RTLIL::State::Sx;
 	if (b != RTLIL::State::S0) return RTLIL::State::Sx;
 	return RTLIL::State::S0;
 }

 static RTLIL::State logic_xor(RTLIL::State a, RTLIL::State b)
 {
 	if (a != RTLIL::State::S0 && a != RTLIL::State::S1) return RTLIL::State::Sx;
 	if (b != RTLIL::State::S0 && b != RTLIL::State::S1) return RTLIL::State::Sx;
 	return a != b ? RTLIL::State::S1 : RTLIL::State::S0;
 }

 static RTLIL::State logic_xnor(RTLIL::State a, RTLIL::State b)
 {
 	if (a != RTLIL::State::S0 && a != RTLIL::State::S1) return RTLIL::State::Sx;
 	if (b != RTLIL::State::S0 && b != RTLIL::State::S1) return RTLIL::State::Sx;
 	return a == b ? RTLIL::State::S1 : RTLIL::State::S0;
 }

 RTLIL::Const RTLIL::const_not(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
 {
 	if (result_len < 0)
 		result_len = arg1.bits.size();

 	RTLIL::Const arg1_ext = arg1;
 	extend_u0(arg1_ext, result_len, signed1);

 	RTLIL::Const result(RTLIL::State::Sx, result_len);
 	for (size_t i = 0; i < size_t(result_len); i++) {
 		if (i >= arg1_ext.bits.size())
 			result.bits[i] = RTLIL::State::S0;
 		else if (arg1_ext.bits[i] == RTLIL::State::S0)
 			result.bits[i] = RTLIL::State::S1;
 		else if (arg1_ext.bits[i] == RTLIL::State::S1)
 			result.bits[i] = RTLIL::State::S0;
 	}

 	return result;
 }

 static RTLIL::Const logic_wrapper(RTLIL::State(*logic_func)(RTLIL::State, RTLIL::State),
 		RTLIL::Const arg1, RTLIL::Const arg2, bool signed1, bool signed2, int result_len = -1)
 {
 	if (result_len < 0)
 		result_len = max(arg1.bits.size(), arg2.bits.size());

 	extend_u0(arg1, result_len, signed1);
 	extend_u0(arg2, result_len, signed2);

 	RTLIL::Const result(RTLIL::State::Sx, result_len);
 	for (size_t i = 0; i < size_t(result_len); i++) {
 		RTLIL::State a = i < arg1.bits.size() ? arg1.bits[i] : RTLIL::State::S0;
 		RTLIL::State b = i < arg2.bits.size() ? arg2.bits[i] : RTLIL::State::S0;
 		result.bits[i] = logic_func(a, b);
 	}

 	return result;
 }

 RTLIL::Const RTLIL::const_and(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	return logic_wrapper(logic_and, arg1, arg2, signed1, signed2, result_len);
 }

 RTLIL::Const RTLIL::const_or(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	return logic_wrapper(logic_or, arg1, arg2, signed1, signed2, result_len);
 }

 RTLIL::Const RTLIL::const_xor(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	return logic_wrapper(logic_xor, arg1, arg2, signed1, signed2, result_len);
 }

 RTLIL::Const RTLIL::const_xnor(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	return logic_wrapper(logic_xnor, arg1, arg2, signed1, signed2, result_len);
 }

 static RTLIL::Const logic_reduce_wrapper(RTLIL::State initial, RTLIL::State(*logic_func)(RTLIL::State, RTLIL::State), const RTLIL::Const &arg1, int result_len)
 {
 	RTLIL::State temp = initial;

 	for (size_t i = 0; i < arg1.bits.size(); i++)
 		temp = logic_func(temp, arg1.bits[i]);

 	RTLIL::Const result(temp);
 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 RTLIL::Const RTLIL::const_reduce_and(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
 {
 	return logic_reduce_wrapper(RTLIL::State::S1, logic_and, arg1, result_len);
 }

 RTLIL::Const RTLIL::const_reduce_or(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
 {
 	return logic_reduce_wrapper(RTLIL::State::S0, logic_or, arg1, result_len);
 }

 RTLIL::Const RTLIL::const_reduce_xor(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
 {
 	return logic_reduce_wrapper(RTLIL::State::S0, logic_xor, arg1, result_len);
 }

 RTLIL::Const RTLIL::const_reduce_xnor(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
 {
 	RTLIL::Const buffer = logic_reduce_wrapper(RTLIL::State::S0, logic_xor, arg1, result_len);
 	if (!buffer.bits.empty()) {
 		if (buffer.bits.front() == RTLIL::State::S0)
 			buffer.bits.front() = RTLIL::State::S1;
 		else if (buffer.bits.front() == RTLIL::State::S1)
 			buffer.bits.front() = RTLIL::State::S0;
 	}
 	return buffer;
 }

 RTLIL::Const RTLIL::const_reduce_bool(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
 {
 	return logic_reduce_wrapper(RTLIL::State::S0, logic_or, arg1, result_len);
 }

 RTLIL::Const RTLIL::const_logic_not(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
 {
 	int undef_bit_pos_a = -1;
 	BigInteger a = const2big(arg1, signed1, undef_bit_pos_a);
 	RTLIL::Const result(a.isZero() ? undef_bit_pos_a >= 0 ? RTLIL::State::Sx : RTLIL::State::S1 : RTLIL::State::S0);

 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 RTLIL::Const RTLIL::const_logic_and(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos_a = -1, undef_bit_pos_b = -1;
 	BigInteger a = const2big(arg1, signed1, undef_bit_pos_a);
 	BigInteger b = const2big(arg2, signed2, undef_bit_pos_b);

 	RTLIL::State bit_a = a.isZero() ? undef_bit_pos_a >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
 	RTLIL::State bit_b = b.isZero() ? undef_bit_pos_b >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
 	RTLIL::Const result(logic_and(bit_a, bit_b));

 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 RTLIL::Const RTLIL::const_logic_or(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos_a = -1, undef_bit_pos_b = -1;
 	BigInteger a = const2big(arg1, signed1, undef_bit_pos_a);
 	BigInteger b = const2big(arg2, signed2, undef_bit_pos_b);

 	RTLIL::State bit_a = a.isZero() ? undef_bit_pos_a >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
 	RTLIL::State bit_b = b.isZero() ? undef_bit_pos_b >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
 	RTLIL::Const result(logic_or(bit_a, bit_b));

 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 static RTLIL::Const const_shift_worker(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool sign_ext, int direction, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger offset = const2big(arg2, false, undef_bit_pos) * direction;

 	if (result_len < 0)
 		result_len = arg1.bits.size();

 	RTLIL::Const result(RTLIL::State::Sx, result_len);
 	if (undef_bit_pos >= 0)
 		return result;

 	for (int i = 0; i < result_len; i++) {
 		BigInteger pos = BigInteger(i) + offset;
 		if (pos < 0)
 			result.bits[i] = RTLIL::State::S0;
 		else if (pos >= BigInteger(int(arg1.bits.size())))
 			result.bits[i] = sign_ext ? arg1.bits.back() : RTLIL::State::S0;
 		else
 			result.bits[i] = arg1.bits[pos.toInt()];
 	}

 	return result;
 }

 RTLIL::Const RTLIL::const_shl(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;
 	extend_u0(arg1_ext, result_len, signed1);
 	return const_shift_worker(arg1_ext, arg2, false, -1, result_len);
 }

 RTLIL::Const RTLIL::const_shr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;
 	extend_u0(arg1_ext, max(result_len, GetSize(arg1)), signed1);
 	return const_shift_worker(arg1_ext, arg2, false, +1, result_len);
 }

 RTLIL::Const RTLIL::const_sshl(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	if (!signed1)
 		return const_shl(arg1, arg2, signed1, signed2, result_len);
 	return const_shift_worker(arg1, arg2, true, -1, result_len);
 }

 RTLIL::Const RTLIL::const_sshr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	if (!signed1)
 		return const_shr(arg1, arg2, signed1, signed2, result_len);
 	return const_shift_worker(arg1, arg2, true, +1, result_len);
 }

 static RTLIL::Const const_shift_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool, bool signed2, int result_len, RTLIL::State other_bits)
 {
 	int undef_bit_pos = -1;
 	BigInteger offset = const2big(arg2, signed2, undef_bit_pos);

 	if (result_len < 0)
 		result_len = arg1.bits.size();

 	RTLIL::Const result(RTLIL::State::Sx, result_len);
 	if (undef_bit_pos >= 0)
 		return result;

 	for (int i = 0; i < result_len; i++) {
 		BigInteger pos = BigInteger(i) + offset;
 		if (pos < 0 || pos >= BigInteger(int(arg1.bits.size())))
 			result.bits[i] = other_bits;
 		else
 			result.bits[i] = arg1.bits[pos.toInt()];
 	}

 	return result;
 }

 RTLIL::Const RTLIL::const_shift(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::S0);
 }

 RTLIL::Const RTLIL::const_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::Sx);
 }

 RTLIL::Const RTLIL::const_lt(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	bool y = const2big(arg1, signed1, undef_bit_pos) < const2big(arg2, signed2, undef_bit_pos);
 	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 RTLIL::Const RTLIL::const_le(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	bool y = const2big(arg1, signed1, undef_bit_pos) <= const2big(arg2, signed2, undef_bit_pos);
 	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 RTLIL::Const RTLIL::const_eq(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;
 	RTLIL::Const arg2_ext = arg2;
 	RTLIL::Const result(RTLIL::State::S0, result_len);

 	int width = max(arg1_ext.bits.size(), arg2_ext.bits.size());
 	extend_u0(arg1_ext, width, signed1 && signed2);
 	extend_u0(arg2_ext, width, signed1 && signed2);

 	RTLIL::State matched_status = RTLIL::State::S1;
 	for (size_t i = 0; i < arg1_ext.bits.size(); i++) {
 		if (arg1_ext.bits.at(i) == RTLIL::State::S0 && arg2_ext.bits.at(i) == RTLIL::State::S1)
 			return result;
 		if (arg1_ext.bits.at(i) == RTLIL::State::S1 && arg2_ext.bits.at(i) == RTLIL::State::S0)
 			return result;
 		if (arg1_ext.bits.at(i) > RTLIL::State::S1 || arg2_ext.bits.at(i) > RTLIL::State::S1)
 			matched_status = RTLIL::State::Sx;
 	}

 	result.bits.front() = matched_status;
 	return result;
 }

 RTLIL::Const RTLIL::const_ne(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	RTLIL::Const result = RTLIL::const_eq(arg1, arg2, signed1, signed2, result_len);
 	if (result.bits.front() == RTLIL::State::S0)
 		result.bits.front() = RTLIL::State::S1;
 	else if (result.bits.front() == RTLIL::State::S1)
 		result.bits.front() = RTLIL::State::S0;
 	return result;
 }

 RTLIL::Const RTLIL::const_eqx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;
 	RTLIL::Const arg2_ext = arg2;
 	RTLIL::Const result(RTLIL::State::S0, result_len);

 	int width = max(arg1_ext.bits.size(), arg2_ext.bits.size());
 	extend_u0(arg1_ext, width, signed1 && signed2);
 	extend_u0(arg2_ext, width, signed1 && signed2);

 	for (size_t i = 0; i < arg1_ext.bits.size(); i++) {
 		if (arg1_ext.bits.at(i) != arg2_ext.bits.at(i))
 			return result;
 	}

 	result.bits.front() = RTLIL::State::S1;
 	return result;
 }

 RTLIL::Const RTLIL::const_nex(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	RTLIL::Const result = RTLIL::const_eqx(arg1, arg2, signed1, signed2, result_len);
 	if (result.bits.front() == RTLIL::State::S0)
 		result.bits.front() = RTLIL::State::S1;
 	else if (result.bits.front() == RTLIL::State::S1)
 		result.bits.front() = RTLIL::State::S0;
 	return result;
 }

 RTLIL::Const RTLIL::const_ge(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	bool y = const2big(arg1, signed1, undef_bit_pos) >= const2big(arg2, signed2, undef_bit_pos);
 	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 RTLIL::Const RTLIL::const_gt(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	bool y = const2big(arg1, signed1, undef_bit_pos) > const2big(arg2, signed2, undef_bit_pos);
 	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

 	while (int(result.bits.size()) < result_len)
 		result.bits.push_back(RTLIL::State::S0);
 	return result;
 }

 RTLIL::Const RTLIL::const_add(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger y = const2big(arg1, signed1, undef_bit_pos) + const2big(arg2, signed2, undef_bit_pos);
 	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
 }

 RTLIL::Const RTLIL::const_sub(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger y = const2big(arg1, signed1, undef_bit_pos) - const2big(arg2, signed2, undef_bit_pos);
 	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
 }

 RTLIL::Const RTLIL::const_mul(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger y = const2big(arg1, signed1, undef_bit_pos) * const2big(arg2, signed2, undef_bit_pos);
 	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
 }

 RTLIL::Const RTLIL::const_div(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger a = const2big(arg1, signed1, undef_bit_pos);
 	BigInteger b = const2big(arg2, signed2, undef_bit_pos);
 	if (b.isZero())
 		return RTLIL::Const(RTLIL::State::Sx, result_len);
 	bool result_neg = (a.getSign() == BigInteger::negative) != (b.getSign() == BigInteger::negative);
 	a = a.getSign() == BigInteger::negative ? -a : a;
 	b = b.getSign() == BigInteger::negative ? -b : b;
 	return big2const(result_neg ? -(a / b) : (a / b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
 }

 RTLIL::Const RTLIL::const_mod(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;
 	BigInteger a = const2big(arg1, signed1, undef_bit_pos);
 	BigInteger b = const2big(arg2, signed2, undef_bit_pos);
 	if (b.isZero())
 		return RTLIL::Const(RTLIL::State::Sx, result_len);
 	bool result_neg = a.getSign() == BigInteger::negative;
 	a = a.getSign() == BigInteger::negative ? -a : a;
 	b = b.getSign() == BigInteger::negative ? -b : b;
 	return big2const(result_neg ? -(a % b) : (a % b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
 }

 RTLIL::Const RTLIL::const_pow(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
 {
 	int undef_bit_pos = -1;

 	BigInteger a = const2big(arg1, signed1, undef_bit_pos);
 	BigInteger b = const2big(arg2, signed2, undef_bit_pos);
 	BigInteger y = 1;

 	if (a == 0 && b < 0)
 		return RTLIL::Const(RTLIL::State::Sx, result_len);

 	if (a == 0 && b > 0)
 		return RTLIL::Const(RTLIL::State::S0, result_len);

 	if (b < 0)
 	{
 		if (a < -1 || a > 1)
 			y = 0;
 		if (a == -1)
 			y = (-b % 2) == 0 ? 1 : -1;
 	}

 	if (b > 0)
 	{
 		// Power-modulo with 2^result_len as modulus
 		BigInteger modulus = 1;
 		int modulus_bits = (result_len >= 0 ? result_len : 1024);
 		for (int i = 0; i < modulus_bits; i++)
 			modulus *= 2;

 		bool flip_result_sign = false;
 		if (a < 0) {
 			a *= -1;
 			if (b % 2 == 1)
 				flip_result_sign = true;
 		}

 		while (b > 0) {
 			if (b % 2 == 1)
 				y = (y * a) % modulus;
 			b = b / 2;
 			a = (a * a) % modulus;
 		}

 		if (flip_result_sign)
 			y *= -1;
 	}

 	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
 }

 RTLIL::Const RTLIL::const_pos(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;
 	extend_u0(arg1_ext, result_len, signed1);

 	return arg1_ext;
 }

 RTLIL::Const RTLIL::const_neg(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
 {
 	RTLIL::Const arg1_ext = arg1;
 	RTLIL::Const zero(RTLIL::State::S0, 1);

 	return RTLIL::const_sub(zero, arg1_ext, true, signed1, result_len);
 }

 YOSYS_NAMESPACE_END
	/*
	* yosys -- Yosys Open SYnthesis Suite
	*
	* Copyright (C) 2012 Clifford Wolf <clifford@clifford.at>
	*
	* Permission to use, copy, modify, and/or distribute this software for any
	* purpose with or without fee is hereby granted, provided that the above
	* copyright notice and this permission notice appear in all copies.
	*
	* THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
	* WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
	* MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
	* ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
	* WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
	* ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
	* OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
	*
	*/

	// [[CITE]] Power-Modulus Algorithm
	// Schneier, Bruce (1996). Applied Cryptography: Protocols, Algorithms, and Source Code in C,
	// Second Edition (2nd ed.). Wiley. ISBN 978-0-471-11709-4, page 244

	#include "kernel/yosys.h"
	#include "libs/bigint/BigIntegerLibrary.hh"

	YOSYS_NAMESPACE_BEGIN

	static void extend_u0(RTLIL::Const &arg, int width, bool is_signed)
	{
	RTLIL::State padding = RTLIL::State::S0;

	if (arg.bits.size() > 0 && is_signed)
	padding = arg.bits.back();

	while (int(arg.bits.size()) < width)
	arg.bits.push_back(padding);

	arg.bits.resize(width);
	}

	static BigInteger const2big(const RTLIL::Const &val, bool as_signed, int &undef_bit_pos)
	{
	BigUnsigned mag;

	BigInteger::Sign sign = BigInteger::positive;
	State inv_sign_bit = RTLIL::State::S1;
	size_t num_bits = val.bits.size();

	if (as_signed && num_bits && val.bits[num_bits-1] == RTLIL::State::S1) {
	inv_sign_bit = RTLIL::State::S0;
	sign = BigInteger::negative;
	num_bits--;
	}

	for (size_t i = 0; i < num_bits; i++)
	if (val.bits[i] == RTLIL::State::S0 \|\| val.bits[i] == RTLIL::State::S1)
	mag.setBit(i, val.bits[i] == inv_sign_bit);
	else if (undef_bit_pos < 0)
	undef_bit_pos = i;

	if (sign == BigInteger::negative)
	mag += 1;

	return BigInteger(mag, sign);
	}

	static RTLIL::Const big2const(const BigInteger &val, int result_len, int undef_bit_pos)
	{
	if (undef_bit_pos >= 0)
	return RTLIL::Const(RTLIL::State::Sx, result_len);

	BigUnsigned mag = val.getMagnitude();
	RTLIL::Const result(0, result_len);

	if (!mag.isZero())
	{
	if (val.getSign() < 0)
	{
	mag--;
	for (int i = 0; i < result_len; i++)
	result.bits[i] = mag.getBit(i) ? RTLIL::State::S0 : RTLIL::State::S1;
	}
	else
	{
	for (int i = 0; i < result_len; i++)
	result.bits[i] = mag.getBit(i) ? RTLIL::State::S1 : RTLIL::State::S0;
	}
	}

	#if 0
	if (undef_bit_pos >= 0)
	for (int i = undef_bit_pos; i < result_len; i++)
	result.bits[i] = RTLIL::State::Sx;
	#endif

	return result;
	}

	static RTLIL::State logic_and(RTLIL::State a, RTLIL::State b)
	{
	if (a == RTLIL::State::S0) return RTLIL::State::S0;
	if (b == RTLIL::State::S0) return RTLIL::State::S0;
	if (a != RTLIL::State::S1) return RTLIL::State::Sx;
	if (b != RTLIL::State::S1) return RTLIL::State::Sx;
	return RTLIL::State::S1;
	}

	static RTLIL::State logic_or(RTLIL::State a, RTLIL::State b)
	{
	if (a == RTLIL::State::S1) return RTLIL::State::S1;
	if (b == RTLIL::State::S1) return RTLIL::State::S1;
	if (a != RTLIL::State::S0) return RTLIL::State::Sx;
	if (b != RTLIL::State::S0) return RTLIL::State::Sx;
	return RTLIL::State::S0;
	}

	static RTLIL::State logic_xor(RTLIL::State a, RTLIL::State b)
	{
	if (a != RTLIL::State::S0 && a != RTLIL::State::S1) return RTLIL::State::Sx;
	if (b != RTLIL::State::S0 && b != RTLIL::State::S1) return RTLIL::State::Sx;
	return a != b ? RTLIL::State::S1 : RTLIL::State::S0;
	}

	static RTLIL::State logic_xnor(RTLIL::State a, RTLIL::State b)
	{
	if (a != RTLIL::State::S0 && a != RTLIL::State::S1) return RTLIL::State::Sx;
	if (b != RTLIL::State::S0 && b != RTLIL::State::S1) return RTLIL::State::Sx;
	return a == b ? RTLIL::State::S1 : RTLIL::State::S0;
	}

	RTLIL::Const RTLIL::const_not(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
	{
	if (result_len < 0)
	result_len = arg1.bits.size();

	RTLIL::Const arg1_ext = arg1;
	extend_u0(arg1_ext, result_len, signed1);

	RTLIL::Const result(RTLIL::State::Sx, result_len);
	for (size_t i = 0; i < size_t(result_len); i++) {
	if (i >= arg1_ext.bits.size())
	result.bits[i] = RTLIL::State::S0;
	else if (arg1_ext.bits[i] == RTLIL::State::S0)
	result.bits[i] = RTLIL::State::S1;
	else if (arg1_ext.bits[i] == RTLIL::State::S1)
	result.bits[i] = RTLIL::State::S0;
	}

	return result;
	}

	static RTLIL::Const logic_wrapper(RTLIL::State(*logic_func)(RTLIL::State, RTLIL::State),
	RTLIL::Const arg1, RTLIL::Const arg2, bool signed1, bool signed2, int result_len = -1)
	{
	if (result_len < 0)
	result_len = max(arg1.bits.size(), arg2.bits.size());

	extend_u0(arg1, result_len, signed1);
	extend_u0(arg2, result_len, signed2);

	RTLIL::Const result(RTLIL::State::Sx, result_len);
	for (size_t i = 0; i < size_t(result_len); i++) {
	RTLIL::State a = i < arg1.bits.size() ? arg1.bits[i] : RTLIL::State::S0;
	RTLIL::State b = i < arg2.bits.size() ? arg2.bits[i] : RTLIL::State::S0;
	result.bits[i] = logic_func(a, b);
	}

	return result;
	}

	RTLIL::Const RTLIL::const_and(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	return logic_wrapper(logic_and, arg1, arg2, signed1, signed2, result_len);
	}

	RTLIL::Const RTLIL::const_or(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	return logic_wrapper(logic_or, arg1, arg2, signed1, signed2, result_len);
	}

	RTLIL::Const RTLIL::const_xor(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	return logic_wrapper(logic_xor, arg1, arg2, signed1, signed2, result_len);
	}

	RTLIL::Const RTLIL::const_xnor(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	return logic_wrapper(logic_xnor, arg1, arg2, signed1, signed2, result_len);
	}

	static RTLIL::Const logic_reduce_wrapper(RTLIL::State initial, RTLIL::State(*logic_func)(RTLIL::State, RTLIL::State), const RTLIL::Const &arg1, int result_len)
	{
	RTLIL::State temp = initial;

	for (size_t i = 0; i < arg1.bits.size(); i++)
	temp = logic_func(temp, arg1.bits[i]);

	RTLIL::Const result(temp);
	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	RTLIL::Const RTLIL::const_reduce_and(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
	{
	return logic_reduce_wrapper(RTLIL::State::S1, logic_and, arg1, result_len);
	}

	RTLIL::Const RTLIL::const_reduce_or(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
	{
	return logic_reduce_wrapper(RTLIL::State::S0, logic_or, arg1, result_len);
	}

	RTLIL::Const RTLIL::const_reduce_xor(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
	{
	return logic_reduce_wrapper(RTLIL::State::S0, logic_xor, arg1, result_len);
	}

	RTLIL::Const RTLIL::const_reduce_xnor(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
	{
	RTLIL::Const buffer = logic_reduce_wrapper(RTLIL::State::S0, logic_xor, arg1, result_len);
	if (!buffer.bits.empty()) {
	if (buffer.bits.front() == RTLIL::State::S0)
	buffer.bits.front() = RTLIL::State::S1;
	else if (buffer.bits.front() == RTLIL::State::S1)
	buffer.bits.front() = RTLIL::State::S0;
	}
	return buffer;
	}

	RTLIL::Const RTLIL::const_reduce_bool(const RTLIL::Const &arg1, const RTLIL::Const&, bool, bool, int result_len)
	{
	return logic_reduce_wrapper(RTLIL::State::S0, logic_or, arg1, result_len);
	}

	RTLIL::Const RTLIL::const_logic_not(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
	{
	int undef_bit_pos_a = -1;
	BigInteger a = const2big(arg1, signed1, undef_bit_pos_a);
	RTLIL::Const result(a.isZero() ? undef_bit_pos_a >= 0 ? RTLIL::State::Sx : RTLIL::State::S1 : RTLIL::State::S0);

	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	RTLIL::Const RTLIL::const_logic_and(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos_a = -1, undef_bit_pos_b = -1;
	BigInteger a = const2big(arg1, signed1, undef_bit_pos_a);
	BigInteger b = const2big(arg2, signed2, undef_bit_pos_b);

	RTLIL::State bit_a = a.isZero() ? undef_bit_pos_a >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
	RTLIL::State bit_b = b.isZero() ? undef_bit_pos_b >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
	RTLIL::Const result(logic_and(bit_a, bit_b));

	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	RTLIL::Const RTLIL::const_logic_or(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos_a = -1, undef_bit_pos_b = -1;
	BigInteger a = const2big(arg1, signed1, undef_bit_pos_a);
	BigInteger b = const2big(arg2, signed2, undef_bit_pos_b);

	RTLIL::State bit_a = a.isZero() ? undef_bit_pos_a >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
	RTLIL::State bit_b = b.isZero() ? undef_bit_pos_b >= 0 ? RTLIL::State::Sx : RTLIL::State::S0 : RTLIL::State::S1;
	RTLIL::Const result(logic_or(bit_a, bit_b));

	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	static RTLIL::Const const_shift_worker(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool sign_ext, int direction, int result_len)
	{
	int undef_bit_pos = -1;
	BigInteger offset = const2big(arg2, false, undef_bit_pos) * direction;

	if (result_len < 0)
	result_len = arg1.bits.size();

	RTLIL::Const result(RTLIL::State::Sx, result_len);
	if (undef_bit_pos >= 0)
	return result;

	for (int i = 0; i < result_len; i++) {
	BigInteger pos = BigInteger(i) + offset;
	if (pos < 0)
	result.bits[i] = RTLIL::State::S0;
	else if (pos >= BigInteger(int(arg1.bits.size())))
	result.bits[i] = sign_ext ? arg1.bits.back() : RTLIL::State::S0;
	else
	result.bits[i] = arg1.bits[pos.toInt()];
	}

	return result;
	}

	RTLIL::Const RTLIL::const_shl(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
	{
	RTLIL::Const arg1_ext = arg1;
	extend_u0(arg1_ext, result_len, signed1);
	return const_shift_worker(arg1_ext, arg2, false, -1, result_len);
	}

	RTLIL::Const RTLIL::const_shr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool, int result_len)
	{
	RTLIL::Const arg1_ext = arg1;
	extend_u0(arg1_ext, max(result_len, GetSize(arg1)), signed1);
	return const_shift_worker(arg1_ext, arg2, false, +1, result_len);
	}

	RTLIL::Const RTLIL::const_sshl(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	if (!signed1)
	return const_shl(arg1, arg2, signed1, signed2, result_len);
	return const_shift_worker(arg1, arg2, true, -1, result_len);
	}

	RTLIL::Const RTLIL::const_sshr(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	if (!signed1)
	return const_shr(arg1, arg2, signed1, signed2, result_len);
	return const_shift_worker(arg1, arg2, true, +1, result_len);
	}

	static RTLIL::Const const_shift_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool, bool signed2, int result_len, RTLIL::State other_bits)
	{
	int undef_bit_pos = -1;
	BigInteger offset = const2big(arg2, signed2, undef_bit_pos);

	if (result_len < 0)
	result_len = arg1.bits.size();

	RTLIL::Const result(RTLIL::State::Sx, result_len);
	if (undef_bit_pos >= 0)
	return result;

	for (int i = 0; i < result_len; i++) {
	BigInteger pos = BigInteger(i) + offset;
	if (pos < 0 \|\| pos >= BigInteger(int(arg1.bits.size())))
	result.bits[i] = other_bits;
	else
	result.bits[i] = arg1.bits[pos.toInt()];
	}

	return result;
	}

	RTLIL::Const RTLIL::const_shift(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::S0);
	}

	RTLIL::Const RTLIL::const_shiftx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	return const_shift_shiftx(arg1, arg2, signed1, signed2, result_len, RTLIL::State::Sx);
	}

	RTLIL::Const RTLIL::const_lt(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	bool y = const2big(arg1, signed1, undef_bit_pos) < const2big(arg2, signed2, undef_bit_pos);
	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	RTLIL::Const RTLIL::const_le(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	bool y = const2big(arg1, signed1, undef_bit_pos) <= const2big(arg2, signed2, undef_bit_pos);
	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	RTLIL::Const RTLIL::const_eq(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	RTLIL::Const arg1_ext = arg1;
	RTLIL::Const arg2_ext = arg2;
	RTLIL::Const result(RTLIL::State::S0, result_len);

	int width = max(arg1_ext.bits.size(), arg2_ext.bits.size());
	extend_u0(arg1_ext, width, signed1 && signed2);
	extend_u0(arg2_ext, width, signed1 && signed2);

	RTLIL::State matched_status = RTLIL::State::S1;
	for (size_t i = 0; i < arg1_ext.bits.size(); i++) {
	if (arg1_ext.bits.at(i) == RTLIL::State::S0 && arg2_ext.bits.at(i) == RTLIL::State::S1)
	return result;
	if (arg1_ext.bits.at(i) == RTLIL::State::S1 && arg2_ext.bits.at(i) == RTLIL::State::S0)
	return result;
	if (arg1_ext.bits.at(i) > RTLIL::State::S1 \|\| arg2_ext.bits.at(i) > RTLIL::State::S1)
	matched_status = RTLIL::State::Sx;
	}

	result.bits.front() = matched_status;
	return result;
	}

	RTLIL::Const RTLIL::const_ne(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	RTLIL::Const result = RTLIL::const_eq(arg1, arg2, signed1, signed2, result_len);
	if (result.bits.front() == RTLIL::State::S0)
	result.bits.front() = RTLIL::State::S1;
	else if (result.bits.front() == RTLIL::State::S1)
	result.bits.front() = RTLIL::State::S0;
	return result;
	}

	RTLIL::Const RTLIL::const_eqx(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	RTLIL::Const arg1_ext = arg1;
	RTLIL::Const arg2_ext = arg2;
	RTLIL::Const result(RTLIL::State::S0, result_len);

	int width = max(arg1_ext.bits.size(), arg2_ext.bits.size());
	extend_u0(arg1_ext, width, signed1 && signed2);
	extend_u0(arg2_ext, width, signed1 && signed2);

	for (size_t i = 0; i < arg1_ext.bits.size(); i++) {
	if (arg1_ext.bits.at(i) != arg2_ext.bits.at(i))
	return result;
	}

	result.bits.front() = RTLIL::State::S1;
	return result;
	}

	RTLIL::Const RTLIL::const_nex(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	RTLIL::Const result = RTLIL::const_eqx(arg1, arg2, signed1, signed2, result_len);
	if (result.bits.front() == RTLIL::State::S0)
	result.bits.front() = RTLIL::State::S1;
	else if (result.bits.front() == RTLIL::State::S1)
	result.bits.front() = RTLIL::State::S0;
	return result;
	}

	RTLIL::Const RTLIL::const_ge(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	bool y = const2big(arg1, signed1, undef_bit_pos) >= const2big(arg2, signed2, undef_bit_pos);
	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	RTLIL::Const RTLIL::const_gt(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	bool y = const2big(arg1, signed1, undef_bit_pos) > const2big(arg2, signed2, undef_bit_pos);
	RTLIL::Const result(undef_bit_pos >= 0 ? RTLIL::State::Sx : y ? RTLIL::State::S1 : RTLIL::State::S0);

	while (int(result.bits.size()) < result_len)
	result.bits.push_back(RTLIL::State::S0);
	return result;
	}

	RTLIL::Const RTLIL::const_add(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	BigInteger y = const2big(arg1, signed1, undef_bit_pos) + const2big(arg2, signed2, undef_bit_pos);
	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
	}

	RTLIL::Const RTLIL::const_sub(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	BigInteger y = const2big(arg1, signed1, undef_bit_pos) - const2big(arg2, signed2, undef_bit_pos);
	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), undef_bit_pos);
	}

	RTLIL::Const RTLIL::const_mul(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	BigInteger y = const2big(arg1, signed1, undef_bit_pos) * const2big(arg2, signed2, undef_bit_pos);
	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
	}

	RTLIL::Const RTLIL::const_div(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	BigInteger a = const2big(arg1, signed1, undef_bit_pos);
	BigInteger b = const2big(arg2, signed2, undef_bit_pos);
	if (b.isZero())
	return RTLIL::Const(RTLIL::State::Sx, result_len);
	bool result_neg = (a.getSign() == BigInteger::negative) != (b.getSign() == BigInteger::negative);
	a = a.getSign() == BigInteger::negative ? -a : a;
	b = b.getSign() == BigInteger::negative ? -b : b;
	return big2const(result_neg ? -(a / b) : (a / b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
	}

	RTLIL::Const RTLIL::const_mod(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;
	BigInteger a = const2big(arg1, signed1, undef_bit_pos);
	BigInteger b = const2big(arg2, signed2, undef_bit_pos);
	if (b.isZero())
	return RTLIL::Const(RTLIL::State::Sx, result_len);
	bool result_neg = a.getSign() == BigInteger::negative;
	a = a.getSign() == BigInteger::negative ? -a : a;
	b = b.getSign() == BigInteger::negative ? -b : b;
	return big2const(result_neg ? -(a % b) : (a % b), result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
	}

	RTLIL::Const RTLIL::const_pow(const RTLIL::Const &arg1, const RTLIL::Const &arg2, bool signed1, bool signed2, int result_len)
	{
	int undef_bit_pos = -1;

	BigInteger a = const2big(arg1, signed1, undef_bit_pos);
	BigInteger b = const2big(arg2, signed2, undef_bit_pos);
	BigInteger y = 1;

	if (a == 0 && b < 0)
	return RTLIL::Const(RTLIL::State::Sx, result_len);

	if (a == 0 && b > 0)
	return RTLIL::Const(RTLIL::State::S0, result_len);

	if (b < 0)
	{
	if (a < -1 \|\| a > 1)
	y = 0;
	if (a == -1)
	y = (-b % 2) == 0 ? 1 : -1;
	}

	if (b > 0)
	{
	// Power-modulo with 2^result_len as modulus
	BigInteger modulus = 1;
	int modulus_bits = (result_len >= 0 ? result_len : 1024);
	for (int i = 0; i < modulus_bits; i++)
	modulus *= 2;

	bool flip_result_sign = false;
	if (a < 0) {
	a *= -1;
	if (b % 2 == 1)
	flip_result_sign = true;
	}

	while (b > 0) {
	if (b % 2 == 1)
	y = (y * a) % modulus;
	b = b / 2;
	a = (a * a) % modulus;
	}

	if (flip_result_sign)
	y *= -1;
	}

	return big2const(y, result_len >= 0 ? result_len : max(arg1.bits.size(), arg2.bits.size()), min(undef_bit_pos, 0));
	}

	RTLIL::Const RTLIL::const_pos(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
	{
	RTLIL::Const arg1_ext = arg1;
	extend_u0(arg1_ext, result_len, signed1);

	return arg1_ext;
	}

	RTLIL::Const RTLIL::const_neg(const RTLIL::Const &arg1, const RTLIL::Const&, bool signed1, bool, int result_len)
	{
	RTLIL::Const arg1_ext = arg1;
	RTLIL::Const zero(RTLIL::State::S0, 1);

	return RTLIL::const_sub(zero, arg1_ext, true, signed1, result_len);
	}

	YOSYS_NAMESPACE_END