pattern nexus_mac18

match mul
	select mul->type.in($mul)
	select GetSize(port(mul, \A)) <= 18
	select GetSize(port(mul, \B)) <= 18
	select GetSize(port(mul, \Y)) <= 48
endmatch

match add
	select add->type.in($add, $sub)
	select GetSize(port(add, \Y)) <= 48
	choice <IdString> AB {\A, \B}
	index <SigBit> port(add, AB)[0] === port(mul, \Y)[0]
endmatch

code
	if (mul->getParam(\A_SIGNED).as_bool() != mul->getParam(\B_SIGNED).as_bool()) {
		reject;
	}

	{
		SigSpec mul_out = port(mul, \Y);
		IdString add_AB;

		if (GetSize(port(add, \A)) >= GetSize(mul_out) && port(add, \A).extract(0, GetSize(mul_out)) == mul_out) {
			add_AB = \A;
		} else if (GetSize(port(add, \B)) >= GetSize(mul_out) && port(add, \B).extract(0, GetSize(mul_out)) == mul_out) {
			add_AB = \B;
		} else {
			reject;
		}

		Cell *mac = module->addCell(NEW_ID, "$__NX_MAC18X18");
		IdString add_C = (add_AB == \A) ? \B : \A;

		mac->setPort(\A, port(mul, \A));
		mac->setPort(\B, port(mul, \B));
		mac->setPort(\C, port(add, add_C));
		mac->setPort(\Y, port(add, \Y));
		mac->setParam(\A_SIGNED, mul->getParam(\A_SIGNED)); 
		mac->setParam(\SUBTRACT, add->type == $sub ? State::S1 : State::S0);

		autoremove(mul);
		autoremove(add);
	}

	accept;
endcode

pattern nexus_preadd18

match preadd
	select preadd->type.in($add, $sub)
	select GetSize(port(preadd, \Y)) <= 19
endmatch

match mul
	select mul->type.in($mul)
	select GetSize(port(mul, \Y)) <= 48
	choice <IdString> mul_AB {\A, \B}
	index <SigBit> port(mul, mul_AB)[0] === port(preadd, \Y)[0]
endmatch

match pipe_ff
	select pipe_ff->type.in($dff, $dffe, $sdff, $sdffe)
	index <SigBit> port(pipe_ff, \D)[0] === port(mul, \Y)[0]
	optional
endmatch

code
	SigSpec preadd_out = port(preadd, \Y);
	IdString actual_mul_AB;

	if (GetSize(port(mul, \A)) >= GetSize(preadd_out) && port(mul, \A).extract(0, GetSize(preadd_out)) == preadd_out) {
		actual_mul_AB = \A;
	} else if (GetSize(port(mul, \B)) >= GetSize(preadd_out) && port(mul, \B).extract(0, GetSize(preadd_out)) == preadd_out) {
		actual_mul_AB = \B;
	} else {
		reject;
	}

	{
		Cell *mac = module->addCell(NEW_ID, "$__NX_PREADD18X18");

		IdString mul_other = (actual_mul_AB == \A) ? \B : \A;
		IdString sgn_AC = (mul_other == \A) ? \B_SIGNED : \A_SIGNED;
		IdString sgn_B = (mul_other == \A) ? \A_SIGNED : \B_SIGNED;

		SigSpec sig_A = port(preadd, \A);
		SigSpec sig_C = port(preadd, \B);
		SigSpec sig_B = port(mul, mul_other);

		sig_A.extend_u0(18, false);
		sig_C.extend_u0(18, false);
		sig_B.extend_u0(18, false);

		mac->setPort(\A, sig_A.extract(0, 18));
		mac->setPort(\C, sig_C.extract(0, 18));
		mac->setPort(\B, sig_B.extract(0, 18));

		if (pipe_ff) {
			mac->setPort(\Y, port(pipe_ff, \Q));
			mac->setPort(\CLK, port(pipe_ff, \CLK));
			mac->setParam(\PIPELINED, State::S1);
		} else {
			mac->setPort(\Y, port(mul, \Y));
			mac->setPort(\CLK, State::S0);
			mac->setParam(\PIPELINED, State::S0);
		}

		mac->setParam(\A_SIGNED, mul->getParam(sgn_AC));
		mac->setParam(\B_SIGNED, mul->getParam(sgn_B));
		mac->setParam(\C_SIGNED, mul->getParam(sgn_AC));

		if (pipe_ff) autoremove(pipe_ff);
		autoremove(mul);
		autoremove(preadd);
	}

	accept;
endcode

pattern nexus_mac9_4lane

match add_top
	select add_top->type == $add
endmatch

match add_mid
	select add_mid->type == $add
	index <SigBit> port(add_mid, \Y)[0] === port(add_top, \A)[0]
endmatch

match add_bot
	select add_bot->type == $add
	index <SigBit> port(add_bot, \Y)[0] === port(add_mid, \A)[0]
endmatch

match mul3
	select mul3->type == $mul
	select GetSize(port(mul3, \A)) <= 9 && GetSize(port(mul3, \B)) <= 9
	index <SigBit> port(mul3, \Y)[0] === port(add_top, \B)[0]
endmatch

match mul2
	select mul2->type == $mul
	select GetSize(port(mul2, \A)) <= 9 && GetSize(port(mul2, \B)) <= 9
	index <SigBit> port(mul2, \Y)[0] === port(add_mid, \B)[0]
endmatch

match mul1
	select mul1->type == $mul
	select GetSize(port(mul1, \A)) <= 9 && GetSize(port(mul1, \B)) <= 9
	index <SigBit> port(mul1, \Y)[0] === port(add_bot, \B)[0]
endmatch

match mul0
	select mul0->type == $mul
	select GetSize(port(mul0, \A)) <= 9 && GetSize(port(mul0, \B)) <= 9
	index <SigBit> port(mul0, \Y)[0] === port(add_bot, \A)[0]
endmatch

code
	bool is_signed = mul0->getParam(\A_SIGNED).as_bool();

	if (
		mul0->getParam(\B_SIGNED).as_bool() != is_signed ||
		mul1->getParam(\A_SIGNED).as_bool() != is_signed ||
		mul1->getParam(\B_SIGNED).as_bool() != is_signed ||
		mul2->getParam(\A_SIGNED).as_bool() != is_signed ||
		mul2->getParam(\B_SIGNED).as_bool() != is_signed ||
		mul3->getParam(\A_SIGNED).as_bool() != is_signed ||
		mul3->getParam(\B_SIGNED).as_bool() != is_signed
	) {
		reject;
	}

	{
		Cell *mac = module->addCell(NEW_ID, "$__NX_MAC9X9WIDE_4LANE");
		
		auto ext9 = [&](SigSpec s) { 
			s.extend_u0(9, is_signed); 
			return s;
		};

		mac->setPort(\A0, ext9(port(mul0, \A)));
		mac->setPort(\B0, ext9(port(mul0, \B)));
		mac->setPort(\A1, ext9(port(mul1, \A)));
		mac->setPort(\B1, ext9(port(mul1, \B)));
		mac->setPort(\A2, ext9(port(mul2, \A)));
		mac->setPort(\B2, ext9(port(mul2, \B)));
		mac->setPort(\A3, ext9(port(mul3, \A)));
		mac->setPort(\B3, ext9(port(mul3, \B)));
		mac->setPort(\Y, port(add_top, \Y));
		mac->setParam(\SIGNED, is_signed ? State::S1 : State::S0);

		autoremove(add_top);
		autoremove(add_mid);
		autoremove(add_bot);
		autoremove(mul0);
		autoremove(mul1);
		autoremove(mul2);
		autoremove(mul3);
	}

	accept;
endcode