yosys/passes/pmgen/xilinx_dsp.pmg

pattern xilinx_dsp

state <SigBit> clock
state <SigSpec> sigA sigB sigY sigS
state <Cell*> addAB muxAB

match mul
	select mul->type.in($__MUL25X18)
endmatch

match ffA
	select ffA->type.in($dff) /* TODO: $dffe */
	// select nusers(port(ffA, \Q)) == 2
	index <SigSpec> port(ffA, \Q) === port(mul, \A)
	// DSP48E1 does not support clock inversion
	index <SigBit> port(ffA, \CLK_POLARITY) === State::S1
	optional
endmatch

code sigA clock
	sigA = port(mul, \A);

	if (ffA) {
		sigA = port(ffA, \D);
		clock = port(ffA, \CLK).as_bit();
	}
endcode

match ffB
	select ffB->type.in($dff)
	// select nusers(port(ffB, \Q)) == 2
	index <SigSpec> port(ffB, \Q) === port(mul, \B)
	index <SigBit> port(ffB, \CLK_POLARITY) === State::S1
	optional
endmatch

code sigB clock 
	sigB = port(mul, \B);

	if (ffB) {
		sigB = port(ffB, \D);
		SigBit c = port(ffB, \CLK).as_bit();

		if (clock != SigBit() && c != clock)
			reject;

		clock = c;
	}
endcode

match ffY
	select ffY->type.in($dff)
	select nusers(port(ffY, \D)) == 2
	index <SigSpec> port(ffY, \D) === port(mul, \Y)
	index <SigBit> port(ffY, \CLK_POLARITY) === State::S1
	optional
endmatch

code sigY clock
	sigY = port(mul, \Y);

	if (ffY) {
		sigY = port(ffY, \Q);
		SigBit c = port(ffY, \CLK).as_bit();

		if (clock != SigBit() && c != clock)
			reject;

		clock = c;
	}
endcode