yosys/passes/pmgen/xilinx_dsp.pmg

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pattern xilinx_dsp
state <SigBit> clock
state <int> P_WIDTH
match dsp
select dsp->type.in(\DSP48E1)
endmatch
match ffA
select ffA->type.in($dff, $dffe)
select param(ffA, \CLK_POLARITY).as_bool()
// select nusers(port(ffA, \Q)) == 2
index <SigSpec> port(ffA, \Q).extend_u0(25, true) === port(dsp, \A).extract(0, 25)
// DSP48E1 does not support clock inversion
optional
endmatch
code clock
if (ffA)
clock = port(ffA, \CLK).as_bit();
endcode
match ffB
select ffB->type.in($dff, $dffe)
select param(ffB, \CLK_POLARITY).as_bool()
// select nusers(port(ffB, \Q)) == 2
index <SigSpec> port(ffB, \Q).extend_u0(18, true) === port(dsp, \B)
optional
endmatch
code clock
if (ffB) {
SigBit c = port(ffB, \CLK).as_bit();
if (clock != SigBit() && c != clock)
reject;
clock = c;
}
endcode
code P_WIDTH
SigSpec P = port(dsp, \P);
int i;
for (i = GetSize(P); i > 0; i--)
if (nusers(P[i-1]) > 1)
break;
P_WIDTH = i;
endcode
match ffP
select ffP->type.in($dff, $dffe)
select nusers(port(ffP, \D)) == 2
filter param(ffP, \WIDTH).as_int() == P_WIDTH
filter port(ffP, \D) == port(dsp, \P).extract(0, P_WIDTH)
index <Const> param(ffP, \CLK_POLARITY) === State::S1
optional
endmatch
// $mux cell left behind by dff2dffe
// would prefer not to run 'opt_expr -mux_undef'
// since that would lose information helpful for
// efficient wide-mux inference
match muxP
if !ffP
select muxP->type.in($mux)
select port(muxP, \A).is_fully_undef()
filter param(muxP, \WIDTH).as_int() == P_WIDTH
filter port(muxP, \B) == port(dsp, \P).extract(0, P_WIDTH)
select nusers(port(muxP, \B)) == 2
optional
endmatch
match ffY
if muxP
select ffY->type.in($dff, $dffe)
select nusers(port(ffY, \D)) == 2
index <SigSpec> port(ffY, \D) === port(muxP, \Y)
endmatch
code ffP clock
if (ffY)
ffP = ffY;
if (ffP) {
SigBit c = port(ffP, \CLK).as_bit();
if (clock != SigBit() && c != clock)
reject;
clock = c;
}
endcode