yosys/passes/pmgen/xilinx_dsp.pmg

106 lines
2.5 KiB
Plaintext

pattern xilinx_dsp
state <SigBit> clock
state <SigSpec> sigPused
match dsp
select dsp->type.in(\DSP48E1)
endmatch
match ffA
select ffA->type.in($dff)
// DSP48E1 does not support clock inversion
select param(ffA, \CLK_POLARITY).as_bool()
filter param(dsp, \AREG).as_int() == 0
filter !port(dsp, \A).remove_const().empty()
filter includes(port(ffA, \Q).to_sigbit_set(), port(dsp, \A).remove_const().to_sigbit_set())
optional
endmatch
code clock
if (ffA)
clock = port(ffA, \CLK).as_bit();
endcode
match ffB
select ffB->type.in($dff)
// DSP48E1 does not support clock inversion
select param(ffB, \CLK_POLARITY).as_bool()
filter param(dsp, \BREG).as_int() == 0
filter !port(dsp, \B).remove_const().empty()
filter includes(port(ffB, \Q).to_sigbit_set(), port(dsp, \B).remove_const().to_sigbit_set())
optional
endmatch
code clock
if (ffB) {
SigBit c = port(ffB, \CLK).as_bit();
if (clock != SigBit() && c != clock)
reject;
clock = c;
}
endcode
// Extract the bits of P that actually have a consumer
// (as opposed to being a sign extension)
code sigPused
SigSpec P = port(dsp, \P);
int i;
for (i = GetSize(P); i > 0; i--)
if (nusers(P[i-1]) > 1)
break;
sigPused = P.extract(0, i).remove_const();
endcode
match ffP
if !sigPused.empty()
select ffP->type.in($dff)
select nusers(port(ffP, \D)) == 2
// DSP48E1 does not support clock inversion
select param(ffP, \CLK_POLARITY).as_bool()
filter param(dsp, \PREG).as_int() == 0
filter param(ffP, \WIDTH).as_int() >= GetSize(sigPused)
filter includes(port(ffP, \D).to_sigbit_set(), sigPused.to_sigbit_set())
optional
endmatch
// $mux cell left behind by dff2dffe
// would prefer not to run 'opt_expr -mux_undef'
// since that would lose information helpful for
// efficient wide-mux inference
match muxP
if !sigPused.empty() && !ffP
select muxP->type.in($mux)
select nusers(port(muxP, \B)) == 2
select port(muxP, \A).is_fully_undef()
filter param(muxP, \WIDTH).as_int() >= GetSize(sigPused)
filter includes(port(muxP, \B).to_sigbit_set(), sigPused.to_sigbit_set())
optional
endmatch
match ffY
if muxP
select ffY->type.in($dff, $dffe)
select nusers(port(ffY, \D)) == 2
// DSP48E1 does not support clock inversion
select param(ffY, \CLK_POLARITY).as_bool()
filter param(ffY, \WIDTH).as_int() >= GetSize(sigPused)
filter includes(port(ffY, \D).to_sigbit_set(), port(muxP, \Y).to_sigbit_set())
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