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Improve pattern matcher to match subsets of $dffe? cells

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This commit is contained in:
Eddie Hung 2019-07-18 14:08:18 -07:00
parent 79d63479ea
commit 08fe63c61e
2 changed files with 22 additions and 12 deletions
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10
passes/pmgen/xilinx_dsp.cc
View file

@ -39,7 +39,8 @@ void pack_xilinx_dsp(xilinx_dsp_pm &pm)
log("dsp: %s\n", log_id(st.dsp, "--"));
log("ffP: %s\n", log_id(st.ffP, "--"));
log("muxP: %s\n", log_id(st.muxP, "--"));
log("P_WIDTH: %d\n", st.P_WIDTH);
log("P_used: %s\n", log_signal(st.P_used));
log_module(pm.module);
#endif
log("Analysing %s.%s for Xilinx DSP register packing.\n", log_id(pm.module), log_id(st.dsp));
@ -79,8 +80,13 @@ void pack_xilinx_dsp(xilinx_dsp_pm &pm)
}
if (st.ffP) {
SigSpec P = cell->getPort("\\P");
SigSpec D;
if (st.muxP)
D = st.muxP->getPort("\\B");
else
D = st.ffP->getPort("\\D");
SigSpec Q = st.ffP->getPort("\\Q");
P.replace(Q, P.extract(0, GetSize(Q)));
P.replace(D, Q);
cell->setPort("\\P", Q);
cell->setParam("\\PREG", State::S1);
if (st.ffP->type == "$dff")

24
passes/pmgen/xilinx_dsp.pmg
View file

@ -1,7 +1,7 @@
pattern xilinx_dsp
state <SigBit> clock
state <int> P_WIDTH
state <SigSpec> P_used
match dsp
select dsp->type.in(\DSP48E1)
@ -39,22 +39,25 @@ code clock
}
endcode
code P_WIDTH
// Extract the bits of P that actually have a consumer
// (as opposed to being a sign extension)
code P_used
SigSpec P = port(dsp, \P);
int i;
for (i = GetSize(P); i > 0; i--)
if (nusers(P[i-1]) > 1)
break;
P_WIDTH = i;
P_used = P.extract(0, i).remove_const();
endcode
match ffP
if !P_used.empty()
select ffP->type.in($dff, $dffe)
select nusers(port(ffP, \D)) == 2
// DSP48E1 does not support clock inversion
select param(ffP, \CLK_POLARITY).as_bool()
filter param(ffP, \WIDTH).as_int() == P_WIDTH
filter port(ffP, \D) == port(dsp, \P).extract(0, P_WIDTH)
filter param(ffP, \WIDTH).as_int() >= GetSize(P_used)
filter includes(port(ffP, \D).to_sigbit_set(), P_used.to_sigbit_set())
optional
endmatch
@ -63,12 +66,12 @@ endmatch
// since that would lose information helpful for
// efficient wide-mux inference
match muxP
if !ffP
if !P_used.empty() && !ffP
select muxP->type.in($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
select port(muxP, \A).is_fully_undef()
filter param(muxP, \WIDTH).as_int() >= GetSize(P_used)
filter includes(port(muxP, \B).to_sigbit_set(), P_used.to_sigbit_set())
optional
endmatch
@ -78,7 +81,8 @@ match ffY
select nusers(port(ffY, \D)) == 2
// DSP48E1 does not support clock inversion
select param(ffY, \CLK_POLARITY).as_bool()
index <SigSpec> port(ffY, \D) === port(muxP, \Y)
filter param(ffY, \WIDTH).as_int() >= GetSize(P_used)
filter includes(port(ffY, \D).to_sigbit_set(), port(muxP, \Y).to_sigbit_set())
endmatch
code ffP clock