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kernel/ff: Refactor FfData to enable FFs with async load.

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- *_en is split into *_ce (clock enable) and *_aload (async load aka
  latch gate enable), so both can be present at once
- has_d is removed
- has_gclk is added (to have a clear marker for $ff)
- d_is_const and val_d leftovers are removed
- async2sync, clk2fflogic, opt_dff are updated to operate correctly on
  FFs with async load
This commit is contained in:
Marcelina Kościelnicka 2021-10-01 23:50:48 +02:00
parent ec2b5548fe
commit 63b9df8693
10 changed files with 565 additions and 325 deletions
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22
passes/memory/memory_dff.cc
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@ -71,9 +71,9 @@ struct MemQueryCache
// port_ren is an upper bound on when we care about the value fetched
// from memory this cycle.
int ren = ezSAT::CONST_TRUE;
if (ff.has_en) {
ren = qcsat.importSigBit(ff.sig_en);
if (!ff.pol_en)
if (ff.has_ce) {
ren = qcsat.importSigBit(ff.sig_ce);
if (!ff.pol_ce)
ren = qcsat.ez->NOT(ren);
}
if (ff.has_srst) {
@ -347,6 +347,10 @@ struct MemoryDffWorker
log("output latches are not supported.\n");
return;
}
if (ff.has_aload) {
log("output FF has async load, not supported.\n");
return;
}
if (ff.has_sr) {
// Latches and FFs with SR are not supported.
log("output FF has both set and reset, not supported.\n");
@ -491,8 +495,8 @@ struct MemoryDffWorker
log("merging output FF to cell.\n");
merger.remove_output_ff(bits);
if (ff.has_en && !ff.pol_en)
ff.sig_en = module->LogicNot(NEW_ID, ff.sig_en);
if (ff.has_ce && !ff.pol_ce)
ff.sig_ce = module->LogicNot(NEW_ID, ff.sig_ce);
if (ff.has_arst && !ff.pol_arst)
ff.sig_arst = module->LogicNot(NEW_ID, ff.sig_arst);
if (ff.has_srst && !ff.pol_srst)
@ -500,8 +504,8 @@ struct MemoryDffWorker
port.clk = ff.sig_clk;
port.clk_enable = true;
port.clk_polarity = ff.pol_clk;
if (ff.has_en)
port.en = ff.sig_en;
if (ff.has_ce)
port.en = ff.sig_ce;
else
port.en = State::S1;
if (ff.has_arst) {
@ -551,6 +555,10 @@ struct MemoryDffWorker
log("address latches are not supported.\n");
return;
}
if (ff.has_aload) {
log("address FF has async load, not supported.\n");
return;
}
if (ff.has_sr || ff.has_arst) {
log("address FF has async set and/or reset, not supported.\n");
return;