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Disable memory_dff for initialized FFs 

Signed-off-by: Clifford Wolf <clifford@clifford.at>
This commit is contained in:
Clifford Wolf 2018-05-28 17:16:15 +02:00
parent 74efafc1cf
commit cee4b1e6bc
1 changed files with 19 additions and 1 deletions
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20
passes/memory/memory_dff.cc
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@ -33,8 +33,20 @@ struct MemoryDffWorker
dict<SigBit, int> sigbit_users_count;
dict<SigSpec, Cell*> mux_cells_a, mux_cells_b;
pool<Cell*> forward_merged_dffs, candidate_dffs;
pool<SigBit> init_bits;
MemoryDffWorker(Module *module) : module(module), sigmap(module) { }
MemoryDffWorker(Module *module) : module(module), sigmap(module)
{
for (auto wire : module->wires()) {
if (wire->attributes.count("\\init") == 0)
continue;
SigSpec sig = sigmap(wire);
Const initval = wire->attributes.count("\\init");
for (int i = 0; i < GetSize(sig) && i < GetSize(initval); i++)
if (initval[i] == State::S0 || initval[i] == State::S1)
init_bits.insert(sig[i]);
}
}
bool find_sig_before_dff(RTLIL::SigSpec &sig, RTLIL::SigSpec &clk, bool &clk_polarity, bool after = false)
{
@ -45,6 +57,9 @@ struct MemoryDffWorker
if (bit.wire == NULL)
continue;
if (!after && init_bits.count(sigmap(bit)))
return false;
for (auto cell : dff_cells)
{
if (after && forward_merged_dffs.count(cell))
@ -72,6 +87,9 @@ struct MemoryDffWorker
if (d.size() != 1)
continue;
if (after && init_bits.count(d))
return false;
bit = d;
clk = this_clk;
clk_polarity = this_clk_polarity;