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Merge clock inverters in memory_dff

This commit is contained in:
Clifford Wolf 2015-06-09 07:19:04 +02:00
parent c88be7bae5
commit b57cb4a7fe
1 changed files with 37 additions and 16 deletions
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53
passes/memory/memory_dff.cc
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@ -31,7 +31,8 @@ void normalize_sig(RTLIL::Module *module, RTLIL::SigSpec &sig)
sig.replace(conn.first, conn.second); sig.replace(conn.first, conn.second);
} }
bool find_sig_before_dff(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells, RTLIL::SigSpec &sig, RTLIL::SigSpec &clk, bool &clk_polarity, bool after = false) bool find_sig_before_dff(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells, dict<SigBit, SigBit> &invbits,
RTLIL::SigSpec &sig, RTLIL::SigSpec &clk, bool &clk_polarity, bool after = false)
{ {
normalize_sig(module, sig); normalize_sig(module, sig);
@ -42,10 +43,18 @@ bool find_sig_before_dff(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_c
for (auto cell : dff_cells) for (auto cell : dff_cells)
{ {
SigSpec this_clk = cell->getPort("\\CLK");
bool this_clk_polarity = cell->parameters["\\CLK_POLARITY"].as_bool();
if (invbits.count(this_clk)) {
this_clk = invbits.at(this_clk);
this_clk_polarity = !this_clk_polarity;
}
if (clk != RTLIL::SigSpec(RTLIL::State::Sx)) { if (clk != RTLIL::SigSpec(RTLIL::State::Sx)) {
if (cell->getPort("\\CLK") != clk) if (this_clk != clk)
continue; continue;
if (cell->parameters["\\CLK_POLARITY"].as_bool() != clk_polarity) if (this_clk_polarity != clk_polarity)
continue; continue;
} }
@ -57,8 +66,8 @@ bool find_sig_before_dff(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_c
continue; continue;
bit = d; bit = d;
clk = cell->getPort("\\CLK"); clk = this_clk;
clk_polarity = cell->parameters["\\CLK_POLARITY"].as_bool(); clk_polarity = this_clk_polarity;
goto replaced_this_bit; goto replaced_this_bit;
} }
@ -69,7 +78,7 @@ bool find_sig_before_dff(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_c
return true; return true;
} }
void handle_wr_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells, RTLIL::Cell *cell) void handle_wr_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells, dict<SigBit, SigBit> &invbits, RTLIL::Cell *cell)
{ {
log("Checking cell `%s' in module `%s': ", cell->name.c_str(), module->name.c_str()); log("Checking cell `%s' in module `%s': ", cell->name.c_str(), module->name.c_str());
@ -77,19 +86,19 @@ void handle_wr_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells,
bool clk_polarity = 0; bool clk_polarity = 0;
RTLIL::SigSpec sig_addr = cell->getPort("\\ADDR"); RTLIL::SigSpec sig_addr = cell->getPort("\\ADDR");
if (!find_sig_before_dff(module, dff_cells, sig_addr, clk, clk_polarity)) { if (!find_sig_before_dff(module, dff_cells, invbits, sig_addr, clk, clk_polarity)) {
log("no (compatible) $dff for address input found.\n"); log("no (compatible) $dff for address input found.\n");
return; return;
} }
RTLIL::SigSpec sig_data = cell->getPort("\\DATA"); RTLIL::SigSpec sig_data = cell->getPort("\\DATA");
if (!find_sig_before_dff(module, dff_cells, sig_data, clk, clk_polarity)) { if (!find_sig_before_dff(module, dff_cells, invbits, sig_data, clk, clk_polarity)) {
log("no (compatible) $dff for data input found.\n"); log("no (compatible) $dff for data input found.\n");
return; return;
} }
RTLIL::SigSpec sig_en = cell->getPort("\\EN"); RTLIL::SigSpec sig_en = cell->getPort("\\EN");
if (!find_sig_before_dff(module, dff_cells, sig_en, clk, clk_polarity)) { if (!find_sig_before_dff(module, dff_cells, invbits, sig_en, clk, clk_polarity)) {
log("no (compatible) $dff for enable input found.\n"); log("no (compatible) $dff for enable input found.\n");
return; return;
} }
@ -126,7 +135,7 @@ void disconnect_dff(RTLIL::Module *module, RTLIL::SigSpec sig)
} }
} }
void handle_rd_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells, RTLIL::Cell *cell) void handle_rd_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells, dict<SigBit, SigBit> &invbits, RTLIL::Cell *cell)
{ {
log("Checking cell `%s' in module `%s': ", cell->name.c_str(), module->name.c_str()); log("Checking cell `%s' in module `%s': ", cell->name.c_str(), module->name.c_str());
@ -134,7 +143,7 @@ void handle_rd_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells,
RTLIL::SigSpec clk_data = RTLIL::SigSpec(RTLIL::State::Sx); RTLIL::SigSpec clk_data = RTLIL::SigSpec(RTLIL::State::Sx);
RTLIL::SigSpec sig_data = cell->getPort("\\DATA"); RTLIL::SigSpec sig_data = cell->getPort("\\DATA");
if (find_sig_before_dff(module, dff_cells, sig_data, clk_data, clk_polarity, true) && if (find_sig_before_dff(module, dff_cells, invbits, sig_data, clk_data, clk_polarity, true) &&
clk_data != RTLIL::SigSpec(RTLIL::State::Sx)) clk_data != RTLIL::SigSpec(RTLIL::State::Sx))
{ {
disconnect_dff(module, sig_data); disconnect_dff(module, sig_data);
@ -149,7 +158,7 @@ void handle_rd_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells,
RTLIL::SigSpec clk_addr = RTLIL::SigSpec(RTLIL::State::Sx); RTLIL::SigSpec clk_addr = RTLIL::SigSpec(RTLIL::State::Sx);
RTLIL::SigSpec sig_addr = cell->getPort("\\ADDR"); RTLIL::SigSpec sig_addr = cell->getPort("\\ADDR");
if (find_sig_before_dff(module, dff_cells, sig_addr, clk_addr, clk_polarity) && if (find_sig_before_dff(module, dff_cells, invbits, sig_addr, clk_addr, clk_polarity) &&
clk_addr != RTLIL::SigSpec(RTLIL::State::Sx)) clk_addr != RTLIL::SigSpec(RTLIL::State::Sx))
{ {
cell->setPort("\\CLK", clk_addr); cell->setPort("\\CLK", clk_addr);
@ -166,20 +175,32 @@ void handle_rd_cell(RTLIL::Module *module, std::vector<RTLIL::Cell*> &dff_cells,
void handle_module(RTLIL::Module *module, bool flag_wr_only) void handle_module(RTLIL::Module *module, bool flag_wr_only)
{ {
std::vector<RTLIL::Cell*> dff_cells; vector<Cell*> dff_cells;
dict<SigBit, SigBit> invbits;
for (auto cell : module->cells()) for (auto cell : module->cells()) {
if (cell->type == "$dff") if (cell->type == "$dff")
dff_cells.push_back(cell); dff_cells.push_back(cell);
if (cell->type == "$not" || cell->type == "$_NOT_" || (cell->type == "$logic_not" && GetSize(cell->getPort("\\A")) == 1)) {
SigSpec sig_a = cell->getPort("\\A");
SigSpec sig_y = cell->getPort("\\Y");
if (cell->type == "$not")
sig_a.extend_u0(GetSize(sig_y), cell->getParam("\\A_SIGNED").as_bool());
if (cell->type == "$logic_not")
sig_y.extend_u0(1);
for (int i = 0; i < GetSize(sig_y); i++)
invbits[sig_y[i]] = sig_a[i];
}
}
for (auto cell : module->selected_cells()) for (auto cell : module->selected_cells())
if (cell->type == "$memwr" && !cell->parameters["\\CLK_ENABLE"].as_bool()) if (cell->type == "$memwr" && !cell->parameters["\\CLK_ENABLE"].as_bool())
handle_wr_cell(module, dff_cells, cell); handle_wr_cell(module, dff_cells, invbits, cell);
if (!flag_wr_only) if (!flag_wr_only)
for (auto cell : module->selected_cells()) for (auto cell : module->selected_cells())
if (cell->type == "$memrd" && !cell->parameters["\\CLK_ENABLE"].as_bool()) if (cell->type == "$memrd" && !cell->parameters["\\CLK_ENABLE"].as_bool())
handle_rd_cell(module, dff_cells, cell); handle_rd_cell(module, dff_cells, invbits, cell);
} }
struct MemoryDffPass : public Pass { struct MemoryDffPass : public Pass {