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Continued work on counter extraction. Can recognize compatible RTL counters but not replace with hard macros.

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This commit is contained in:
Andrew Zonenberg 2016-03-30 21:54:23 -07:00
parent d16d05e415
commit ad19e0c64a
1 changed files with 161 additions and 107 deletions
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268
passes/techmap/counters.cc
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@ -25,9 +25,9 @@ USING_YOSYS_NAMESPACE
PRIVATE_NAMESPACE_BEGIN PRIVATE_NAMESPACE_BEGIN
//get the list of cells hooked up to at least one bit of a given net //get the list of cells hooked up to at least one bit of a given net
std::set<Cell*> get_other_cells(const RTLIL::SigSpec& port, ModIndex& index, Cell* src) pool<Cell*> get_other_cells(const RTLIL::SigSpec& port, ModIndex& index, Cell* src)
{ {
std::set<Cell*> rval; pool<Cell*> rval;
for(auto b : port) for(auto b : port)
{ {
pool<ModIndex::PortInfo> ports = index.query_ports(b); pool<ModIndex::PortInfo> ports = index.query_ports(b);
@ -41,8 +41,16 @@ std::set<Cell*> get_other_cells(const RTLIL::SigSpec& port, ModIndex& index, Cel
return rval; return rval;
} }
//return true if there is a full-width bus connection between the two named module/port combos //return true if there is a full-width bus connection from cell a port ap to cell b port bp
bool is_full_bus(const RTLIL::SigSpec& sig, ModIndex& index, Cell* a, RTLIL::IdString ap, Cell* b, RTLIL::IdString bp) //if other_conns_allowed is false, then we require a strict point to point connection (no other links)
bool is_full_bus(
const RTLIL::SigSpec& sig,
ModIndex& index,
Cell* a,
RTLIL::IdString ap,
Cell* b,
RTLIL::IdString bp,
bool other_conns_allowed = false)
{ {
for(auto s : sig) for(auto s : sig)
{ {
@ -55,7 +63,7 @@ bool is_full_bus(const RTLIL::SigSpec& sig, ModIndex& index, Cell* a, RTLIL::IdS
found_a = true; found_a = true;
else if( (x.cell == b) && (x.port == bp) ) else if( (x.cell == b) && (x.port == bp) )
found_b = true; found_b = true;
else else if(!other_conns_allowed)
return false; return false;
} }
@ -79,108 +87,149 @@ bool is_unconnected(const RTLIL::SigSpec& port, ModIndex& index)
return true; return true;
} }
void counters_worker(SigMap &sigmap, Module *module, Cell *cell) void counters_worker(ModIndex& index, Module */*module*/, Cell *cell, unsigned int& total_counters)
{ {
if (cell->type == "$alu") SigMap& sigmap = index.sigmap;
{
//GreenPak does not support counters larger than 14 bits so immediately skip anything bigger //Core of the counter must be an ALU
int a_width = cell->getParam("\\A_WIDTH").as_int(); if (cell->type != "$alu")
if(a_width > 14)
return;
//Second input must be a single bit
int b_width = cell->getParam("\\B_WIDTH").as_int();
if(b_width != 1)
return;
//Both inputs must be unsigned, so don't extract anything with a signed input
bool a_sign = cell->getParam("\\A_SIGNED").as_bool();
bool b_sign = cell->getParam("\\B_SIGNED").as_bool();
if(a_sign || b_sign)
return;
//To be a counter, one input of the ALU must be a constant 1
//TODO: can A or B be swapped in synthesized RTL or is B always the 1?
const RTLIL::SigSpec b_port = sigmap(cell->getPort("\\B"));
if(!b_port.is_fully_const() || (b_port.as_int() != 1) )
return;
//BI and CI must be constant 1 as well
const RTLIL::SigSpec bi_port = sigmap(cell->getPort("\\BI"));
if(!bi_port.is_fully_const() || (bi_port.as_int() != 1) )
return;
const RTLIL::SigSpec ci_port = sigmap(cell->getPort("\\CI"));
if(!ci_port.is_fully_const() || (ci_port.as_int() != 1) )
return;
//Index the module
ModIndex index(module);
//We found a decrementer. Not sure if it's a counter yet but log for debugging
log(" Found candidate counter %s (width %d)\n", cell->name.c_str(), a_width);
//CO and X must be unconnected (exactly one connection to each port)
if(!is_unconnected(sigmap(cell->getPort("\\CO")), index))
return;
if(!is_unconnected(sigmap(cell->getPort("\\X")), index))
return;
//Y must have exactly one connection, and it has to be a $mux cell.
//We must have a direct bus connection from our Y to their A.
const RTLIL::SigSpec aluy = sigmap(cell->getPort("\\Y"));
std::set<Cell*> y_loads = get_other_cells(aluy, index, cell);
if(y_loads.size() != 1)
return;
Cell* count_mux = *y_loads.begin();
if(count_mux->type != "$mux")
return;
if(!is_full_bus(aluy, index, cell, "\\Y", count_mux, "\\A"))
return;
//B connection of the mux is our overflow value
const RTLIL::SigSpec overflow = sigmap(count_mux->getPort("\\B"));
if(!overflow.is_fully_const())
return;
int count_value = overflow.as_int();
//TODO: S connection of the mux must come from an inverter
//Y connection of the mux must have exactly one load, the counter's internal register
const RTLIL::SigSpec muxy = sigmap(count_mux->getPort("\\Y"));
std::set<Cell*> muxy_loads = get_other_cells(muxy, index, count_mux);
if(muxy_loads.size() != 1)
return;
Cell* count_reg = *muxy_loads.begin();
if(count_reg->type != "$dff") //TODO: support dffr/dffs?
return;
if(!is_full_bus(muxy, index, count_mux, "\\Y", count_reg, "\\D"))
return;
log(" Looks like a counter so far (count value = %d, count_reg = %s)\n",
count_value, count_reg->name.c_str());
/*
log("Converting %s cell %s.%s to $adff.\n", log_id(cell->type), log_id(module), log_id(cell));
if (GetSize(setctrl) == 1) {
cell->setPort("\\ARST", setctrl);
cell->setParam("\\ARST_POLARITY", setpol);
} else {
cell->setPort("\\ARST", clrctrl);
cell->setParam("\\ARST_POLARITY", clrpol);
}
cell->type = "$adff";
cell->unsetPort("\\SET");
cell->unsetPort("\\CLR");
cell->setParam("\\ARST_VALUE", reset_val);
cell->unsetParam("\\SET_POLARITY");
cell->unsetParam("\\CLR_POLARITY");
return; return;
*/
//GreenPak does not support counters larger than 14 bits so immediately skip anything bigger
int a_width = cell->getParam("\\A_WIDTH").as_int();
if(a_width > 14)
return;
//Second input must be a single bit
int b_width = cell->getParam("\\B_WIDTH").as_int();
if(b_width != 1)
return;
//Both inputs must be unsigned, so don't extract anything with a signed input
bool a_sign = cell->getParam("\\A_SIGNED").as_bool();
bool b_sign = cell->getParam("\\B_SIGNED").as_bool();
if(a_sign || b_sign)
return;
//To be a counter, one input of the ALU must be a constant 1
//TODO: can A or B be swapped in synthesized RTL or is B always the 1?
const RTLIL::SigSpec b_port = sigmap(cell->getPort("\\B"));
if(!b_port.is_fully_const() || (b_port.as_int() != 1) )
return;
//BI and CI must be constant 1 as well
const RTLIL::SigSpec bi_port = sigmap(cell->getPort("\\BI"));
if(!bi_port.is_fully_const() || (bi_port.as_int() != 1) )
return;
const RTLIL::SigSpec ci_port = sigmap(cell->getPort("\\CI"));
if(!ci_port.is_fully_const() || (ci_port.as_int() != 1) )
return;
//CO and X must be unconnected (exactly one connection to each port)
if(!is_unconnected(sigmap(cell->getPort("\\CO")), index))
return;
if(!is_unconnected(sigmap(cell->getPort("\\X")), index))
return;
//Y must have exactly one connection, and it has to be a $mux cell.
//We must have a direct bus connection from our Y to their A.
const RTLIL::SigSpec aluy = sigmap(cell->getPort("\\Y"));
pool<Cell*> y_loads = get_other_cells(aluy, index, cell);
if(y_loads.size() != 1)
return;
Cell* count_mux = *y_loads.begin();
if(count_mux->type != "$mux")
return;
if(!is_full_bus(aluy, index, cell, "\\Y", count_mux, "\\A"))
return;
//B connection of the mux is our overflow value
const RTLIL::SigSpec overflow = sigmap(count_mux->getPort("\\B"));
if(!overflow.is_fully_const())
return;
int count_value = overflow.as_int();
//S connection of the mux must come from an inverter (need not be the only load)
const RTLIL::SigSpec muxsel = sigmap(count_mux->getPort("\\S"));
pool<Cell*> muxsel_conns = get_other_cells(muxsel, index, count_mux);
Cell* underflow_inv = NULL;
for(auto c : muxsel_conns)
{
if(c->type != "$logic_not")
continue;
if(!is_full_bus(muxsel, index, c, "\\Y", count_mux, "\\S", true))
continue;
underflow_inv = c;
break;
} }
if(underflow_inv == NULL)
return;
//Y connection of the mux must have exactly one load, the counter's internal register
const RTLIL::SigSpec muxy = sigmap(count_mux->getPort("\\Y"));
pool<Cell*> muxy_loads = get_other_cells(muxy, index, count_mux);
if(muxy_loads.size() != 1)
return;
Cell* count_reg = *muxy_loads.begin();
if(count_reg->type != "$dff") //TODO: support dffr/dffs?
return;
if(!is_full_bus(muxy, index, count_mux, "\\Y", count_reg, "\\D"))
return;
//Register output must have exactly two loads, the inverter and ALU
const RTLIL::SigSpec cnout = sigmap(count_reg->getPort("\\Q"));
pool<Cell*> cnout_loads = get_other_cells(cnout, index, count_reg);
if(cnout_loads.size() != 2)
return;
if(!is_full_bus(cnout, index, count_reg, "\\Q", underflow_inv, "\\A", true))
return;
if(!is_full_bus(cnout, index, count_reg, "\\Q", cell, "\\A", true))
return;
//Register output net must have an INIT attribute equal to the count value
auto rwire = cnout.as_wire();
if(rwire->attributes.find("\\init") == rwire->attributes.end())
return;
int rinit = rwire->attributes["\\init"].as_int();
if(rinit != count_value)
return;
//Figure out the final cell type based on the counter size
string celltype = "\\GP_COUNT8";
if(a_width > 8)
celltype = "\\GP_COUNT14";
//Log it
total_counters ++;
log(" Extracting %d-bit counter to %s hard macro\n", a_width, celltype.c_str());
log(" Decrementer: %s\n", cell->name.c_str());
log(" Output mux: %s\n", count_mux->name.c_str());
log(" Register: %s\n", count_reg->name.c_str());
log(" Comparator: %s\n", underflow_inv->name.c_str());
log(" Count value: %d\n", count_value);
/*
log("Converting %s cell %s.%s to $adff.\n", log_id(cell->type), log_id(module), log_id(cell));
if (GetSize(setctrl) == 1) {
cell->setPort("\\ARST", setctrl);
cell->setParam("\\ARST_POLARITY", setpol);
} else {
cell->setPort("\\ARST", clrctrl);
cell->setParam("\\ARST_POLARITY", clrpol);
}
cell->type = "$adff";
cell->unsetPort("\\SET");
cell->unsetPort("\\CLR");
cell->setParam("\\ARST_VALUE", reset_val);
cell->unsetParam("\\SET_POLARITY");
cell->unsetParam("\\CLR_POLARITY");
return;
*/
} }
struct CountersPass : public Pass { struct CountersPass : public Pass {
@ -208,12 +257,17 @@ struct CountersPass : public Pass {
} }
extra_args(args, argidx, design); extra_args(args, argidx, design);
for (auto module : design->selected_modules()) { unsigned int total_counters = 0;
SigMap sigmap(module); for (auto module : design->selected_modules())
{
ModIndex index(module);
for (auto cell : module->selected_cells()) for (auto cell : module->selected_cells())
counters_worker(sigmap, module, cell); counters_worker(index, module, cell, total_counters);
} }
if(total_counters)
log("Extracted %u counters\n", total_counters);
} }
} CountersPass; } CountersPass;