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Cope with undoing #895

This commit is contained in:
Eddie Hung 2019-04-08 15:57:07 -07:00
parent d3930ca79e
commit 93b1621911
1 changed files with 26 additions and 14 deletions
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40
passes/techmap/shregmap.cc
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@ -96,6 +96,7 @@ struct ShregmapTechGreenpak4 : ShregmapTech
struct ShregmapTechXilinx7 : ShregmapTech
{
dict<SigBit, std::tuple<Cell*,int,int>> sigbit_to_shiftx_offset;
dict<SigBit, SigSpec> sigbit_to_eq_input;
const ShregmapOptions &opts;
ShregmapTechXilinx7(const ShregmapOptions &opts) : opts(opts) {}
@ -113,16 +114,17 @@ struct ShregmapTechXilinx7 : ShregmapTech
}
else if (cell->type == "$mux") {
int j = 0;
for (auto bit : cell->getPort("\\A"))
for (auto bit : sigmap(cell->getPort("\\A")))
sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, 0, j++);
j = 0;
for (auto bit : sigmap(cell->getPort("\\B")))
sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, 1, j++);
}
else if (cell->type == "$pmux") {
if (!cell->get_bool_attribute("\\shiftx_compatible")) continue;
int width = cell->getParam("\\WIDTH").as_int();
int j = 0;
for (auto bit : cell->getPort("\\A"))
for (auto bit : sigmap(cell->getPort("\\A")))
sigbit_to_shiftx_offset[bit] = std::make_tuple(cell, 0, j++);
j = cell->getParam("\\S_WIDTH").as_int();
int k = 0;
@ -135,6 +137,15 @@ struct ShregmapTechXilinx7 : ShregmapTech
}
log_assert(j == 0);
}
else if (cell->type == "$eq") {
auto b_wire = cell->getPort("\\B");
// Keep track of $eq cells that compare against the value 1
// in anticipation that they drive the select (S) port of a $pmux
if (b_wire.is_fully_const() && b_wire.as_int() == 1) {
auto y_wire = sigmap(cell->getPort("\\Y").as_bit());
sigbit_to_eq_input[y_wire] = cell->getPort("\\A");
}
}
}
}
@ -239,19 +250,20 @@ struct ShregmapTechXilinx7 : ShregmapTech
shiftx->setPort("\\Y", cell->module->addWire(NEW_ID));
}
else if (shiftx->type == "$pmux") {
// Create a new encoder, out of a $pmux, that takes
// the existing pmux's 'S' input and transforms it
// back into a binary value
int clog2taps = ceil(log2(taps.size()));
RTLIL::SigSpec b_port;
for (int i = shiftx->getParam("\\S_WIDTH").as_int(); i > 0; i--)
b_port.append(RTLIL::Const(i, clog2taps));
l_wire = cell->module->addWire(NEW_ID, clog2taps);
RTLIL::SigSpec s_wire = cell->module->addWire(NEW_ID, shiftx->getParam("\\S_WIDTH").as_int());
cell->module->connect(s_wire.extract(0, shiftx->getParam("\\S_WIDTH").as_int()), shiftx->getPort("\\S"));
cell->module->addPmux(NEW_ID, RTLIL::Const(0, clog2taps), b_port, s_wire, l_wire);
int group = std::get<2>(it->second);
// If the 'A' port is fully undef, then opt_expr -mux_undef
// has not been applied, so find the second-to-last bit of
// the 'S' port (corresponding to $eq cell comparing for 1)
// otherwise use the last bit of 'S'
const auto& s_wire_bits = shiftx->getPort("\\S").bits();
SigBit s1;
if (shiftx->getPort("\\A").is_fully_undef())
s1 = s_wire_bits[s_wire_bits.size() - 2];
else
s1 = s_wire_bits[s_wire_bits.size() - 1];
RTLIL::SigSpec y_wire = shiftx->getPort("\\Y");
l_wire = sigbit_to_eq_input.at(s1);
log_assert(l_wire.size() == ceil(log2(taps.size())));
int group = std::get<2>(it->second);
q_wire = y_wire[group];
y_wire[group] = cell->module->addWire(NEW_ID);
shiftx->setPort("\\Y", y_wire);