diff options
Diffstat (limited to 'ecp5/arch_place.cc')
| -rw-r--r-- | ecp5/arch_place.cc | 74 |
1 files changed, 74 insertions, 0 deletions
diff --git a/ecp5/arch_place.cc b/ecp5/arch_place.cc index ff70bb5a..e5c9b31f 100644 --- a/ecp5/arch_place.cc +++ b/ecp5/arch_place.cc @@ -18,8 +18,10 @@ */ #include "cells.h" +#include "design_utils.h" #include "log.h" #include "nextpnr.h" +#include "timing.h" #include "util.h" NEXTPNR_NAMESPACE_BEGIN @@ -115,4 +117,76 @@ bool Arch::isValidBelForCell(CellInfo *cell, BelId bel) const } } +void Arch::permute_luts() +{ + NetCriticalityMap nc; + get_criticalities(getCtx(), &nc); + + std::unordered_map<PortInfo *, size_t> port_to_user; + for (auto net : sorted(nets)) { + NetInfo *ni = net.second; + for (size_t i = 0; i < ni->users.size(); i++) { + auto &usr = ni->users.at(i); + port_to_user[&(usr.cell->ports.at(usr.port))] = i; + } + } + + auto proc_lut = [&](CellInfo *ci, int lut) { + std::vector<IdString> port_names; + for (int i = 0; i < 4; i++) + port_names.push_back(id(std::string("ABCD").substr(i, 1) + std::to_string(lut))); + + std::vector<std::pair<float, int>> inputs; + std::vector<NetInfo *> orig_nets; + + for (int i = 0; i < 4; i++) { + auto &port = ci->ports.at(port_names.at(i)); + float crit = 0; + if (port.net != nullptr && nc.count(port.net->name)) { + auto &n = nc.at(port.net->name); + size_t usr = port_to_user.at(&port); + if (usr < n.criticality.size()) + crit = n.criticality.at(usr); + } + orig_nets.push_back(port.net); + inputs.emplace_back(crit, i); + } + // Least critical first (A input is slowest) + std::sort(inputs.begin(), inputs.end()); + for (int i = 0; i < 4; i++) { + IdString p = port_names.at(i); + // log_info("%s %s %f\n", p.c_str(ctx), port_names.at(inputs.at(i).second).c_str(ctx), inputs.at(i).first); + disconnect_port(getCtx(), ci, p); + ci->ports.at(p).net = nullptr; + if (orig_nets.at(inputs.at(i).second) != nullptr) { + connect_port(getCtx(), orig_nets.at(inputs.at(i).second), ci, p); + ci->params[id(p.str(this) + "MUX")] = p.str(this); + } else { + ci->params[id(p.str(this) + "MUX")] = "1"; + } + } + // Rewrite function + int old_init = int_or_default(ci->params, id("LUT" + std::to_string(lut) + "_INITVAL"), 0); + int new_init = 0; + for (int i = 0; i < 16; i++) { + int old_index = 0; + for (int k = 0; k < 4; k++) { + if (i & (1 << k)) + old_index |= (1 << inputs.at(k).second); + } + if (old_init & (1 << old_index)) + new_init |= (1 << i); + } + ci->params[id("LUT" + std::to_string(lut) + "_INITVAL")] = std::to_string(new_init); + }; + + for (auto cell : sorted(cells)) { + CellInfo *ci = cell.second; + if (ci->type == id_TRELLIS_SLICE && str_or_default(ci->params, id("MODE"), "LOGIC") == "LOGIC") { + proc_lut(ci, 0); + proc_lut(ci, 1); + } + } +} + NEXTPNR_NAMESPACE_END |