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Diffstat (limited to 'ice40/pack.cc')
-rw-r--r-- | ice40/pack.cc | 122 |
1 files changed, 122 insertions, 0 deletions
diff --git a/ice40/pack.cc b/ice40/pack.cc new file mode 100644 index 00000000..ff421c17 --- /dev/null +++ b/ice40/pack.cc @@ -0,0 +1,122 @@ +/* + * nextpnr -- Next Generation Place and Route + * + * Copyright (C) 2018 Clifford Wolf <clifford@clifford.at> + * Copyright (C) 2018 David Shah <dave@ds0.me> + * + * Permission to use, copy, modify, and/or distribute this software for any + * purpose with or without fee is hereby granted, provided that the above + * copyright notice and this permission notice appear in all copies. + * + * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES + * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF + * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR + * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES + * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN + * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF + * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. + * + */ + +#include "pack.h" +#include "cells.h" +#include "design_utils.h" +#include "log.h" + +#include <unordered_set> + +// Pack LUTs and LUT-FF pairs +static void pack_lut_lutffs(Design *design) +{ + std::unordered_set<IdString> packed_cells; + std::vector<CellInfo *> new_cells; + for (auto cell : design->cells) { + CellInfo *ci = cell.second; + log_info("cell '%s' is of type '%s'\n", ci->name.c_str(), + ci->type.c_str()); + if (is_lut(ci)) { + CellInfo *packed = create_ice_cell(design, "ICESTORM_LC", + std::string(ci->name) + "_LC"); + packed_cells.insert(ci->name); + new_cells.push_back(packed); + log_info("packed cell %s into %s\n", ci->name.c_str(), + packed->name.c_str()); + // See if we can pack into a DFF + // TODO: LUT cascade + NetInfo *o = ci->ports.at("O").net; + CellInfo *dff = net_only_drives(o, is_ff, "D", true); + if (dff) { + lut_to_lc(ci, packed, false); + dff_to_lc(dff, packed, false); + design->nets.erase(o->name); + packed_cells.insert(dff->name); + log_info("packed cell %s into %s\n", dff->name.c_str(), + packed->name.c_str()); + } else { + lut_to_lc(ci, packed, true); + } + } + } + for (auto pcell : packed_cells) { + design->cells.erase(pcell); + } + for (auto ncell : new_cells) { + design->cells[ncell->name] = ncell; + } +} + +// Pack FFs not packed as LUTFFs +static void pack_nonlut_ffs(Design *design) +{ + std::unordered_set<IdString> packed_cells; + std::vector<CellInfo *> new_cells; + + for (auto cell : design->cells) { + CellInfo *ci = cell.second; + if (is_ff(ci)) { + CellInfo *packed = create_ice_cell(design, "ICESTORM_LC", + std::string(ci->name) + "_LC"); + packed_cells.insert(ci->name); + new_cells.push_back(packed); + dff_to_lc(ci, packed, true); + } + } + for (auto pcell : packed_cells) { + design->cells.erase(pcell); + } + for (auto ncell : new_cells) { + design->cells[ncell->name] = ncell; + } +} + +// Pack constants (simple implementation) +static void pack_constants(Design *design) +{ + CellInfo *gnd_cell = create_ice_cell(design, "ICESTORM_LC", "$PACKER_GND"); + gnd_cell->attrs["LUT_INIT"] = "0"; + + CellInfo *vcc_cell = create_ice_cell(design, "ICESTORM_LC", "$PACKER_VCC"); + vcc_cell->attrs["LUT_INIT"] = "1"; + + for (auto net : design->nets) { + NetInfo *ni = net.second; + if (ni->driver.cell != nullptr && ni->driver.cell->type == "GND") { + ni->driver.cell = gnd_cell; + ni->driver.port = "O"; + design->cells[gnd_cell->name] = gnd_cell; + } else if (ni->driver.cell != nullptr && + ni->driver.cell->type == "VCC") { + ni->driver.cell = vcc_cell; + ni->driver.port = "O"; + design->cells[vcc_cell->name] = vcc_cell; + } + } +} + +// Main pack function +void pack_design(Design *design) +{ + pack_constants(design); + pack_lut_lutffs(design); + pack_nonlut_ffs(design); +} |