From 6041f780c31525c1fc4d34b95317d7946466957b Mon Sep 17 00:00:00 2001 From: Clifford Wolf Date: Tue, 5 Apr 2016 12:51:04 +0200 Subject: [PATCH] Prefer noninverting FFs in dfflibmap --- passes/techmap/dfflibmap.cc | 24 ++++++++++++++++++++---- 1 file changed, 20 insertions(+), 4 deletions(-) diff --git a/passes/techmap/dfflibmap.cc b/passes/techmap/dfflibmap.cc index 4d7a1a704..3195e5a78 100644 --- a/passes/techmap/dfflibmap.cc +++ b/passes/techmap/dfflibmap.cc @@ -108,6 +108,7 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool LibertyAst *best_cell = NULL; std::map best_cell_ports; int best_cell_pins = 0; + bool best_cell_noninv = false; double best_cell_area = 0; if (ast->id != "library") @@ -155,6 +156,7 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool int num_pins = 0; bool found_output = false; + bool found_noninv_output = false; for (auto pin : cell->children) { if (pin->id != "pin" || pin->args.size() != 1) @@ -175,10 +177,14 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool value.erase(pos, 1); if (value == ff->args[0]) { this_cell_ports[pin->args[0]] = cell_next_pol ? 'Q' : 'q'; + if (cell_next_pol) + found_noninv_output = true; found_output = true; } else if (value == ff->args[1]) { this_cell_ports[pin->args[0]] = cell_next_pol ? 'q' : 'Q'; + if (!cell_next_pol) + found_noninv_output = true; found_output = true; } } @@ -187,7 +193,7 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool this_cell_ports[pin->args[0]] = 0; } - if (!found_output || (best_cell != NULL && num_pins > best_cell_pins)) + if (!found_output || (best_cell != NULL && (num_pins > best_cell_pins || (best_cell_noninv && !found_noninv_output)))) continue; if (best_cell != NULL && num_pins == best_cell_pins && area > best_cell_area) @@ -196,12 +202,14 @@ static void find_cell(LibertyAst *ast, std::string cell_type, bool clkpol, bool best_cell = cell; best_cell_pins = num_pins; best_cell_area = area; + best_cell_noninv = found_noninv_output; best_cell_ports.swap(this_cell_ports); continue_cell_loop:; } if (best_cell != NULL) { - log(" cell %s (pins=%d, area=%.2f) is a direct match for cell type %s.\n", best_cell->args[0].c_str(), best_cell_pins, best_cell_area, cell_type.c_str()); + log(" cell %s (%sinv, pins=%d, area=%.2f) is a direct match for cell type %s.\n", + best_cell->args[0].c_str(), best_cell_noninv ? "non" : "", best_cell_pins, best_cell_area, cell_type.c_str()); if (prepare_mode) { cell_mappings[cell_type].cell_name = cell_type; cell_mappings[cell_type].ports["C"] = 'C'; @@ -221,6 +229,7 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo LibertyAst *best_cell = NULL; std::map best_cell_ports; int best_cell_pins = 0; + bool best_cell_noninv = false; double best_cell_area = 0; if (ast->id != "library") @@ -260,6 +269,7 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo int num_pins = 0; bool found_output = false; + bool found_noninv_output = false; for (auto pin : cell->children) { if (pin->id != "pin" || pin->args.size() != 1) @@ -280,10 +290,14 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo value.erase(pos, 1); if (value == ff->args[0]) { this_cell_ports[pin->args[0]] = cell_next_pol ? 'Q' : 'q'; + if (cell_next_pol) + found_noninv_output = true; found_output = true; } else if (value == ff->args[1]) { this_cell_ports[pin->args[0]] = cell_next_pol ? 'q' : 'Q'; + if (!cell_next_pol) + found_noninv_output = true; found_output = true; } } @@ -292,7 +306,7 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo this_cell_ports[pin->args[0]] = 0; } - if (!found_output || (best_cell != NULL && num_pins > best_cell_pins)) + if (!found_output || (best_cell != NULL && (num_pins > best_cell_pins || (best_cell_noninv && !found_noninv_output)))) continue; if (best_cell != NULL && num_pins == best_cell_pins && area > best_cell_area) @@ -301,12 +315,14 @@ static void find_cell_sr(LibertyAst *ast, std::string cell_type, bool clkpol, bo best_cell = cell; best_cell_pins = num_pins; best_cell_area = area; + best_cell_noninv = found_noninv_output; best_cell_ports.swap(this_cell_ports); continue_cell_loop:; } if (best_cell != NULL) { - log(" cell %s (pins=%d, area=%.2f) is a direct match for cell type %s.\n", best_cell->args[0].c_str(), best_cell_pins, best_cell_area, cell_type.c_str()); + log(" cell %s (%sinv, pins=%d, area=%.2f) is a direct match for cell type %s.\n", + best_cell->args[0].c_str(), best_cell_noninv ? "non" : "", best_cell_pins, best_cell_area, cell_type.c_str()); if (prepare_mode) { cell_mappings[cell_type].cell_name = cell_type; cell_mappings[cell_type].ports["C"] = 'C'; -- 2.30.2