From a3419319727ac1c2012602a702b62631570d7588 Mon Sep 17 00:00:00 2001 From: Clifford Wolf Date: Fri, 18 Jul 2014 14:32:40 +0200 Subject: Only create collision detect logic in memory_share if necessary --- passes/memory/memory_share.cc | 51 +++++++++++++++++++++++++++++++++++++++---- 1 file changed, 47 insertions(+), 4 deletions(-) (limited to 'passes') diff --git a/passes/memory/memory_share.cc b/passes/memory/memory_share.cc index 69f3e739..140a4184 100644 --- a/passes/memory/memory_share.cc +++ b/passes/memory/memory_share.cc @@ -134,6 +134,7 @@ struct MemoryShareWorker log("Consolidating write ports of memory %s by address:\n", log_id(memid)); std::map last_port_by_addr; + std::vector> active_bits_on_port; bool cache_clk_enable = false; bool cache_clk_polarity = false; @@ -161,11 +162,27 @@ struct MemoryShareWorker log(" Port %d (%s) has addr %s.\n", i, log_id(cell), log_signal(addr)); + log(" Active bits: "); + std::vector en_bits = sigmap(cell->connections.at("\\EN")); + active_bits_on_port.push_back(std::vector(en_bits.size())); + for (int k = int(en_bits.size())-1; k >= 0; k--) { + active_bits_on_port[i][k] = en_bits[k].wire != NULL || en_bits[k].data != RTLIL::State::S0; + log("%c", active_bits_on_port[i][k] ? '1' : '0'); + } + log("\n"); + if (last_port_by_addr.count(addr)) { int last_i = last_port_by_addr.at(addr); log(" Merging port %d into this one.\n", last_i); + bool found_overlapping_bits = false; + for (int k = 0; k < int(en_bits.size()); k++) { + if (active_bits_on_port[i][k] && active_bits_on_port[last_i][k]) + found_overlapping_bits = true; + active_bits_on_port[i][k] = active_bits_on_port[i][k] || active_bits_on_port[last_i][k]; + } + // Force this ports addr input to addr directly (skip don't care muxes) cell->connections.at("\\ADDR") = addr; @@ -181,16 +198,35 @@ struct MemoryShareWorker if (wr_ports[j] == NULL) continue; - RTLIL::SigSpec is_same_addr = module->new_wire(1, NEW_ID); - module->addEq(NEW_ID, addr, wr_ports[j]->connections.at("\\ADDR"), is_same_addr); - merged_en = mask_en_grouped(is_same_addr, merged_en, sigmap(wr_ports[j]->connections.at("\\EN"))); + for (int k = 0; k < int(en_bits.size()); k++) + if (active_bits_on_port[i][k] && active_bits_on_port[j][k]) + goto found_overlapping_bits_i_j; + + if (0) { + found_overlapping_bits_i_j: + log(" Creating collosion-detect logic for port %d.\n", j); + RTLIL::SigSpec is_same_addr = module->new_wire(1, NEW_ID); + module->addEq(NEW_ID, addr, wr_ports[j]->connections.at("\\ADDR"), is_same_addr); + merged_en = mask_en_grouped(is_same_addr, merged_en, sigmap(wr_ports[j]->connections.at("\\EN"))); + } } // Then we need to merge the (masked) EN and the DATA signals. // Note that we intentionally do not use sigmap() on the DATA ports. RTLIL::SigSpec merged_data = wr_ports[last_i]->connections.at("\\DATA"); - merge_en_data(merged_en, merged_data, sigmap(cell->connections.at("\\EN")), cell->connections.at("\\DATA")); + if (found_overlapping_bits) { + log(" Creating logic for merging DATA and EN ports.\n"); + merge_en_data(merged_en, merged_data, sigmap(cell->connections.at("\\EN")), cell->connections.at("\\DATA")); + } else { + for (int k = 0; k < int(en_bits.size()); k++) + if (!active_bits_on_port[last_i][k]) { + merged_en.replace(k, cell->connections.at("\\EN").extract(k, 1)); + merged_data.replace(k, cell->connections.at("\\DATA").extract(k, 1)); + } + merged_en.optimize(); + merged_data.optimize(); + } // Connect the new EN and DATA signals and remove the old write port. @@ -200,6 +236,13 @@ struct MemoryShareWorker module->cells.erase(wr_ports[last_i]->name); delete wr_ports[last_i]; wr_ports[last_i] = NULL; + + log(" Active bits: "); + std::vector en_bits = sigmap(cell->connections.at("\\EN")); + active_bits_on_port.push_back(std::vector(en_bits.size())); + for (int k = int(en_bits.size())-1; k >= 0; k--) + log("%c", active_bits_on_port[i][k] ? '1' : '0'); + log("\n"); } last_port_by_addr[addr] = i; -- cgit v1.2.3