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author | Eddie Hung <eddie@fpgeh.com> | 2019-06-21 17:13:41 -0700 |
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committer | GitHub <noreply@github.com> | 2019-06-21 17:13:41 -0700 |
commit | e01bab6c6437f7e3072e10beaec558d3f71c3e9e (patch) | |
tree | 7a87cd0af1a80252aced884580166cf56d1dc7eb /passes/techmap | |
parent | e66481497155edd8af855df268befeabe3e87f7e (diff) | |
parent | ec979475e7f6bce65a4b6768cc3488a3ab02826d (diff) | |
download | yosys-e01bab6c6437f7e3072e10beaec558d3f71c3e9e.tar.gz yosys-e01bab6c6437f7e3072e10beaec558d3f71c3e9e.tar.bz2 yosys-e01bab6c6437f7e3072e10beaec558d3f71c3e9e.zip |
Merge pull request #1108 from YosysHQ/clifford/fix1091
Add support for partial matches to muxcover
Diffstat (limited to 'passes/techmap')
-rw-r--r-- | passes/techmap/muxcover.cc | 144 |
1 files changed, 99 insertions, 45 deletions
diff --git a/passes/techmap/muxcover.cc b/passes/techmap/muxcover.cc index 8e44be148..b0722134e 100644 --- a/passes/techmap/muxcover.cc +++ b/passes/techmap/muxcover.cc @@ -23,6 +23,7 @@ USING_YOSYS_NAMESPACE PRIVATE_NAMESPACE_BEGIN +#define COST_DMUX 90 #define COST_MUX2 100 #define COST_MUX4 220 #define COST_MUX8 460 @@ -57,7 +58,9 @@ struct MuxcoverWorker bool use_mux8; bool use_mux16; bool nodecode; + bool nopartial; + int cost_dmux; int cost_mux2; int cost_mux4; int cost_mux8; @@ -69,6 +72,8 @@ struct MuxcoverWorker use_mux8 = false; use_mux16 = false; nodecode = false; + nopartial = false; + cost_dmux = COST_DMUX; cost_mux2 = COST_MUX2; cost_mux4 = COST_MUX4; cost_mux8 = COST_MUX8; @@ -133,13 +138,20 @@ struct MuxcoverWorker log(" Finished treeification: Found %d trees.\n", GetSize(tree_list)); } - bool follow_muxtree(SigBit &ret_bit, tree_t &tree, SigBit bit, const char *path) + bool follow_muxtree(SigBit &ret_bit, tree_t &tree, SigBit bit, const char *path, bool first_layer = true) { if (*path) { - if (tree.muxes.count(bit) == 0) - return false; + if (tree.muxes.count(bit) == 0) { + if (first_layer || nopartial) + return false; + if (path[0] == 'S') + ret_bit = State::Sx; + else + ret_bit = bit; + return true; + } char port_name[3] = {'\\', *path, 0}; - return follow_muxtree(ret_bit, tree, sigmap(tree.muxes.at(bit)->getPort(port_name)), path+1); + return follow_muxtree(ret_bit, tree, sigmap(tree.muxes.at(bit)->getPort(port_name)), path+1, false); } else { ret_bit = bit; return true; @@ -148,7 +160,7 @@ struct MuxcoverWorker int prepare_decode_mux(SigBit &A, SigBit B, SigBit sel, SigBit bit) { - if (A == B) + if (A == B || sel == State::Sx) return 0; tuple<SigBit, SigBit, SigBit> key(A, B, sel); @@ -166,7 +178,10 @@ struct MuxcoverWorker if (std::get<2>(entry)) return 0; - return cost_mux2 / GetSize(std::get<1>(entry)); + if (A == State::Sx || B == State::Sx) + return 0; + + return cost_dmux / GetSize(std::get<1>(entry)); } void implement_decode_mux(SigBit ctrl_bit) @@ -183,9 +198,32 @@ struct MuxcoverWorker implement_decode_mux(std::get<0>(key)); implement_decode_mux(std::get<1>(key)); - module->addMuxGate(NEW_ID, std::get<0>(key), std::get<1>(key), std::get<2>(key), ctrl_bit); + if (std::get<0>(key) == State::Sx) { + module->addBufGate(NEW_ID, std::get<1>(key), ctrl_bit); + } else if (std::get<1>(key) == State::Sx) { + module->addBufGate(NEW_ID, std::get<0>(key), ctrl_bit); + } else { + module->addMuxGate(NEW_ID, std::get<0>(key), std::get<1>(key), std::get<2>(key), ctrl_bit); + decode_mux_counter++; + } std::get<2>(entry) = true; - decode_mux_counter++; + } + + void find_best_covers(tree_t &tree, const vector<SigBit> &bits) + { + for (auto bit : bits) + find_best_cover(tree, bit); + } + + int sum_best_covers(tree_t &tree, const vector<SigBit> &bits) + { + int sum = 0; + for (auto bit : pool<SigBit>(bits.begin(), bits.end())) { + int cost = tree.newmuxes.at(bit).cost; + log_debug(" Best cost for %s: %d\n", log_signal(bit), cost); + sum += cost; + } + return sum; } int find_best_cover(tree_t &tree, SigBit bit) @@ -218,9 +256,13 @@ struct MuxcoverWorker mux.inputs.push_back(B); mux.selects.push_back(S1); + find_best_covers(tree, mux.inputs); + log_debug(" Decode cost for mux2 at %s: %d\n", log_signal(bit), mux.cost); + mux.cost += cost_mux2; - mux.cost += find_best_cover(tree, A); - mux.cost += find_best_cover(tree, B); + mux.cost += sum_best_covers(tree, mux.inputs); + + log_debug(" Cost of mux2 at %s: %d\n", log_signal(bit), mux.cost); best_mux = mux; } @@ -256,13 +298,15 @@ struct MuxcoverWorker mux.selects.push_back(S1); mux.selects.push_back(T1); + find_best_covers(tree, mux.inputs); + log_debug(" Decode cost for mux4 at %s: %d\n", log_signal(bit), mux.cost); + mux.cost += cost_mux4; - mux.cost += find_best_cover(tree, A); - mux.cost += find_best_cover(tree, B); - mux.cost += find_best_cover(tree, C); - mux.cost += find_best_cover(tree, D); + mux.cost += sum_best_covers(tree, mux.inputs); - if (best_mux.cost > mux.cost) + log_debug(" Cost of mux4 at %s: %d\n", log_signal(bit), mux.cost); + + if (best_mux.cost >= mux.cost) best_mux = mux; } } @@ -319,17 +363,15 @@ struct MuxcoverWorker mux.selects.push_back(T1); mux.selects.push_back(U1); + find_best_covers(tree, mux.inputs); + log_debug(" Decode cost for mux8 at %s: %d\n", log_signal(bit), mux.cost); + mux.cost += cost_mux8; - mux.cost += find_best_cover(tree, A); - mux.cost += find_best_cover(tree, B); - mux.cost += find_best_cover(tree, C); - mux.cost += find_best_cover(tree, D); - mux.cost += find_best_cover(tree, E); - mux.cost += find_best_cover(tree, F); - mux.cost += find_best_cover(tree, G); - mux.cost += find_best_cover(tree, H); - - if (best_mux.cost > mux.cost) + mux.cost += sum_best_covers(tree, mux.inputs); + + log_debug(" Cost of mux8 at %s: %d\n", log_signal(bit), mux.cost); + + if (best_mux.cost >= mux.cost) best_mux = mux; } } @@ -423,25 +465,15 @@ struct MuxcoverWorker mux.selects.push_back(U1); mux.selects.push_back(V1); + find_best_covers(tree, mux.inputs); + log_debug(" Decode cost for mux16 at %s: %d\n", log_signal(bit), mux.cost); + mux.cost += cost_mux16; - mux.cost += find_best_cover(tree, A); - mux.cost += find_best_cover(tree, B); - mux.cost += find_best_cover(tree, C); - mux.cost += find_best_cover(tree, D); - mux.cost += find_best_cover(tree, E); - mux.cost += find_best_cover(tree, F); - mux.cost += find_best_cover(tree, G); - mux.cost += find_best_cover(tree, H); - mux.cost += find_best_cover(tree, I); - mux.cost += find_best_cover(tree, J); - mux.cost += find_best_cover(tree, K); - mux.cost += find_best_cover(tree, L); - mux.cost += find_best_cover(tree, M); - mux.cost += find_best_cover(tree, N); - mux.cost += find_best_cover(tree, O); - mux.cost += find_best_cover(tree, P); - - if (best_mux.cost > mux.cost) + mux.cost += sum_best_covers(tree, mux.inputs); + + log_debug(" Cost of mux16 at %s: %d\n", log_signal(bit), mux.cost); + + if (best_mux.cost >= mux.cost) best_mux = mux; } } @@ -537,6 +569,7 @@ struct MuxcoverWorker void treecover(tree_t &tree) { int count_muxes_by_type[4] = {0, 0, 0, 0}; + log_debug(" Searching for best cover for tree at %s.\n", log_signal(tree.root)); find_best_cover(tree, tree.root); implement_best_cover(tree, tree.root, count_muxes_by_type); log(" Replaced tree at %s: %d MUX2, %d MUX4, %d MUX8, %d MUX16\n", log_signal(tree.root), @@ -553,12 +586,13 @@ struct MuxcoverWorker log(" Covering trees:\n"); - // pre-fill cache of decoder muxes - if (!nodecode) + if (!nodecode) { + log_debug(" Populating cache of decoder muxes.\n"); for (auto &tree : tree_list) { find_best_cover(tree, tree.root); tree.newmuxes.clear(); } + } for (auto &tree : tree_list) treecover(tree); @@ -584,11 +618,19 @@ struct MuxcoverPass : public Pass { log(" Default costs: $_MUX_ = %d, $_MUX4_ = %d,\n", COST_MUX2, COST_MUX4); log(" $_MUX8_ = %d, $_MUX16_ = %d\n", COST_MUX8, COST_MUX16); log("\n"); + log(" -dmux=cost\n"); + log(" Use the specified cost for $_MUX_ cells used in decoders.\n"); + log(" Default cost: %d\n", COST_DMUX); + log("\n"); log(" -nodecode\n"); log(" Do not insert decoder logic. This reduces the number of possible\n"); log(" substitutions, but guarantees that the resulting circuit is not\n"); log(" less efficient than the original circuit.\n"); log("\n"); + log(" -nopartial\n"); + log(" Do not consider mappings that use $_MUX<N>_ to select from less\n"); + log(" than <N> different signals.\n"); + log("\n"); } void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE { @@ -598,6 +640,8 @@ struct MuxcoverPass : public Pass { bool use_mux8 = false; bool use_mux16 = false; bool nodecode = false; + bool nopartial = false; + int cost_dmux = COST_DMUX; int cost_mux4 = COST_MUX4; int cost_mux8 = COST_MUX8; int cost_mux16 = COST_MUX16; @@ -630,10 +674,18 @@ struct MuxcoverPass : public Pass { } continue; } + if (arg.size() >= 6 && arg.substr(0,6) == "-dmux=") { + cost_dmux = atoi(arg.substr(6).c_str()); + continue; + } if (arg == "-nodecode") { nodecode = true; continue; } + if (arg == "-nopartial") { + nopartial = true; + continue; + } break; } extra_args(args, argidx, design); @@ -650,10 +702,12 @@ struct MuxcoverPass : public Pass { worker.use_mux4 = use_mux4; worker.use_mux8 = use_mux8; worker.use_mux16 = use_mux16; + worker.cost_dmux = cost_dmux; worker.cost_mux4 = cost_mux4; worker.cost_mux8 = cost_mux8; worker.cost_mux16 = cost_mux16; worker.nodecode = nodecode; + worker.nopartial = nopartial; worker.run(); } } |