backends/cxxrtl/cxxrtl_vcd.h

   1 /*
   2  *  yosys -- Yosys Open SYnthesis Suite
   3  *
   4  *  Copyright (C) 2020  whitequark <whitequark@whitequark.org>
   5  *
   6  *  Permission to use, copy, modify, and/or distribute this software for any
   7  *  purpose with or without fee is hereby granted.
   8  *
   9  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  10  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  11  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  12  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  13  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  14  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  15  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  16  *
  17  */
  18
  19 #ifndef CXXRTL_VCD_H
  20 #define CXXRTL_VCD_H
  21
  22 #include <backends/cxxrtl/cxxrtl.h>
  23
  24 namespace cxxrtl {
  25
  26 class vcd_writer {
  27         struct variable {
  28                 size_t ident;
  29                 size_t width;
  30                 chunk_t *curr;
  31                 size_t prev_off;
  32         };
  33
  34         std::vector<std::string> current_scope;
  35         std::vector<variable> variables;
  36         std::vector<chunk_t> cache;
  37         bool streaming = false;
  38
  39         void emit_timescale(unsigned number, const std::string &unit) {
  40                 assert(!streaming);
  41                 assert(number == 1 || number == 10 || number == 100);
  42                 assert(unit == "s" || unit == "ms" || unit == "us" ||
  43                        unit == "ns" || unit == "ps" || unit == "fs");
  44                 buffer += "$timescale " + std::to_string(number) + " " + unit + " $end\n";
  45         }
  46
  47         void emit_scope(const std::vector<std::string> &scope) {
  48                 assert(!streaming);
  49                 while (current_scope.size() > scope.size() ||
  50                        (current_scope.size() > 0 &&
  51                         current_scope[current_scope.size() - 1] != scope[current_scope.size() - 1])) {
  52                         buffer += "$upscope $end\n";
  53                         current_scope.pop_back();
  54                 }
  55                 while (current_scope.size() < scope.size()) {
  56                         buffer += "$scope module " + scope[current_scope.size()] + " $end\n";
  57                         current_scope.push_back(scope[current_scope.size()]);
  58                 }
  59         }
  60
  61         void emit_ident(size_t ident) {
  62                 do {
  63                         buffer += '!' + ident % 94; // "base94"
  64                         ident /= 94;
  65                 } while (ident != 0);
  66         }
  67
  68         void emit_var(const variable &var, const std::string &type, const std::string &name) {
  69                 assert(!streaming);
  70                 buffer += "$var " + type + " " + std::to_string(var.width) + " ";
  71                 emit_ident(var.ident);
  72                 buffer += " " + name + " $end\n";
  73         }
  74
  75         void emit_enddefinitions() {
  76                 assert(!streaming);
  77                 buffer += "$enddefinitions $end\n";
  78                 streaming = true;
  79         }
  80
  81         void emit_time(uint64_t timestamp) {
  82                 assert(streaming);
  83                 buffer += "#" + std::to_string(timestamp) + "\n";
  84         }
  85
  86         void emit_scalar(const variable &var) {
  87                 assert(streaming);
  88                 assert(var.width == 1);
  89                 buffer += (*var.curr ? '1' : '0');
  90                 emit_ident(var.ident);
  91                 buffer += '\n';
  92         }
  93
  94         void emit_vector(const variable &var) {
  95                 assert(streaming);
  96                 buffer += 'b';
  97                 for (size_t bit = var.width - 1; bit != (size_t)-1; bit--) {
  98                         bool bit_curr = var.curr[bit / (8 * sizeof(chunk_t))] & (1 << (bit % (8 * sizeof(chunk_t))));
  99                         buffer += (bit_curr ? '1' : '0');
 100                 }
 101                 buffer += ' ';
 102                 emit_ident(var.ident);
 103                 buffer += '\n';
 104         }
 105
 106         void append_variable(size_t width, chunk_t *curr) {
 107                 const size_t chunks = (width + (sizeof(chunk_t) * 8 - 1)) / (sizeof(chunk_t) * 8);
 108                 variables.emplace_back(variable { variables.size(), width, curr, cache.size() });
 109                 cache.insert(cache.end(), &curr[0], &curr[chunks]);
 110         }
 111
 112         bool test_variable(const variable &var) {
 113                 const size_t chunks = (var.width + (sizeof(chunk_t) * 8 - 1)) / (sizeof(chunk_t) * 8);
 114                 if (std::equal(&var.curr[0], &var.curr[chunks], &cache[var.prev_off])) {
 115                         return false;
 116                 } else {
 117                         std::copy(&var.curr[0], &var.curr[chunks], &cache[var.prev_off]);
 118                         return true;
 119                 }
 120         }
 121
 122         static std::vector<std::string> split_hierarchy(const std::string &hier_name) {
 123                 std::vector<std::string> hierarchy;
 124                 size_t prev = 0;
 125                 while (true) {
 126                         size_t curr = hier_name.find_first_of(' ', prev + 1);
 127                         if (curr > hier_name.size())
 128                                 curr = hier_name.size();
 129                         if (curr > prev + 1)
 130                                 hierarchy.push_back(hier_name.substr(prev, curr - prev));
 131                         if (curr == hier_name.size())
 132                                 break;
 133                         prev = curr + 1;
 134                 }
 135                 return hierarchy;
 136         }
 137
 138 public:
 139         std::string buffer;
 140
 141         void timescale(unsigned number, const std::string &unit) {
 142                 emit_timescale(number, unit);
 143         }
 144
 145         void add(const std::string &hier_name, const debug_item &item) {
 146                 std::vector<std::string> scope = split_hierarchy(hier_name);
 147                 std::string name = scope.back();
 148                 scope.pop_back();
 149
 150                 emit_scope(scope);
 151                 switch (item.type) {
 152                         // Not the best naming but oh well...
 153                         case debug_item::VALUE:
 154                                 append_variable(item.width, item.curr);
 155                                 emit_var(variables.back(), "wire", name);
 156                                 break;
 157                         case debug_item::WIRE:
 158                                 append_variable(item.width, item.curr);
 159                                 emit_var(variables.back(), "reg", name);
 160                                 break;
 161                         case debug_item::MEMORY: {
 162                                 const size_t stride = (item.width + (sizeof(chunk_t) * 8 - 1)) / (sizeof(chunk_t) * 8);
 163                                 for (size_t index = 0; index < item.depth; index++) {
 164                                         chunk_t *nth_curr = &item.curr[stride * index];
 165                                         std::string nth_name = name + '[' + std::to_string(index) + ']';
 166                                         append_variable(item.width, nth_curr);
 167                                         emit_var(variables.back(), "reg", nth_name);
 168                                 }
 169                                 break;
 170                         }
 171                 }
 172         }
 173
 174         template<class Filter>
 175         void add(const debug_items &items, const Filter &filter) {
 176                 // `debug_items` is a map, so the items are already sorted in an order optimal for emitting
 177                 // VCD scope sections.
 178                 for (auto &it : items)
 179                         if (filter(it.first, it.second))
 180                                 add(it.first, it.second);
 181         }
 182
 183         void add(const debug_items &items) {
 184                 this->template add(items, [](const std::string &, const debug_item &) {
 185                         return true;
 186                 });
 187         }
 188
 189         void add_without_memories(const debug_items &items) {
 190                 this->template add(items, [](const std::string &, const debug_item &item) {
 191                         return item.type == debug_item::VALUE || item.type == debug_item::WIRE;
 192                 });
 193         }
 194
 195         void sample(uint64_t timestamp) {
 196                 bool first_sample = !streaming;
 197                 if (first_sample) {
 198                         emit_scope({});
 199                         emit_enddefinitions();
 200                 }
 201                 emit_time(timestamp);
 202                 for (auto var : variables)
 203                         if (test_variable(var) || first_sample) {
 204                                 if (var.width == 1)
 205                                         emit_scalar(var);
 206                                 else
 207                                         emit_vector(var);
 208                         }
 209         }
 210 };
 211
 212 }
 213
 214 #endif