passes/proc/proc_init.cc

   1 /*
   2  *  yosys -- Yosys Open SYnthesis Suite
   3  *
   4  *  Copyright (C) 2012  Clifford Wolf <clifford@clifford.at>
   5  *
   6  *  Permission to use, copy, modify, and/or distribute this software for any
   7  *  purpose with or without fee is hereby granted, provided that the above
   8  *  copyright notice and this permission notice appear in all copies.
   9  *
  10  *  THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  11  *  WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  12  *  MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  13  *  ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  14  *  WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  15  *  ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  16  *  OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  17  *
  18  */
  19
  20 #include "kernel/register.h"
  21 #include "kernel/sigtools.h"
  22 #include "kernel/log.h"
  23 #include <stdlib.h>
  24 #include <stdio.h>
  25
  26 USING_YOSYS_NAMESPACE
  27 PRIVATE_NAMESPACE_BEGIN
  28
  29 void proc_get_const(RTLIL::SigSpec &sig, RTLIL::CaseRule &rule)
  30 {
  31         log_assert(rule.compare.size() == 0);
  32
  33         while (1) {
  34                 RTLIL::SigSpec tmp = sig;
  35                 for (auto &it : rule.actions)
  36                         tmp.replace(it.first, it.second);
  37                 if (tmp == sig)
  38                         break;
  39                 sig = tmp;
  40         }
  41 }
  42
  43 void proc_init(RTLIL::Module *mod, RTLIL::Process *proc)
  44 {
  45         bool found_init = false;
  46
  47         for (auto &sync : proc->syncs)
  48                 if (sync->type == RTLIL::SyncType::STi)
  49                 {
  50                         found_init = true;
  51                         log("Found init rule in `%s.%s'.\n", mod->name.c_str(), proc->name.c_str());
  52
  53                         for (auto &action : sync->actions)
  54                         {
  55                                 RTLIL::SigSpec lhs = action.first;
  56                                 RTLIL::SigSpec rhs = action.second;
  57
  58                                 proc_get_const(rhs, proc->root_case);
  59
  60                                 if (!rhs.is_fully_const())
  61                                         log_cmd_error("Failed to get a constant init value for %s: %s\n", log_signal(lhs), log_signal(rhs));
  62
  63                                 int offset = 0;
  64                                 for (auto &lhs_c : lhs.chunks())
  65                                 {
  66                                         if (lhs_c.wire != nullptr)
  67                                         {
  68                                                 SigSpec valuesig = rhs.extract(offset, lhs_c.width);
  69                                                 if (!valuesig.is_fully_const())
  70                                                         log_cmd_error("Non-const initialization value: %s = %s\n", log_signal(lhs_c), log_signal(valuesig));
  71
  72                                                 Const value = valuesig.as_const();
  73                                                 Const &wireinit = lhs_c.wire->attributes["\\init"];
  74
  75                                                 while (GetSize(wireinit.bits) < lhs_c.wire->width)
  76                                                         wireinit.bits.push_back(State::Sx);
  77
  78                                                 for (int i = 0; i < lhs_c.width; i++) {
  79                                                         auto &initbit = wireinit.bits[i + lhs_c.offset];
  80                                                         if (initbit != State::Sx && initbit != value[i])
  81                                                                 log_cmd_error("Conflicting initialization values for %s.\n", log_signal(lhs_c));
  82                                                         initbit = value[i];
  83                                                 }
  84
  85                                                 log("  Set init value: %s = %s\n", log_signal(lhs_c.wire), log_signal(wireinit));
  86                                         }
  87                                         offset += lhs_c.width;
  88                                 }
  89                         }
  90                 }
  91
  92         if (found_init) {
  93                 std::vector<RTLIL::SyncRule*> new_syncs;
  94                 for (auto &sync : proc->syncs)
  95                         if (sync->type == RTLIL::SyncType::STi)
  96                                 delete sync;
  97                         else
  98                                 new_syncs.push_back(sync);
  99                 proc->syncs.swap(new_syncs);
 100         }
 101 }
 102
 103 struct ProcInitPass : public Pass {
 104         ProcInitPass() : Pass("proc_init", "convert initial block to init attributes") { }
 105         void help() YS_OVERRIDE
 106         {
 107                 //   |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
 108                 log("\n");
 109                 log("    proc_init [selection]\n");
 110                 log("\n");
 111                 log("This pass extracts the 'init' actions from processes (generated from Verilog\n");
 112                 log("'initial' blocks) and sets the initial value to the 'init' attribute on the\n");
 113                 log("respective wire.\n");
 114                 log("\n");
 115         }
 116         void execute(std::vector<std::string> args, RTLIL::Design *design) YS_OVERRIDE
 117         {
 118                 log_header(design, "Executing PROC_INIT pass (extract init attributes).\n");
 119
 120                 extra_args(args, 1, design);
 121
 122                 for (auto mod : design->modules())
 123                         if (design->selected(mod))
 124                                 for (auto &proc_it : mod->processes)
 125                                         if (design->selected(mod, proc_it.second))
 126                                                 proc_init(mod, proc_it.second);
 127         }
 128 } ProcInitPass;
 129
 130 PRIVATE_NAMESPACE_END