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Improved FSM one-hot encoding, added binary encoding

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This commit is contained in:
Clifford Wolf 2013-05-24 14:39:19 +02:00
parent ed0e2f7a6f
commit 66bc46b30b
3 changed files with 83 additions and 42 deletions
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8
passes/fsm/fsm.cc
View file

@ -56,6 +56,7 @@ struct FsmPass : public Pass {
log(" -expand, -norecode, -export, -nomap\n");
log(" enable or disable passes as indicated above\n");
log("\n");
log(" -encoding tye\n");
log(" -fm_set_fsm_file file\n");
log(" passed through to fsm_recode pass\n");
log("\n");
@ -67,6 +68,7 @@ struct FsmPass : public Pass {
bool flag_expand = false;
bool flag_export = false;
std::string fm_set_fsm_file_opt;
std::string encoding_opt;
log_header("Executing FSM pass (extract and optimize FSM).\n");
log_push();
@ -78,6 +80,10 @@ struct FsmPass : public Pass {
fm_set_fsm_file_opt = " -fm_set_fsm_file " + args[++argidx];
continue;
}
if (arg == "-encoding" && argidx+1 < args.size() && fm_set_fsm_file_opt.empty()) {
encoding_opt = " -encoding " + args[++argidx];
continue;
}
if (arg == "-norecode") {
flag_norecode = true;
continue;
@ -112,7 +118,7 @@ struct FsmPass : public Pass {
}
if (!flag_norecode)
Pass::call(design, "fsm_recode" + fm_set_fsm_file_opt);
Pass::call(design, "fsm_recode" + fm_set_fsm_file_opt + encoding_opt);
Pass::call(design, "fsm_info");
if (!flag_nomap)

16
passes/fsm/fsm_map.cc
View file

@ -77,11 +77,13 @@ static void implement_pattern_cache(RTLIL::Module *module, std::map<RTLIL::Const
and_sig.append(RTLIL::SigSpec(eq_wire));
}
if (or_sig.width < num_states-int(fullstate_cache.size()))
{
if (or_sig.width == 1)
{
and_sig.append(or_sig);
}
else if (or_sig.width < num_states && int(it.second.size()) < num_states)
else
{
RTLIL::Wire *or_wire = new RTLIL::Wire;
or_wire->name = NEW_ID;
@ -99,6 +101,7 @@ static void implement_pattern_cache(RTLIL::Module *module, std::map<RTLIL::Const
and_sig.append(RTLIL::SigSpec(or_wire));
}
}
switch (and_sig.width)
{
@ -131,7 +134,7 @@ static void implement_pattern_cache(RTLIL::Module *module, std::map<RTLIL::Const
cases_vector.append(RTLIL::SigSpec(1, 1));
break;
default:
assert(!"This should never happen!");
log_abort();
}
}
@ -184,6 +187,9 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module)
state_dff->type = "$adff";
state_dff->parameters["\\ARST_POLARITY"] = fsm_cell->parameters["\\ARST_POLARITY"];
state_dff->parameters["\\ARST_VALUE"] = fsm_data.state_table[fsm_data.reset_state];
for (auto &bit : state_dff->parameters["\\ARST_VALUE"].bits)
if (bit != RTLIL::State::S1)
bit = RTLIL::State::S0;
state_dff->connections["\\ARST"] = fsm_cell->connections["\\ARST"];
}
state_dff->parameters["\\WIDTH"] = RTLIL::Const(fsm_data.state_bits);
@ -221,7 +227,6 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module)
}
else
{
if (sig_b.as_bool() || sig_b.width != fsm_data.state_bits)
encoding_is_onehot = false;
RTLIL::Cell *eq_cell = new RTLIL::Cell;
@ -266,6 +271,7 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module)
if (encoding_is_onehot)
{
RTLIL::SigSpec next_state_sig(RTLIL::State::Sm, next_state_wire->width);
for (size_t i = 0; i < fsm_data.state_table.size(); i++) {
RTLIL::Const state = fsm_data.state_table[i];
int bit_idx = -1;
@ -273,8 +279,10 @@ static void map_fsm(RTLIL::Cell *fsm_cell, RTLIL::Module *module)
if (state.bits[j] == RTLIL::State::S1)
bit_idx = j;
if (bit_idx >= 0)
module->connections.push_back(RTLIL::SigSig(RTLIL::SigSpec(next_state_wire, 1, bit_idx), RTLIL::SigSpec(next_state_onehot, 1, i)));
next_state_sig.replace(bit_idx, RTLIL::SigSpec(next_state_onehot, 1, i));
}
log_assert(!next_state_sig.has_marked_bits());
module->connections.push_back(RTLIL::SigSig(next_state_wire, next_state_sig));
}
else
{

61
passes/fsm/fsm_recode.cc
View file

@ -23,6 +23,7 @@
#include "kernel/consteval.h"
#include "kernel/celltypes.h"
#include "fsmdata.h"
#include "math.h"
#include <string.h>
static void fm_set_fsm_print(RTLIL::Cell *cell, RTLIL::Module *module, FsmData &fsm_data, const char *prefix, FILE *f)
@ -46,31 +47,50 @@ static void fm_set_fsm_print(RTLIL::Cell *cell, RTLIL::Module *module, FsmData &
prefix, RTLIL::unescape_id(module->name).c_str());
}
static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fsm_file)
static void fsm_recode(RTLIL::Cell *cell, RTLIL::Module *module, FILE *fm_set_fsm_file, std::string default_encoding)
{
std::string encoding = cell->attributes.count("\\fsm_encoding") ? cell->attributes.at("\\fsm_encoding").str : "auto";
log("Recoding FSM `%s' from module `%s' using `%s' encoding:\n", cell->name.c_str(), module->name.c_str(), encoding.c_str());
if (encoding != "none" && encoding != "one-hot" && encoding != "binary") {
if (encoding != "auto")
log(" unkown encoding `%s': using auto (%s) instead.\n", encoding.c_str(), default_encoding.c_str());
encoding = default_encoding;
}
if (encoding == "none") {
log(" nothing to do for encoding `none'.\n");
return;
}
FsmData fsm_data;
fsm_data.copy_from_cell(cell);
log("Recoding FSM `%s' from module `%s':\n", cell->name.c_str(), module->name.c_str());
if (fm_set_fsm_file != NULL)
fm_set_fsm_print(cell, module, fsm_data, "r", fm_set_fsm_file);
if (encoding == "one-hot") {
fsm_data.state_bits = fsm_data.state_table.size();
if (fsm_data.reset_state >= 0)
fsm_data.state_bits--;
} else
if (encoding == "auto" || encoding == "binary") {
fsm_data.state_bits = ceil(log2(fsm_data.state_table.size()));
} else
log_error("FSM encoding `%s' is not supported!\n", encoding.c_str());
int bit_pos = 0;
for (size_t i = 0; i < fsm_data.state_table.size(); i++)
int state_idx_counter = fsm_data.reset_state >= 0 ? 1 : 0;
for (int i = 0; i < int(fsm_data.state_table.size()); i++)
{
int state_idx = fsm_data.reset_state == i ? 0 : state_idx_counter++;
RTLIL::Const new_code;
if (int(i) == fsm_data.reset_state)
new_code = RTLIL::Const(RTLIL::State::S0, fsm_data.state_bits);
else {
RTLIL::Const state_code(RTLIL::State::Sa, fsm_data.state_bits);
state_code.bits[bit_pos++] = RTLIL::State::S1;
new_code = state_code;
}
if (encoding == "one-hot") {
new_code = RTLIL::Const(RTLIL::State::Sa, fsm_data.state_bits);
new_code.bits[state_idx] = RTLIL::State::S1;
} else
if (encoding == "auto" || encoding == "binary") {
new_code = RTLIL::Const(state_idx, fsm_data.state_bits);
} else
log_abort();
log(" %s -> %s\n", fsm_data.state_table[i].as_string().c_str(), new_code.as_string().c_str());
fsm_data.state_table[i] = new_code;
@ -88,10 +108,12 @@ struct FsmRecodePass : public Pass {
{
// |---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|---v---|
log("\n");
log(" fsm_recode [-fm_set_fsm_file file] [selection]\n");
log(" fsm_recode [-encoding type] [-fm_set_fsm_file file] [selection]\n");
log("\n");
log("This pass reassign the state encodings for FSM cells. At the moment only\n");
log("one-hot encoding is supported.\n");
log("one-hot encoding and binary encoding is supported. The option -encoding\n");
log("can be used to specify the encoding scheme used for FSMs without the\n");
log("`fsm_encoding' attribute (or with the attribute set to `auto'.\n");
log("\n");
log("The option -fm_set_fsm_file can be used to generate a file containing the\n");
log("mapping from old to new FSM encoding in form of Synopsys Formality set_fsm_*\n");
@ -101,6 +123,7 @@ struct FsmRecodePass : public Pass {
virtual void execute(std::vector<std::string> args, RTLIL::Design *design)
{
FILE *fm_set_fsm_file = NULL;
std::string default_encoding = "one-hot";
log_header("Executing FSM_RECODE pass (re-assigning FSM state encoding).\n");
size_t argidx;
@ -112,6 +135,10 @@ struct FsmRecodePass : public Pass {
log_error("Can't open fm_set_fsm_file `%s' for writing: %s\n", args[argidx].c_str(), strerror(errno));
continue;
}
if (arg == "-encoding" && argidx+1 < args.size() && fm_set_fsm_file == NULL) {
default_encoding = args[++argidx];
continue;
}
break;
}
extra_args(args, argidx, design);
@ -120,7 +147,7 @@ struct FsmRecodePass : public Pass {
if (design->selected(mod_it.second))
for (auto &cell_it : mod_it.second->cells)
if (cell_it.second->type == "$fsm" && design->selected(mod_it.second, cell_it.second))
fsm_recode(cell_it.second, mod_it.second, fm_set_fsm_file);
fsm_recode(cell_it.second, mod_it.second, fm_set_fsm_file, default_encoding);
if (fm_set_fsm_file != NULL)
fclose(fm_set_fsm_file);