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authorClifford Wolf <clifford@clifford.at>2013-10-24 16:54:05 +0200
committerClifford Wolf <clifford@clifford.at>2013-10-24 16:54:05 +0200
commit628b994cf6223a03d0d57bad193675dc93e88d65 (patch)
tree56dad20ed7d83a6957aa738b59d957b1b89b814f
parente679a5d04633e0c0626057ed2760ddb9595eea5d (diff)
Added support for complex set-reset flip-flops in proc_dff
-rw-r--r--backends/autotest/autotest.cc7
-rw-r--r--passes/proc/proc_dff.cc119
-rw-r--r--tests/simple/dff_different_styles.v38
3 files changed, 147 insertions, 17 deletions
diff --git a/backends/autotest/autotest.cc b/backends/autotest/autotest.cc
index 6fd3a43c..c59e2bd1 100644
--- a/backends/autotest/autotest.cc
+++ b/backends/autotest/autotest.cc
@@ -99,6 +99,10 @@ static void autotest(FILE *f, RTLIL::Design *design)
std::map<std::string, int> signal_out;
RTLIL::Module *mod = it->second;
+
+ if (mod->get_bool_attribute("\\gentb_skip"))
+ continue;
+
int count_ports = 0;
log("Generating test bench for module `%s'.\n", it->first.c_str());
for (auto it2 = mod->wires.begin(); it2 != mod->wires.end(); it2++) {
@@ -290,7 +294,8 @@ static void autotest(FILE *f, RTLIL::Design *design)
fprintf(f, "\t// $dumpfile(\"testbench.vcd\");\n");
fprintf(f, "\t// $dumpvars(0, testbench);\n");
for (auto it = design->modules.begin(); it != design->modules.end(); it++)
- fprintf(f, "\t%s;\n", idy(it->first, "test").c_str());
+ if (!it->second->get_bool_attribute("\\gentb_skip"))
+ fprintf(f, "\t%s;\n", idy(it->first, "test").c_str());
fprintf(f, "\t$finish;\n");
fprintf(f, "end\n\n");
diff --git a/passes/proc/proc_dff.cc b/passes/proc/proc_dff.cc
index db7a59f5..2ec498fb 100644
--- a/passes/proc/proc_dff.cc
+++ b/passes/proc/proc_dff.cc
@@ -51,6 +51,117 @@ static RTLIL::SigSpec find_any_lvalue(const RTLIL::Process *proc)
return lvalue;
}
+static void gen_dffsr_complex(RTLIL::Module *mod, RTLIL::SigSpec sig_d, RTLIL::SigSpec sig_q, RTLIL::SigSpec clk, bool clk_polarity,
+ std::map<RTLIL::SigSpec, std::set<RTLIL::SyncRule*>> &async_rules, RTLIL::Process *proc)
+{
+ RTLIL::SigSpec sig_sr_set = RTLIL::SigSpec(0, sig_d.width);
+ RTLIL::SigSpec sig_sr_clr = RTLIL::SigSpec(0, sig_d.width);
+
+ for (auto &it : async_rules)
+ {
+ RTLIL::SigSpec sync_value = it.first;
+ RTLIL::SigSpec sync_value_inv;
+ RTLIL::SigSpec sync_high_signals;
+ RTLIL::SigSpec sync_low_signals;
+
+ for (auto &it2 : it.second)
+ if (it2->type == RTLIL::SyncType::ST0)
+ sync_low_signals.append(it2->signal);
+ else if (it2->type == RTLIL::SyncType::ST1)
+ sync_high_signals.append(it2->signal);
+ else
+ log_abort();
+
+ if (sync_low_signals.width > 1) {
+ RTLIL::Cell *cell = new RTLIL::Cell;
+ cell->name = NEW_ID;
+ cell->type = "$reduce_or";
+ cell->parameters["\\A_SIGNED"] = RTLIL::Const(0);
+ cell->parameters["\\A_WIDTH"] = RTLIL::Const(sync_low_signals.width);
+ cell->parameters["\\Y_WIDTH"] = RTLIL::Const(1);
+ cell->connections["\\A"] = sync_low_signals;
+ cell->connections["\\Y"] = sync_low_signals = NEW_WIRE(mod, 1);
+ mod->add(cell);
+ }
+
+ if (sync_low_signals.width > 0) {
+ RTLIL::Cell *cell = new RTLIL::Cell;
+ cell->name = NEW_ID;
+ cell->type = "$not";
+ cell->parameters["\\A_SIGNED"] = RTLIL::Const(0);
+ cell->parameters["\\A_WIDTH"] = RTLIL::Const(sync_low_signals.width);
+ cell->parameters["\\Y_WIDTH"] = RTLIL::Const(1);
+ cell->connections["\\A"] = sync_low_signals;
+ cell->connections["\\Y"] = NEW_WIRE(mod, 1);
+ sync_high_signals.append(cell->connections["\\Y"]);
+ mod->add(cell);
+ }
+
+ if (sync_high_signals.width > 1) {
+ RTLIL::Cell *cell = new RTLIL::Cell;
+ cell->name = NEW_ID;
+ cell->type = "$reduce_or";
+ cell->parameters["\\A_SIGNED"] = RTLIL::Const(0);
+ cell->parameters["\\A_WIDTH"] = RTLIL::Const(sync_high_signals.width);
+ cell->parameters["\\Y_WIDTH"] = RTLIL::Const(1);
+ cell->connections["\\A"] = sync_high_signals;
+ cell->connections["\\Y"] = sync_high_signals = NEW_WIRE(mod, 1);
+ mod->add(cell);
+ }
+
+ RTLIL::Cell *inv_cell = new RTLIL::Cell;
+ inv_cell->name = NEW_ID;
+ inv_cell->type = "$not";
+ inv_cell->parameters["\\A_SIGNED"] = RTLIL::Const(0);
+ inv_cell->parameters["\\A_WIDTH"] = RTLIL::Const(sig_d.width);
+ inv_cell->parameters["\\Y_WIDTH"] = RTLIL::Const(sig_d.width);
+ inv_cell->connections["\\A"] = sync_value;
+ inv_cell->connections["\\Y"] = sync_value_inv = NEW_WIRE(mod, sig_d.width);
+ mod->add(inv_cell);
+
+ RTLIL::Cell *mux_set_cell = new RTLIL::Cell;
+ mux_set_cell->name = NEW_ID;
+ mux_set_cell->type = "$mux";
+ mux_set_cell->parameters["\\WIDTH"] = RTLIL::Const(sig_d.width);
+ mux_set_cell->connections["\\A"] = sig_sr_set;
+ mux_set_cell->connections["\\B"] = sync_value;
+ mux_set_cell->connections["\\S"] = sync_high_signals;
+ mux_set_cell->connections["\\Y"] = sig_sr_set = NEW_WIRE(mod, sig_d.width);
+ mod->add(mux_set_cell);
+
+ RTLIL::Cell *mux_clr_cell = new RTLIL::Cell;
+ mux_clr_cell->name = NEW_ID;
+ mux_clr_cell->type = "$mux";
+ mux_clr_cell->parameters["\\WIDTH"] = RTLIL::Const(sig_d.width);
+ mux_clr_cell->connections["\\A"] = sig_sr_clr;
+ mux_clr_cell->connections["\\B"] = sync_value_inv;
+ mux_clr_cell->connections["\\S"] = sync_high_signals;
+ mux_clr_cell->connections["\\Y"] = sig_sr_clr = NEW_WIRE(mod, sig_d.width);
+ mod->add(mux_clr_cell);
+ }
+
+ std::stringstream sstr;
+ sstr << "$procdff$" << (RTLIL::autoidx++);
+
+ RTLIL::Cell *cell = new RTLIL::Cell;
+ cell->name = sstr.str();
+ cell->type = "$dffsr";
+ cell->attributes = proc->attributes;
+ cell->parameters["\\WIDTH"] = RTLIL::Const(sig_d.width);
+ cell->parameters["\\CLK_POLARITY"] = RTLIL::Const(clk_polarity, 1);
+ cell->parameters["\\SET_POLARITY"] = RTLIL::Const(true, 1);
+ cell->parameters["\\CLR_POLARITY"] = RTLIL::Const(true, 1);
+ cell->connections["\\D"] = sig_d;
+ cell->connections["\\Q"] = sig_q;
+ cell->connections["\\CLK"] = clk;
+ cell->connections["\\SET"] = sig_sr_set;
+ cell->connections["\\CLR"] = sig_sr_clr;
+ mod->add(cell);
+
+ log(" created %s cell `%s' with %s edge clock and multiple level-sensitive resets.\n",
+ cell->type.c_str(), cell->name.c_str(), clk_polarity ? "positive" : "negative");
+}
+
static void gen_dffsr(RTLIL::Module *mod, RTLIL::SigSpec sig_in, RTLIL::SigSpec sig_set, RTLIL::SigSpec sig_out,
bool clk_polarity, bool set_polarity, RTLIL::SigSpec clk, RTLIL::SigSpec set, RTLIL::Process *proc)
{
@@ -64,6 +175,7 @@ static void gen_dffsr(RTLIL::Module *mod, RTLIL::SigSpec sig_in, RTLIL::SigSpec
RTLIL::Cell *inv_set = new RTLIL::Cell;
inv_set->name = NEW_ID;
inv_set->type = "$not";
+ inv_set->parameters["\\A_SIGNED"] = RTLIL::Const(0);
inv_set->parameters["\\A_WIDTH"] = RTLIL::Const(sig_in.width);
inv_set->parameters["\\Y_WIDTH"] = RTLIL::Const(sig_in.width);
inv_set->connections["\\A"] = sig_set;
@@ -94,18 +206,16 @@ static void gen_dffsr(RTLIL::Module *mod, RTLIL::SigSpec sig_in, RTLIL::SigSpec
cell->name = sstr.str();
cell->type = "$dffsr";
cell->attributes = proc->attributes;
- mod->add(cell);
-
cell->parameters["\\WIDTH"] = RTLIL::Const(sig_in.width);
cell->parameters["\\CLK_POLARITY"] = RTLIL::Const(clk_polarity, 1);
cell->parameters["\\SET_POLARITY"] = RTLIL::Const(true, 1);
cell->parameters["\\CLR_POLARITY"] = RTLIL::Const(true, 1);
-
cell->connections["\\D"] = sig_in;
cell->connections["\\Q"] = sig_out;
cell->connections["\\CLK"] = clk;
cell->connections["\\SET"] = sig_sr_set;
cell->connections["\\CLR"] = sig_sr_clr;
+ mod->add(cell);
log(" created %s cell `%s' with %s edge clock and %s level non-const reset.\n", cell->type.c_str(), cell->name.c_str(),
clk_polarity ? "positive" : "negative", set_polarity ? "positive" : "negative");
@@ -259,7 +369,8 @@ static void proc_dff(RTLIL::Module *mod, RTLIL::Process *proc, ConstEval &ce)
if (many_async_rules.size() > 0)
{
- log_error("Multiple async resets for different values (feature under construction)!\n");
+ log("WARNING: Complex async reset for dff `%s'.\n", log_signal(sig));
+ gen_dffsr_complex(mod, insig, sig, sync_edge->signal, sync_edge->type == RTLIL::SyncType::STp, many_async_rules, proc);
}
else if (!rstval.is_fully_const() && !ce.eval(rstval))
{
diff --git a/tests/simple/dff_different_styles.v b/tests/simple/dff_different_styles.v
index db88b835..2f2737c4 100644
--- a/tests/simple/dff_different_styles.v
+++ b/tests/simple/dff_different_styles.v
@@ -65,6 +65,10 @@ always @(posedge clk, posedge arst1, posedge arst2, negedge arst3) begin
end
endmodule
+// SR-Flip-Flops are on the edge of well defined vewrilog constructs in terms of
+// simulation-implementation mismatches. The following testcases try to cover the
+// part that is defined and avoid the undefined cases.
+
module dffsr1(clk, arst, d, q);
input clk, arst, d;
output reg q;
@@ -76,16 +80,26 @@ always @(posedge clk, posedge arst) begin
end
endmodule
-// module dffsr2(clk, preset, clear, d, q);
-// input clk, preset, clear, d;
-// output reg q;
-// always @(posedge clk, posedge preset, posedge clear) begin
-// if (preset)
-// q <= 1;
-// else if (clear)
-// q <= 0;
-// else
-// q <= d;
-// end
-// endmodule
+module dffsr2(clk, preset, clear, d, q);
+input clk, preset, clear, d;
+output q;
+(* gentb_clock *)
+wire clk, preset, clear, d;
+dffsr2_sub uut (clk, preset && !clear, !preset && clear, d, q);
+endmodule
+
+(* gentb_skip *)
+module dffsr2_sub(clk, preset, clear, d, q);
+input clk, preset, clear, d;
+output reg q;
+always @(posedge clk, posedge preset, posedge clear) begin
+ if (preset)
+ q <= 1;
+ else if (clear)
+ q <= 0;
+ else
+ q <= d;
+end
+endmodule
+