From 204572d926921608b8d1c3d59e96c7f25051527d Mon Sep 17 00:00:00 2001
From: Clifford Wolf <clifford@clifford.at>
Date: Wed, 6 Nov 2013 14:12:44 +0100
Subject: Fixed handling of undef values in MUX select input in ConstEval
---
kernel/consteval.h | 90 +++++++++++++++++++++++++++++++++++-------------------
1 file changed, 58 insertions(+), 32 deletions(-)
diff --git a/kernel/consteval.h b/kernel/consteval.h
index d48771fea..a424007ef 100644
--- a/kernel/consteval.h
+++ b/kernel/consteval.h
@@ -89,8 +89,6 @@ struct ConstEval
bool eval(RTLIL::Cell *cell, RTLIL::SigSpec &undef)
{
RTLIL::SigSpec sig_a, sig_b, sig_s, sig_y;
- bool ignore_sig_a = false, ignore_sig_b = false;
- int sig_b_shift = -1;
assert(cell->connections.count("\\Y") > 0);
sig_y = values_map(assign_map(cell->connections["\\Y"]));
@@ -103,43 +101,71 @@ struct ConstEval
return false;
}
- if (cell->type == "$mux" || cell->type == "$pmux" || cell->type == "$safe_pmux" || cell->type == "$_MUX_") {
- bool found_collision = false;
- for (int i = 0; i < sig_s.width; i++)
- if (sig_s.extract(i, 1).as_bool()) {
- if (sig_b_shift >= 0)
- found_collision = true;
- sig_b_shift = i;
- ignore_sig_a = true;
- if (cell->type != "$safe_pmux")
- break;
- }
- if (found_collision) {
- sig_b_shift = -1;
- ignore_sig_a = false;
- }
- if (sig_b_shift < 0)
- ignore_sig_b = true;
- }
-
- if (!ignore_sig_a && cell->connections.count("\\A") > 0) {
+ if (cell->connections.count("\\A") > 0)
sig_a = cell->connections["\\A"];
- if (!eval(sig_a, undef, cell))
- return false;
- }
- if (!ignore_sig_b && cell->connections.count("\\B") > 0) {
+ if (cell->connections.count("\\B") > 0)
sig_b = cell->connections["\\B"];
- if (sig_b_shift >= 0)
- sig_b = sig_b.extract(sig_y.width*sig_b_shift, sig_y.width);
- if (!eval(sig_b, undef, cell))
- return false;
- }
if (cell->type == "$mux" || cell->type == "$pmux" || cell->type == "$safe_pmux" || cell->type == "$_MUX_")
- set(sig_y, sig_s.as_bool() ? sig_b.as_const() : sig_a.as_const());
+ {
+ std::vector<RTLIL::SigSpec> y_candidates;
+ int count_set_s_bits = 0;
+
+ for (int i = 0; i < sig_s.width; i++)
+ {
+ RTLIL::State s_bit = sig_s.extract(i, 1).as_const().bits.at(0);
+ RTLIL::SigSpec b_slice = sig_b.extract(sig_y.width*i, sig_y.width);
+
+ if (s_bit == RTLIL::State::Sx || s_bit == RTLIL::State::S1)
+ y_candidates.push_back(b_slice);
+
+ if (s_bit == RTLIL::State::S1)
+ count_set_s_bits++;
+ }
+
+ if (cell->type == "$safe_pmux" && count_set_s_bits > 1) {
+ y_candidates.clear();
+ count_set_s_bits = 0;
+ }
+
+ if (count_set_s_bits == 0)
+ y_candidates.push_back(sig_a);
+
+ std::vector<RTLIL::Const> y_values;
+
+ assert(y_candidates.size() > 0);
+ for (auto &yc : y_candidates) {
+ if (!eval(yc, undef, cell))
+ return false;
+ y_values.push_back(yc.as_const());
+ }
+
+ if (y_values.size() > 1)
+ {
+ std::vector<RTLIL::State> master_bits = y_values.at(0).bits;
+
+ for (size_t i = 1; i < y_values.size(); i++) {
+ std::vector<RTLIL::State> &slave_bits = y_values.at(i).bits;
+ assert(master_bits.size() == slave_bits.size());
+ for (size_t j = 0; j < master_bits.size(); j++)
+ if (master_bits[j] != slave_bits[j])
+ master_bits[j] = RTLIL::State::Sx;
+ }
+
+ set(sig_y, RTLIL::Const(master_bits));
+ }
+ else
+ set(sig_y, y_values.front());
+ }
else
+ {
+ if (sig_a.width > 0 && !eval(sig_a, undef, cell))
+ return false;
+ if (sig_b.width > 0 && !eval(sig_b, undef, cell))
+ return false;
set(sig_y, CellTypes::eval(cell, sig_a.as_const(), sig_b.as_const()));
+ }
return true;
}
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