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ice40: Fixing the carry packer for a larger design

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-06-27 12:43:29 +02:00
parent 53ce81343a
commit 998ab2b20a
1 changed files with 33 additions and 16 deletions
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49
ice40/pack.cc
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@ -112,6 +112,18 @@ static void pack_nonlut_ffs(Context *ctx)
} }
} }
static bool net_is_constant(const Context *ctx, NetInfo *net, bool &value)
{
if (net == nullptr)
return false;
if (net->name == ctx->id("$PACKER_GND_NET") || net->name == ctx->id("$PACKER_VCC_NET")) {
value = (net->name == ctx->id("$PACKER_VCC_NET"));
return true;
} else {
return false;
}
}
// Pack carry logic // Pack carry logic
static void pack_carries(Context *ctx) static void pack_carries(Context *ctx)
{ {
@ -124,7 +136,15 @@ static void pack_carries(Context *ctx)
CellInfo *ci = cell.second; CellInfo *ci = cell.second;
if (is_carry(ctx, ci)) { if (is_carry(ctx, ci)) {
packed_cells.insert(cell.first); packed_cells.insert(cell.first);
CellInfo *carry_ci_lc = net_only_drives(ctx, ci->ports.at(ctx->id("CI")).net, is_lc, ctx->id("I3"), false);
CellInfo *carry_ci_lc;
bool ci_value;
bool ci_const = net_is_constant(ctx, ci->ports.at(ctx->id("CI")).net, ci_value);
if (ci_const) {
carry_ci_lc = nullptr;
} else {
carry_ci_lc = net_only_drives(ctx, ci->ports.at(ctx->id("CI")).net, is_lc, ctx->id("I3"), false);
}
std::set<IdString> i0_matches, i1_matches; std::set<IdString> i0_matches, i1_matches;
NetInfo *i0_net = ci->ports.at(ctx->id("I0")).net; NetInfo *i0_net = ci->ports.at(ctx->id("I0")).net;
@ -157,20 +177,7 @@ static void pack_carries(Context *ctx)
std::set_intersection(i0_matches.begin(), i0_matches.end(), i1_matches.begin(), i1_matches.end(), std::set_intersection(i0_matches.begin(), i0_matches.end(), i1_matches.begin(), i1_matches.end(),
std::inserter(carry_lcs, carry_lcs.end())); std::inserter(carry_lcs, carry_lcs.end()));
CellInfo *carry_lc = nullptr; CellInfo *carry_lc = nullptr;
if (carry_ci_lc) { if (carry_ci_lc && carry_lcs.find(carry_ci_lc->name) != carry_lcs.end()) {
if (carry_lcs.find(carry_ci_lc->name) == carry_lcs.end()) {
if (ctx->verbose) {
for (auto i0 : i0_matches)
log_info("I0 candidate: '%s'\n", i0.c_str(ctx));
for (auto i1 : i1_matches)
log_info("I1 candidate: '%s'\n", i1.c_str(ctx));
log_info("I3 connects to: '%s'\n", carry_ci_lc->name.c_str(ctx));
}
log_error("SB_CARRY '%s' cannot be packed into any logic "
"cell (I0 and I1 connections do not match I3 "
"connection)\n",
cell.first.c_str(ctx));
}
carry_lc = carry_ci_lc; carry_lc = carry_ci_lc;
} else { } else {
if (carry_lcs.empty()) { if (carry_lcs.empty()) {
@ -195,7 +202,17 @@ static void pack_carries(Context *ctx)
new_cells.push_back(std::move(created_lc)); new_cells.push_back(std::move(created_lc));
} else { } else {
carry_lc = ctx->cells.at(*carry_lcs.begin()).get(); IdString lc_name = *carry_lcs.begin();
if (ctx->cells.find(lc_name) != ctx->cells.end()) {
carry_lc = ctx->cells.at(lc_name).get();
} else {
// Name might not be found in the Context, if it is a new cell
auto new_pack =
std::find_if(new_cells.begin(), new_cells.end(),
[lc_name](std::unique_ptr<CellInfo> &nc) { return nc->name == lc_name; });
assert(new_pack != new_cells.end());
carry_lc = new_pack->get();
}
} }
} }
carry_lc->params[ctx->id("CARRY_ENABLE")] = "1"; carry_lc->params[ctx->id("CARRY_ENABLE")] = "1";