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ice40: Fix carry packing in some degenerate cases

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Signed-off-by: David Shah <davey1576@gmail.com>
This commit is contained in:
David Shah 2018-06-29 15:10:29 +02:00
parent 1aa4be770c
commit 3b90f3698f
1 changed files with 18 additions and 23 deletions
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41
ice40/pack.cc
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@ -188,30 +188,25 @@ static void pack_carries(Context *ctx)
if (carry_ci_lc && carry_lcs.find(carry_ci_lc->name) != carry_lcs.end()) {
carry_lc = carry_ci_lc;
} else {
if (carry_lcs.empty()) {
// No LC to pack into matching I0/I1, insert a new one
std::unique_ptr<CellInfo> created_lc =
create_ice_cell(ctx, ctx->id("ICESTORM_LC"), cell.first.str(ctx) + "$CARRY");
carry_lc = created_lc.get();
created_lc->ports.at(ctx->id("I1")).net = i0_net;
if (i0_net) {
PortRef pr;
pr.cell = created_lc.get();
pr.port = ctx->id("I1");
i0_net->users.push_back(pr);
}
created_lc->ports.at(ctx->id("I2")).net = i1_net;
if (i1_net) {
PortRef pr;
pr.cell = created_lc.get();
pr.port = ctx->id("I2");
i1_net->users.push_back(pr);
}
new_cells.push_back(std::move(created_lc));
} else {
carry_lc = ctx->cells.at(*(carry_lcs.begin())).get();
// No LC to pack into matching I0/I1, insert a new one
std::unique_ptr<CellInfo> created_lc =
create_ice_cell(ctx, ctx->id("ICESTORM_LC"), cell.first.str(ctx) + "$CARRY");
carry_lc = created_lc.get();
created_lc->ports.at(ctx->id("I1")).net = i0_net;
if (i0_net) {
PortRef pr;
pr.cell = created_lc.get();
pr.port = ctx->id("I1");
i0_net->users.push_back(pr);
}
created_lc->ports.at(ctx->id("I2")).net = i1_net;
if (i1_net) {
PortRef pr;
pr.cell = created_lc.get();
pr.port = ctx->id("I2");
i1_net->users.push_back(pr);
}
new_cells.push_back(std::move(created_lc));
}
carry_lc->params[ctx->id("CARRY_ENABLE")] = "1";
replace_port(ci, ctx->id("CI"), carry_lc, ctx->id("CIN"));