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ice40: Move spliceLUT back to pack.cc

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This commit is contained in:
Sergiusz Bazanski 2018-07-24 01:24:07 +01:00
parent 1d3147e26a
commit 065ea95eab
3 changed files with 53 additions and 56 deletions
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49
ice40/arch.cc
View File

@ -806,53 +806,4 @@ void Arch::assignCellInfo(CellInfo *cell)
}
}
std::unique_ptr<CellInfo> Arch::spliceLUT(CellInfo *ci, IdString portId, bool onlyNonLUTs)
{
auto port = ci->ports[portId];
NPNR_ASSERT(port.net != nullptr);
// Create pass-through LUT.
std::unique_ptr<CellInfo> pt =
create_ice_cell(getCtx(), id("ICESTORM_LC"), ci->name.str(this) + "$nextpnr_ice40_pack_pll_lc");
pt->params[id("LUT_INIT")] = "255"; // output is always I3
// Create LUT output net.
std::unique_ptr<NetInfo> out_net = std::unique_ptr<NetInfo>(new NetInfo);
out_net->name = id(ci->name.str(this) + "$nextnr_ice40_pack_pll_net");
out_net->driver.cell = pt.get();
out_net->driver.port = id("O");
pt->ports.at(id("O")).net = out_net.get();
// New users of the original cell's port
std::vector<PortRef> new_users;
for (const auto &user : port.net->users) {
if (onlyNonLUTs && user.cell->type == id("ICESTORM_LC")) {
new_users.push_back(user);
continue;
}
// Rewrite pointer into net in user.
user.cell->ports[user.port].net = out_net.get();
// Add user to net.
PortRef pr;
pr.cell = user.cell;
pr.port = user.port;
out_net->users.push_back(pr);
}
// Add LUT to new users.
PortRef pr;
pr.cell = pt.get();
pr.port = id("I3");
new_users.push_back(pr);
pt->ports.at(id("I3")).net = port.net;
// Replace users of the original net.
port.net->users = new_users;
nets[out_net->name] = std::move(out_net);
return pt;
}
NEXTPNR_NAMESPACE_END

5
ice40/arch.h
View File

@ -746,11 +746,6 @@ struct Arch : BaseCtx
IdString id_cen, id_clk, id_sr;
IdString id_i0, id_i1, id_i2, id_i3;
IdString id_dff_en, id_neg_clk;
// -------------------------------------------------
// Insert a LUT/LC in between a given output port of a cell and all its' users.
std::unique_ptr<CellInfo> spliceLUT(CellInfo *ci, IdString portId, bool onlyNonLUTs);
};
NEXTPNR_NAMESPACE_END

55
ice40/pack.cc
View File

@ -537,6 +537,57 @@ static void promote_globals(Context *ctx)
}
}
// spliceLUT adds a pass-through LUT LC between the given cell's output port
// and either all users or only non_LUT users.
static std::unique_ptr<CellInfo> spliceLUT(Context *ctx, CellInfo *ci, IdString portId, bool onlyNonLUTs)
{
auto port = ci->ports[portId];
NPNR_ASSERT(port.net != nullptr);
// Create pass-through LUT.
std::unique_ptr<CellInfo> pt =
create_ice_cell(ctx, ctx->id("ICESTORM_LC"), ci->name.str(ctx) + "$nextpnr_ice40_pack_pll_lc");
pt->params[ctx->id("LUT_INIT")] = "255"; // output is always I3
// Create LUT output net.
std::unique_ptr<NetInfo> out_net = std::unique_ptr<NetInfo>(new NetInfo);
out_net->name = ctx->id(ci->name.str(ctx) + "$nextnr_ice40_pack_pll_net");
out_net->driver.cell = pt.get();
out_net->driver.port = ctx->id("O");
pt->ports.at(ctx->id("O")).net = out_net.get();
// New users of the original cell's port
std::vector<PortRef> new_users;
for (const auto &user : port.net->users) {
if (onlyNonLUTs && user.cell->type == ctx->id("ICESTORM_LC")) {
new_users.push_back(user);
continue;
}
// Rewrite pointer into net in user.
user.cell->ports[user.port].net = out_net.get();
// Add user to net.
PortRef pr;
pr.cell = user.cell;
pr.port = user.port;
out_net->users.push_back(pr);
}
// Add LUT to new users.
PortRef pr;
pr.cell = pt.get();
pr.port = ctx->id("I3");
new_users.push_back(pr);
pt->ports.at(ctx->id("I3")).net = port.net;
// Replace users of the original net.
port.net->users = new_users;
ctx->nets[out_net->name] = std::move(out_net);
return pt;
}
// Pack special functions
static void pack_special(Context *ctx)
{
@ -674,12 +725,12 @@ static void pack_special(Context *ctx)
} else if (found_lut && !all_luts && lut_count < 8) {
// Strategy: create a pass-through LUT, move all non-LUT users behind it.
log_info(" LUT strategy for %s: move non-LUT users to new LUT\n", port.name.c_str(ctx));
auto pt = ctx->spliceLUT(packed.get(), port.name, true);
auto pt = spliceLUT(ctx, packed.get(), port.name, true);
new_cells.push_back(std::move(pt));
} else {
// Strategy: create a pass-through LUT, move every user behind it.
log_info(" LUT strategy for %s: move all users to new LUT\n", port.name.c_str(ctx));
auto pt = ctx->spliceLUT(packed.get(), port.name, false);
auto pt = spliceLUT(ctx, packed.get(), port.name, false);
new_cells.push_back(std::move(pt));
}