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-rw-r--r--common/design_utils.cc3
-rw-r--r--common/router2.cc28
-rw-r--r--ecp5/arch.cc12
-rw-r--r--ecp5/bitstream.cc5
-rw-r--r--ecp5/constids.inc4
-rw-r--r--ecp5/globals.cc45
-rw-r--r--fpga_interchange/arch.cc11
-rw-r--r--fpga_interchange/arch.h6
-rw-r--r--fpga_interchange/arch_pack_io.cc70
-rw-r--r--fpga_interchange/examples/tests/CMakeLists.txt1
-rw-r--r--fpga_interchange/examples/tests/obuftds/CMakeLists.txt7
-rw-r--r--fpga_interchange/examples/tests/obuftds/basys3.xdc9
-rw-r--r--fpga_interchange/examples/tests/obuftds/obuftds.v37
-rw-r--r--fpga_interchange/examples/tests/obuftds/run.tcl14
-rw-r--r--fpga_interchange/macros.cc12
15 files changed, 193 insertions, 71 deletions
diff --git a/common/design_utils.cc b/common/design_utils.cc
index a892feaa..da5decf9 100644
--- a/common/design_utils.cc
+++ b/common/design_utils.cc
@@ -161,7 +161,8 @@ void rename_net(Context *ctx, NetInfo *net, IdString new_name)
if (net == nullptr)
return;
NPNR_ASSERT(!ctx->nets.count(new_name));
- std::swap(ctx->nets[net->name], ctx->nets[new_name]);
+ ctx->nets[new_name];
+ std::swap(ctx->nets.at(net->name), ctx->nets.at(new_name));
ctx->nets.erase(net->name);
net->name = new_name;
}
diff --git a/common/router2.cc b/common/router2.cc
index a8eea5f9..7bffc089 100644
--- a/common/router2.cc
+++ b/common/router2.cc
@@ -856,10 +856,20 @@ struct Router2
int(a.first), int(a.second), ctx->nameOf(net));
auto res2 = route_arc(t, net, a.first, a.second, is_mt, false);
// If this also fails, no choice but to give up
- if (res2 != ARC_SUCCESS)
+ if (res2 != ARC_SUCCESS) {
+ if (ctx->debug) {
+ log_info("Pre-bound routing: \n");
+ for (auto &wire_pair : net->wires) {
+ log(" %s", ctx->nameOfWire(wire_pair.first));
+ if (wire_pair.second.pip != PipId())
+ log(" %s", ctx->nameOfPip(wire_pair.second.pip));
+ log("\n");
+ }
+ }
log_error("Failed to route arc %d.%d of net '%s', from %s to %s.\n", int(a.first),
int(a.second), ctx->nameOf(net), ctx->nameOfWire(ctx->getNetinfoSourceWire(net)),
ctx->nameOfWire(ctx->getNetinfoSinkWire(net, net->users.at(a.first), a.second)));
+ }
}
}
}
@@ -968,17 +978,17 @@ struct Router2
log_error("Internal error; incomplete route tree for arc %d of net %s.\n", usr_idx, ctx->nameOf(net));
}
auto &p = wd.bound_nets.at(net->udata).second;
- if (!ctx->checkPipAvail(p)) {
+ if (ctx->checkPipAvailForNet(p, net)) {
NetInfo *bound_net = ctx->getBoundPipNet(p);
- if (bound_net != net) {
- if (ctx->verbose) {
- log_info("Failed to bind pip %s to net %s\n", ctx->nameOfPip(p), net->name.c_str(ctx));
- }
- success = false;
- break;
+ if (bound_net == nullptr) {
+ to_bind.push_back(p);
}
} else {
- to_bind.push_back(p);
+ if (ctx->verbose) {
+ log_info("Failed to bind pip %s to net %s\n", ctx->nameOfPip(p), net->name.c_str(ctx));
+ }
+ success = false;
+ break;
}
cursor = ctx->getPipSrcWire(p);
}
diff --git a/ecp5/arch.cc b/ecp5/arch.cc
index 2c04105c..34bdfa1b 100644
--- a/ecp5/arch.cc
+++ b/ecp5/arch.cc
@@ -793,6 +793,12 @@ bool Arch::getCellDelay(const CellInfo *cell, IdString fromPort, IdString toPort
return true;
}
return false;
+ } else if (cell->type == id_DCSC) {
+ if ((fromPort == id_CLK0 || fromPort == id_CLK1) && toPort == id_DCSOUT) {
+ delay = DelayQuad(0);
+ return true;
+ }
+ return false;
} else if (cell->type == id_DP16KD) {
return false;
} else if (cell->type == id_MULT18X18D) {
@@ -866,6 +872,12 @@ TimingPortClass Arch::getPortTimingClass(const CellInfo *cell, IdString port, in
if (port == id_CLKO)
return TMG_COMB_OUTPUT;
return TMG_IGNORE;
+ } else if (cell->type == id_DCSC) {
+ if (port == id_CLK0 || port == id_CLK1)
+ return TMG_COMB_INPUT;
+ if (port == id_DCSOUT)
+ return TMG_COMB_OUTPUT;
+ return TMG_IGNORE;
} else if (cell->type == id_DP16KD) {
if (port == id_CLKA || port == id_CLKB)
return TMG_CLOCK_INPUT;
diff --git a/ecp5/bitstream.cc b/ecp5/bitstream.cc
index c92de083..a544f2b7 100644
--- a/ecp5/bitstream.cc
+++ b/ecp5/bitstream.cc
@@ -1019,6 +1019,11 @@ void write_bitstream(Context *ctx, std::string base_config_file, std::string tex
tg.config.add_enum(std::string("DCC_") + belname[0] + belname.substr(4) + ".MODE", "DCCA");
cc.tilegroups.push_back(tg);
}
+ } else if (ci->type == ctx->id("DCSC")) {
+ std::set<std::string> dcs_tiles{"EBR_CMUX_LL", "EBR_CMUX_UL", "EBR_CMUX_LL_25K", "DSP_CMUX_UL"};
+ std::string tile = ctx->get_tile_by_type_loc(bel.location.y, bel.location.x, dcs_tiles);
+ std::string dcs = ctx->loc_info(bel)->bel_data[bel.index].name.get();
+ cc.tiles[tile].add_enum(dcs + ".DCSMODE", str_or_default(ci->attrs, ctx->id("DCSMODE"), "POS"));
} else if (ci->type == ctx->id("DP16KD")) {
TileGroup tg;
Loc loc = ctx->getBelLocation(ci->bel);
diff --git a/ecp5/constids.inc b/ecp5/constids.inc
index e5ec1c3e..335f822a 100644
--- a/ecp5/constids.inc
+++ b/ecp5/constids.inc
@@ -1337,3 +1337,7 @@ X(IOLOGIC_MODE_ODDRX1F)
X(IOLOGIC_MODE_ODDRX2F)
X(IOLOGIC_MODE_OREG)
X(IOLOGIC_MODE_TSREG)
+
+X(DCSC)
+X(DCSOUT)
+X(MODESEL)
diff --git a/ecp5/globals.cc b/ecp5/globals.cc
index 580d470a..8ee49c02 100644
--- a/ecp5/globals.cc
+++ b/ecp5/globals.cc
@@ -278,7 +278,7 @@ class Ecp5GlobalRouter
bool route_onto_global(NetInfo *net, int network)
{
WireId glb_src;
- NPNR_ASSERT(net->driver.cell->type == id_DCCA);
+ NPNR_ASSERT(net->driver.cell->type == id_DCCA || net->driver.cell->type == id_DCSC);
glb_src = ctx->getNetinfoSourceWire(net);
for (int quad = QUAD_UL; quad < QUAD_LR + 1; quad++) {
WireId glb_dst = get_global_wire(GlobalQuadrant(quad), network);
@@ -293,7 +293,7 @@ class Ecp5GlobalRouter
// Get DCC wirelength based on source
wirelen_t get_dcc_wirelen(CellInfo *dcc, bool &dedicated_routing)
{
- NetInfo *clki = dcc->ports.at(id_CLKI).net;
+ NetInfo *clki = dcc->ports.at((dcc->type == id_DCSC) ? id_CLK0 : id_CLKI).net;
BelId drv_bel;
const PortRef &drv = clki->driver;
dedicated_routing = false;
@@ -395,7 +395,7 @@ class Ecp5GlobalRouter
}
// Attempt to place a DCC
- void place_dcc(CellInfo *dcc)
+ void place_dcc_dcs(CellInfo *dcc)
{
BelId best_bel;
WireId best_bel_pclkcib;
@@ -403,7 +403,7 @@ class Ecp5GlobalRouter
wirelen_t best_wirelen = 9999999;
bool dedicated_routing = false;
for (auto bel : ctx->getBels()) {
- if (ctx->getBelType(bel) == id_DCCA && ctx->checkBelAvail(bel)) {
+ if (ctx->getBelType(bel) == dcc->type && ctx->checkBelAvail(bel)) {
std::string belname = ctx->loc_info(bel)->bel_data[bel.index].name.get();
if (belname.at(0) == 'D' && using_ce)
continue; // don't allow DCCs with CE at center
@@ -414,7 +414,7 @@ class Ecp5GlobalRouter
}
wirelen_t wirelen = get_dcc_wirelen(dcc, dedicated_routing);
if (wirelen < best_wirelen) {
- if (dedicated_routing) {
+ if (dedicated_routing || dcc->type == id_DCSC) {
best_bel_pclkcib = WireId();
} else {
bool found_pclkcib = false;
@@ -446,11 +446,11 @@ class Ecp5GlobalRouter
}
// Insert a DCC into a net to promote it to a global
- NetInfo *insert_dcc(NetInfo *net)
+ NetInfo *insert_dcc(NetInfo *net, CellInfo *dcs_cell = nullptr)
{
NetInfo *glbptr = nullptr;
CellInfo *dccptr = nullptr;
- if (net->driver.cell != nullptr && net->driver.cell->type == id_DCCA) {
+ if (net->driver.cell != nullptr && (net->driver.cell->type == id_DCCA || net->driver.cell->type == id_DCSC)) {
// Already have a DCC (such as clock gating)
glbptr = net;
dccptr = net->driver.cell;
@@ -463,7 +463,10 @@ class Ecp5GlobalRouter
dcc->ports[id_CLKO].net = glbnet.get();
std::vector<PortRef> keep_users;
for (auto user : net->users) {
- if (user.port == id_CLKFB) {
+ if (dcs_cell != nullptr && user.cell != dcs_cell) {
+ // DCS DCC insertion mode
+ keep_users.push_back(user);
+ } else if (user.port == id_CLKFB) {
keep_users.push_back(user);
} else if (net->driver.cell->type == id_EXTREFB && user.cell->type == id_DCUA) {
keep_users.push_back(user);
@@ -494,7 +497,7 @@ class Ecp5GlobalRouter
}
glbptr->attrs[ctx->id("ECP5_IS_GLOBAL")] = 1;
if (str_or_default(dccptr->attrs, ctx->id("BEL"), "") == "")
- place_dcc(dccptr);
+ place_dcc_dcs(dccptr);
return glbptr;
}
@@ -524,6 +527,20 @@ class Ecp5GlobalRouter
else
insert_dcc(clock);
}
+ // Insert DCCs on DCS inputs, too
+ std::vector<CellInfo *> dcsc_cells;
+ for (auto &cell : ctx->cells) {
+ CellInfo *ci = cell.second.get();
+ if (ci->type == id_DCSC)
+ dcsc_cells.push_back(ci);
+ }
+ for (auto ci : dcsc_cells) {
+ for (auto port : {id_CLK0, id_CLK1}) {
+ NetInfo *net = get_net_or_empty(ci, port);
+ if (net != nullptr)
+ insert_dcc(net, ci);
+ }
+ }
}
void route_globals()
@@ -539,8 +556,8 @@ class Ecp5GlobalRouter
dict<int, NetInfo *> clocks;
for (auto &cell : ctx->cells) {
CellInfo *ci = cell.second.get();
- if (ci->type == id_DCCA) {
- NetInfo *clock = ci->ports.at(id_CLKO).net;
+ if (ci->type == id_DCCA || ci->type == id_DCSC) {
+ NetInfo *clock = ci->ports.at((ci->type == id_DCSC) ? id_DCSOUT : id_CLKO).net;
NPNR_ASSERT(clock != nullptr);
bool drives_fabric = std::any_of(clock->users.begin(), clock->users.end(),
[this](const PortRef &port) { return !is_clock_port(port); });
@@ -571,6 +588,12 @@ class Ecp5GlobalRouter
return global_route_priority(*a.first) < global_route_priority(*b.first);
});
for (const auto &user : toroute) {
+ if (user.first->cell->type == id_DCSC && (user.first->port == id_CLK0 || user.first->port == id_CLK1)) {
+ // Special case, skips most of the typical global network
+ NetInfo *net = clocks.at(user.second);
+ simple_router(net, ctx->getNetinfoSourceWire(net), ctx->getNetinfoSinkWire(net, *(user.first), 0));
+ continue;
+ }
route_logic_tile_global(clocks.at(user.second), user.second, *user.first);
}
}
diff --git a/fpga_interchange/arch.cc b/fpga_interchange/arch.cc
index be40ddfd..901725d4 100644
--- a/fpga_interchange/arch.cc
+++ b/fpga_interchange/arch.cc
@@ -1518,11 +1518,6 @@ void Arch::remove_pip_pseudo_wires(PipId pip, NetInfo *net)
// This wire is part of net->wires, make sure it has no pip,
// but leave it alone. It will get cleaned up via
// unbindWire.
- if (wire_iter->second.pip != PipId() && wire_iter->second.pip != pip) {
- log_error("Wire %s report source'd from pip %s, which is not %s\n", nameOfWire(wire),
- nameOfPip(wire_iter->second.pip), nameOfPip(pip));
- }
- NPNR_ASSERT(wire_iter->second.pip == PipId() || wire_iter->second.pip == pip);
} else {
// This wire is not in net->wires, update wire_to_net.
#ifdef DEBUG_BINDING
@@ -1756,12 +1751,12 @@ bool Arch::checkPipAvailForNet(PipId pip, NetInfo *net) const
NPNR_ASSERT(src != wire);
NPNR_ASSERT(dst != wire);
- NetInfo *net = getConflictingWireNet(wire);
- if (net != nullptr) {
+ NetInfo *other_net = getConflictingWireNet(wire);
+ if (other_net != nullptr && other_net != net) {
#ifdef DEBUG_BINDING
if (getCtx()->verbose) {
log_info("Pip %s is not available because wire %s is tied to net %s\n", getCtx()->nameOfPip(pip),
- getCtx()->nameOfWire(wire), net->name.c_str(getCtx()));
+ getCtx()->nameOfWire(wire), other_net->name.c_str(getCtx()));
}
#endif
return false;
diff --git a/fpga_interchange/arch.h b/fpga_interchange/arch.h
index 6e77054f..896a603a 100644
--- a/fpga_interchange/arch.h
+++ b/fpga_interchange/arch.h
@@ -576,7 +576,8 @@ struct Arch : ArchAPI<ArchRanges>
const PipInfoPOD &pip_data = pip_info(chip_info, pip);
for (int32_t wire_index : pip_data.pseudo_cell_wires) {
wire.index = wire_index;
- assign_net_to_wire(wire, net, "pseudo", /*require_empty=*/true);
+ if (getBoundWireNet(wire) != net)
+ assign_net_to_wire(wire, net, "pseudo", /*require_empty=*/true);
}
if (pip_data.pseudo_cell_wires.size() > 0) {
@@ -708,7 +709,8 @@ struct Arch : ArchAPI<ArchRanges>
// -------------------------------------------------
- void place_iobufs(WireId pad_wire, NetInfo *net, const pool<CellInfo *, hash_ptr_ops> &tightly_attached_bels,
+ void place_iobufs(WireId pad_wire, NetInfo *net,
+ const dict<CellInfo *, IdString, hash_ptr_ops> &tightly_attached_bels,
pool<CellInfo *, hash_ptr_ops> *placed_cells);
void pack_ports();
diff --git a/fpga_interchange/arch_pack_io.cc b/fpga_interchange/arch_pack_io.cc
index 7b8e9f80..19d8cece 100644
--- a/fpga_interchange/arch_pack_io.cc
+++ b/fpga_interchange/arch_pack_io.cc
@@ -27,7 +27,7 @@
NEXTPNR_NAMESPACE_BEGIN
namespace {
-bool search_routing_for_placement(Arch *arch, WireId start_wire, CellInfo *cell, IdString cell_pin)
+bool search_routing_for_placement(Arch *arch, WireId start_wire, CellInfo *cell, IdString cell_pin, bool downhill)
{
std::queue<WireId> visit_queue;
pool<WireId> already_visited;
@@ -51,54 +51,44 @@ bool search_routing_for_placement(Arch *arch, WireId start_wire, CellInfo *cell,
// Bel pin doesn't match
arch->unbindBel(bp.bel);
}
- for (auto pip : arch->getPipsDownhill(next)) {
- WireId dst = arch->getPipDstWire(pip);
+ auto do_visit = [&](PipId pip) {
+ WireId dst = downhill ? arch->getPipDstWire(pip) : arch->getPipSrcWire(pip);
if (already_visited.count(dst))
- continue;
+ return;
if (!arch->is_site_wire(dst) && arch->get_wire_category(dst) == WIRE_CAT_GENERAL)
- continue; // this pass only considers dedicated routing
+ return; // this pass only considers dedicated routing
visit_queue.push(dst);
already_visited.insert(dst);
+ };
+ if (downhill) {
+ for (auto pip : arch->getPipsDownhill(next))
+ do_visit(pip);
+ } else {
+ for (auto pip : arch->getPipsUphill(next))
+ do_visit(pip);
}
}
return false;
}
} // namespace
-void Arch::place_iobufs(WireId pad_wire, NetInfo *net, const pool<CellInfo *, hash_ptr_ops> &tightly_attached_bels,
+void Arch::place_iobufs(WireId pad_wire, NetInfo *net,
+ const dict<CellInfo *, IdString, hash_ptr_ops> &tightly_attached_bels,
pool<CellInfo *, hash_ptr_ops> *placed_cells)
{
- for (BelPin bel_pin : getWireBelPins(pad_wire)) {
- BelId bel = bel_pin.bel;
- for (CellInfo *cell : tightly_attached_bels) {
- if (isValidBelForCellType(cell->type, bel)) {
- NPNR_ASSERT(cell->bel == BelId());
- NPNR_ASSERT(placed_cells->count(cell) == 0);
-
- bindBel(bel, cell, STRENGTH_FIXED);
- placed_cells->emplace(cell);
-
- IdString cell_port;
- for (auto pin_pair : cell->cell_bel_pins) {
- for (IdString a_bel_pin : pin_pair.second) {
- if (a_bel_pin == bel_pin.pin) {
- NPNR_ASSERT(cell_port == IdString());
- cell_port = pin_pair.first;
- }
- }
- }
- NPNR_ASSERT(cell_port != IdString());
-
- const PortInfo &port = cell->ports.at(cell_port);
- NPNR_ASSERT(port.net == net);
- }
+ Context *ctx = getCtx();
+ for (auto cell_port : tightly_attached_bels) {
+ bool downhill = (cell_port.first->ports.at(cell_port.second).type != PORT_OUT);
+ if (search_routing_for_placement(this, pad_wire, cell_port.first, cell_port.second, downhill)) {
+ if (ctx->verbose)
+ log_info("Placed IO cell %s:%s at %s.\n", ctx->nameOf(cell_port.first),
+ ctx->nameOf(cell_port.first->type), ctx->nameOfBel(cell_port.first->bel));
}
}
// Also try, on a best-effort basis, to preplace other cells in the macro based on downstream routing. This is
// needed for the split INBUF+IBUFCTRL arrangement in the UltraScale+, as just placing the INBUF will result in an
// unrouteable site and illegal placement.
- Context *ctx = getCtx();
std::queue<CellInfo *> place_queue;
for (auto pc : *placed_cells)
place_queue.push(pc);
@@ -119,7 +109,7 @@ void Arch::place_iobufs(WireId pad_wire, NetInfo *net, const pool<CellInfo *, ha
if (usr.cell->bel != BelId() || usr.cell->macro_parent != cursor->macro_parent)
continue;
// Try and place using dedicated routing
- if (search_routing_for_placement(this, src_wire, usr.cell, usr.port)) {
+ if (search_routing_for_placement(this, src_wire, usr.cell, usr.port, true)) {
// Successful
placed_cells->insert(usr.cell);
place_queue.push(usr.cell);
@@ -200,34 +190,34 @@ void Arch::pack_ports()
for (auto port_pair : port_cells) {
IdString port_name = port_pair.first;
CellInfo *port_cell = port_pair.second;
- pool<CellInfo *, hash_ptr_ops> tightly_attached_bels;
+ dict<CellInfo *, IdString, hash_ptr_ops> tightly_attached_bels;
for (auto port_pair : port_cell->ports) {
const PortInfo &port_info = port_pair.second;
const NetInfo *net = port_info.net;
if (net->driver.cell) {
- tightly_attached_bels.emplace(net->driver.cell);
+ tightly_attached_bels.emplace(net->driver.cell, net->driver.port);
}
for (const PortRef &port_ref : net->users) {
if (port_ref.cell) {
- tightly_attached_bels.emplace(port_ref.cell);
+ tightly_attached_bels.emplace(port_ref.cell, port_ref.port);
}
}
}
if (getCtx()->verbose) {
log_info("Tightly attached BELs for port %s\n", port_name.c_str(getCtx()));
- for (CellInfo *cell : tightly_attached_bels) {
- log_info(" - %s : %s\n", cell->name.c_str(getCtx()), cell->type.c_str(getCtx()));
+ for (auto cell_port : tightly_attached_bels) {
+ log_info(" - %s : %s\n", cell_port.first->name.c_str(getCtx()), cell_port.first->type.c_str(getCtx()));
}
}
NPNR_ASSERT(tightly_attached_bels.erase(port_cell) == 1);
pool<IdString> cell_types_in_io_group;
- for (CellInfo *cell : tightly_attached_bels) {
- NPNR_ASSERT(port_cells.find(cell->name) == port_cells.end());
- cell_types_in_io_group.emplace(cell->type);
+ for (auto cell_port : tightly_attached_bels) {
+ NPNR_ASSERT(port_cells.find(cell_port.first->name) == port_cells.end());
+ cell_types_in_io_group.emplace(cell_port.first->type);
}
// Get possible placement locations for tightly coupled BELs with
diff --git a/fpga_interchange/examples/tests/CMakeLists.txt b/fpga_interchange/examples/tests/CMakeLists.txt
index 1d3dd72f..f8a52a41 100644
--- a/fpga_interchange/examples/tests/CMakeLists.txt
+++ b/fpga_interchange/examples/tests/CMakeLists.txt
@@ -6,4 +6,5 @@ add_subdirectory(ff)
add_subdirectory(lut)
add_subdirectory(lut_nexus)
add_subdirectory(lutram)
+add_subdirectory(obuftds)
add_subdirectory(ram_nexus)
diff --git a/fpga_interchange/examples/tests/obuftds/CMakeLists.txt b/fpga_interchange/examples/tests/obuftds/CMakeLists.txt
new file mode 100644
index 00000000..0313c9bb
--- /dev/null
+++ b/fpga_interchange/examples/tests/obuftds/CMakeLists.txt
@@ -0,0 +1,7 @@
+add_interchange_group_test(
+ name obuftds
+ family ${family}
+ board_list basys3
+ tcl run.tcl
+ sources obuftds.v
+)
diff --git a/fpga_interchange/examples/tests/obuftds/basys3.xdc b/fpga_interchange/examples/tests/obuftds/basys3.xdc
new file mode 100644
index 00000000..4b777233
--- /dev/null
+++ b/fpga_interchange/examples/tests/obuftds/basys3.xdc
@@ -0,0 +1,9 @@
+set_property PACKAGE_PIN V2 [get_ports sw[8] ]
+set_property PACKAGE_PIN T3 [get_ports sw[9] ]
+set_property PACKAGE_PIN T2 [get_ports sw[10]]
+set_property PACKAGE_PIN R3 [get_ports sw[11]]
+
+set_property PACKAGE_PIN U19 [get_ports diff_p[0]]
+set_property PACKAGE_PIN V19 [get_ports diff_n[0]]
+set_property PACKAGE_PIN V13 [get_ports diff_p[1]]
+set_property PACKAGE_PIN V14 [get_ports diff_n[1]]
diff --git a/fpga_interchange/examples/tests/obuftds/obuftds.v b/fpga_interchange/examples/tests/obuftds/obuftds.v
new file mode 100644
index 00000000..d4e9a603
--- /dev/null
+++ b/fpga_interchange/examples/tests/obuftds/obuftds.v
@@ -0,0 +1,37 @@
+module top(
+ input wire [11:8] sw,
+
+ output wire [1:0] diff_p,
+ output wire [1:0] diff_n
+);
+
+wire [1:0] buf_i;
+wire [1:0] buf_t;
+
+OBUFTDS # (
+ .IOSTANDARD("DIFF_SSTL135"),
+ .SLEW("FAST")
+) obuftds_0 (
+ .I(buf_i[0]),
+ .T(buf_t[0]),
+ .O(diff_p[0]),
+ .OB(diff_n[0])
+);
+
+OBUFTDS # (
+ .IOSTANDARD("DIFF_SSTL135"),
+ .SLEW("FAST")
+) obuftds_1 (
+ .I(buf_i[1]),
+ .T(buf_t[1]),
+ .O(diff_p[1]),
+ .OB(diff_n[1])
+);
+
+assign buf_i[0] = sw[ 8];
+assign buf_t[0] = sw[ 9];
+assign buf_i[1] = sw[10];
+assign buf_t[1] = sw[11];
+
+endmodule
+
diff --git a/fpga_interchange/examples/tests/obuftds/run.tcl b/fpga_interchange/examples/tests/obuftds/run.tcl
new file mode 100644
index 00000000..b8d0df72
--- /dev/null
+++ b/fpga_interchange/examples/tests/obuftds/run.tcl
@@ -0,0 +1,14 @@
+yosys -import
+
+read_verilog $::env(SOURCES)
+
+synth_xilinx -nolutram -nowidelut -nosrl -nocarry -nodsp
+
+# opt_expr -undriven makes sure all nets are driven, if only by the $undef
+# net.
+opt_expr -undriven
+opt_clean
+
+setundef -zero -params
+
+write_json $::env(OUT_JSON)
diff --git a/fpga_interchange/macros.cc b/fpga_interchange/macros.cc
index 42c8e1ba..762615c1 100644
--- a/fpga_interchange/macros.cc
+++ b/fpga_interchange/macros.cc
@@ -58,14 +58,24 @@ void Arch::expand_macros()
std::vector<CellInfo *> next_cells;
+ bool first_iter = false;
do {
// Expand cells
for (auto cell : cells) {
// TODO: consult exception map
const MacroExpansionPOD *exp = lookup_macro_rules(chip_info, cell->type);
+
+ // Block infinite expansion loop due to a macro being expanded in the same primitive.
+ // E.g.: OBUFTDS expands into the following cells, with an infinite loop being generated:
+ // - 2 OBUFTDS
+ // - 1 INV
+ if (exp && first_iter)
+ continue;
+
const MacroPOD *macro = lookup_macro(chip_info, exp ? IdString(exp->macro_name) : cell->type);
if (macro == nullptr)
continue;
+
// Get the ultimate root of this macro expansion
IdString parent = (cell->macro_parent == IdString()) ? cell->name : cell->macro_parent;
// Create child instances
@@ -158,6 +168,8 @@ void Arch::expand_macros()
// The next iteration only needs to look at cells created in this iteration
std::swap(next_cells, cells);
next_cells.clear();
+
+ first_iter = true;
} while (!cells.empty());
// Do this at the end, otherwise we might add cells that are later destroyed
for (auto &cell : ctx->cells)
generated by cgit v1.2.3 (git 2.25.1) at 2025-04-04 10:56:20 +0000