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Merge pull request #764 from acomodi/fix-pseudo-pips

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interchange: disallow pseudo-pip on same nets if tile has luts
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gatecat 2021-07-15 17:39:13 +01:00 committed by GitHub
commit 2c4599612c
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1 changed files with 18 additions and 8 deletions
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24
fpga_interchange/arch.cc
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@ -1741,8 +1741,12 @@ bool Arch::checkPipAvailForNet(PipId pip, NetInfo *net) const
} }
} }
// If this pip is a route-though, make sure all of the route-though // If this pip is a route-though, make sure all of the route-though are valid.
// wires are unbound. // A route-through is valid if:
// - none of the pseudo-pip wires are bound to a net
// - the pseudo pip wires are bound to the same net and there are no
// lut elements in the tile type: this to prevent the router from choosing
// a pseudo-pip on the same LUT and on a different input pin for the same net.
const TileTypeInfoPOD &tile_type = loc_info(chip_info, pip); const TileTypeInfoPOD &tile_type = loc_info(chip_info, pip);
const PipInfoPOD &pip_data = tile_type.pip_data[pip.index]; const PipInfoPOD &pip_data = tile_type.pip_data[pip.index];
WireId wire; WireId wire;
@ -1753,16 +1757,22 @@ bool Arch::checkPipAvailForNet(PipId pip, NetInfo *net) const
NPNR_ASSERT(dst != wire); NPNR_ASSERT(dst != wire);
NetInfo *other_net = getConflictingWireNet(wire); NetInfo *other_net = getConflictingWireNet(wire);
if (other_net != nullptr && other_net != net) { bool is_null_net = other_net == nullptr;
if (!is_null_net) {
bool is_same_net = other_net == net;
bool tile_has_luts = tile_type.lut_elements.size() > 0;
if (!is_same_net || tile_has_luts) {
#ifdef DEBUG_BINDING #ifdef DEBUG_BINDING
if (getCtx()->verbose) { if (getCtx()->verbose)
log_info("Pip %s is not available because wire %s is tied to net %s\n", getCtx()->nameOfPip(pip), log_info("Pip %s is not available because wire %s is tied to a different net "
getCtx()->nameOfWire(wire), other_net->name.c_str(getCtx())); "(other net: %s - orig net: %s) or the pseudo pip may traverses LUTs\n",
} getCtx()->nameOfPip(pip), getCtx()->nameOfWire(wire), other_net->name.c_str(getCtx()),
net == nullptr ? "NULL net" : net->name.c_str(getCtx()));
#endif #endif
return false; return false;
} }
} }
}
auto tile_status_iter = tileStatus.find(pip.tile); auto tile_status_iter = tileStatus.find(pip.tile);