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Diffstat (limited to 'docs')
| -rw-r--r-- | docs/archapi.md | 43 |
1 files changed, 39 insertions, 4 deletions
diff --git a/docs/archapi.md b/docs/archapi.md index a9c38589..481448e3 100644 --- a/docs/archapi.md +++ b/docs/archapi.md @@ -377,7 +377,7 @@ the given dst wire. This should return a low upper bound for the fastest route from `src` to `dst`. Or in other words it should assume an otherwise unused chip (thus "fastest route"). -But it only produces an estimate for that fastest route, not an exact +But it only produces an estimate for that fastest route, not an exact result, and for that estimate it is considered more acceptable to return a slightly too high result and it is considered less acceptable to return a too low result (thus "low upper bound"). @@ -463,21 +463,57 @@ Cell Delay Methods Returns the delay for the specified path through a cell in the `&delay` argument. The method returns false if there is no timing relationship from `fromPort` to `toPort`. -### TimingPortClass getPortTimingClass(const CellInfo *cell, IdString port, int &clockInfoCount) const +### TimingPortClass getPortTimingClass(const CellInfo \*cell, IdString port, int &clockInfoCount) const Return the _timing port class_ of a port. This can be a register or combinational input or output; clock input or output; general startpoint or endpoint; or a port ignored for timing purposes. For register ports, clockInfoCount is set to the number of associated _clock edges_ that can be queried by getPortClockingInfo. -### TimingClockingInfo getPortClockingInfo(const CellInfo *cell, IdString port, int index) const +### TimingClockingInfo getPortClockingInfo(const CellInfo \*cell, IdString port, int index) const Return the _clocking info_ (including port name of clock, clock polarity and setup/hold/clock-to-out times) of a port. Where ports have more than one clock edge associated with them (such as DDR outputs), `index` can be used to obtain information for all edges. `index` must be in [0, clockInfoCount), behaviour is undefined otherwise. +Partition Methods +----------------- + +Partitions are used by analytic placement to seperate types of BELs during +placement. Typical partitions are: + - All LUT BELs + - All FF BELs + - All multipliers BELs + - All block RAM BELs + - etc. + +The general rule here is to include all BELs that are roughly interchangable +during placement. + +### const\_range\<PartitionId\> getPartitions() const + +Return a list of all partitions on the device. + +### IdString partitionName(PartitionId partition) const + +Return the name of the partition. + +### PartitionId partitionForBel(BelId bel) const + +Returns the partition for a particular cell type. + +### const\_range\<BelId\> partitionForBel(PartitionId partition) const + +Return the list of BELs within a partition. + Placer Methods -------------- +### bool isValidBelForCellType(IdString cell\_type, BelId bel) const + +Returns true if the given cell can be bound to the given BEL. This check +should be fast, compared with isValidBelForCell. This check should always +return the same value regardless if other cells are placed within the fabric. + ### bool isValidBelForCell(CellInfo \*cell, BelId bel) const Returns true if the given cell can be bound to the given bel, considering @@ -489,7 +525,6 @@ a certain number of different clock signals allowed for a group of bels. Returns true if a bell in the current configuration is valid, i.e. if `isValidBelForCell()` would return true for the current mapping. - ### static const std::string defaultPlacer Name of the default placement algorithm for the architecture, if |