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clarification of AddressRange arguments

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Howard Mao
2019-09-08 16:19:21 -07:00
parent 334e443003
commit e9bce0fc3d
1 changed files with 13 additions and 9 deletions
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22
docs/TileLink-Diplomacy-Reference/NodeTypes.rst
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@@ -29,7 +29,7 @@ object from testchipip like so:
name = "my-client",
sourceId = IdRange(0, 4),
requestFifo = true,
visibility = Seq(AddressSet(0, 0xffff))))
visibility = Seq(AddressSet(0x10000, 0xffff))))
lazy val module = new LazyModuleImp(this) {
val (tl, edge) = node.out(0)
@@ -53,13 +53,13 @@ If it is set to true, the client will request that downstream managers that
support it send responses in FIFO order (that is, in the same order the
corresponding requests were sent).
The ``visibility`` argument specifies the address ranges that the client
will access. By default it is set to include all addresses. In this example,
we set it to contain a single address range ``AddressSet(0, 0xffff)``, which
means that the client will only access addresses in this range. Clients
normally do not specify this, but it can help downstream crossbar generators
optimize the hardware by not arbitrating the client to managers with address
ranges that don't overlap with its visibility.
The ``visibility`` argument specifies the address ranges that the client will
access. By default it is set to include all addresses. In this example, we set
it to contain a single address range ``AddressSet(0x10000, 0xffff)``, which
means that the client will only be able to access addresses from 0x10000 to
0x1ffff. normally do not specify this, but it can help downstream crossbar
generators optimize the hardware by not arbitrating the client to managers with
address ranges that don't overlap with its visibility.
Inside your lazy module implementation, you can call ``node.out`` to get a
list of bundle/edge pairs. If you used the TLHelper, you only specified a
@@ -116,7 +116,11 @@ is a TLManagerParameters object.
The only required argument for ``TLManagerParameters`` is the ``address``,
which is the set of address ranges that this manager will serve.
This information is used to route requests from the clients.
This information is used to route requests from the clients. In this example,
the manager will only take requests for addresses from 0x20000 to 0x20fff.
The second argument in ``AddressSet`` is a mask, not a size.
You should generally set it to be one less than a power of two. Otherwise,
the addressing behavior may not be what you expect.
The second argument is ``resources``, which is usually retrieved from a
``Device`` object. In this case, we use a ``SimpleDevice`` object.