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Merge remote-tracking branch 'origin/master' into xaig_arrival

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Eddie Hung 2019-08-30 12:28:35 -07:00
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@ -347,6 +347,20 @@ Verilog Attributes and non-standard features
it as the external-facing pin of an I/O pad, and prevents ``iopadmap``
from inserting another pad cell on it.
- The module attribute ``abc_box_id`` specifies a positive integer linking a
blackbox or whitebox definition to a corresponding entry in a `abc9`
box-file.
- The port attribute ``abc_carry`` marks the carry-in (if an input port) and
carry-out (if output port) ports of a box. This information is necessary for
`abc9` to preserve the integrity of carry-chains. Specifying this attribute
onto a bus port will affect only its most significant bit.
- The port attribute ``abc_arrival`` specifies an integer (for output ports
only) to be used as the arrival time of this sequential port. It can be used,
for example, to specify the clk-to-Q delay of a flip-flop for consideration
during techmapping.
- In addition to the ``(* ... *)`` attribute syntax, Yosys supports
the non-standard ``{* ... *}`` attribute syntax to set default attributes
for everything that comes after the ``{* ... *}`` statement. (Reset
@ -423,20 +437,6 @@ Verilog Attributes and non-standard features
blackboxes and whiteboxes. Use ``read_verilog -specify`` to enable this
functionality. (By default specify .. endspecify blocks are ignored.)
- The module attribute ``abc_box_id`` specifies a positive integer linking a
blackbox or whitebox definition to a corresponding entry in a `abc9`
box-file.
- The port attribute ``abc_carry`` marks the carry-in (if an input port) and
carry-out (if output port) ports of a box. This information is necessary for
`abc9` to preserve the integrity of carry-chains. Specifying this attribute
onto a bus port will affect only its most significant bit.
- The port attribute ``abc_arrival`` specifies an integer (for output ports
only) to be used as the arrival time of this sequential port. It can be used,
for example, to specify the clk-to-Q delay of a flip-flop for consideration
during techmapping.
Non-standard or SystemVerilog features for formal verification
==============================================================