z2006.12  Synopsys Inc. 1988-2006. All rights reserved.       2-1






all_fanout(2)                                   Synopsys Commands



_N_A_M_E
          all_fanout     Creates a collection of pins/ports or
                         cells in the fanout of the specified
                         sources.


SYNTAX
          collection all_fanout -from _s_o_u_r_c_e__l_i_s_t
                 -clock_tree [-flat]
                 [-only_cells] [-endpoints_only]
                 [-levels level_count]
                 [-pin_levels pin_count]
                 [-step_into_hierarchy]

         list _s_o_u_r_c_e__l_i_s_t
         int  _l_e_v_e_l__c_o_u_n_t


ARGUMENTS
          -from _s_o_u_r_c_e__l_i_s_t
                         Specifies a list of source pins, ports,
                         or nets in the design. Each object is a
                         named pin, port, or net, or a collection
                         of pins, ports, or nets.  The timing
                         fanout of each source in _s_o_u_r_c_e__l_i_s_t
                         becomes part of the resulting
                         collection.  If a net is specified, the
                         effect is the same as listing all load
                         pins on the net.  This option is
                         exclusive with the -clock_tree option.


          -clock_tree    Indicates that all clock source pins
                         and/or ports in the design are to be
                         used as the list of sources.  Clock
                         sources are specified using
                         create_clock.  If there are no clocks,
                         or if the clocks have no sources, the
                         result is the empty collection.  This
                         option is exclusive with the -from
                         option.


          -endpoints_only
                         When this option is specified, only the
                         timing endpoints will be included in the
                         result.


          -only_cells    The result will include only cells in
                         the timing fanout of the _s_o_u_r_c_e__l_i_s_t and
                         not pins or ports.



2-2       Synopsys Inc. 1988-2006. All rights reserved.  z2006.12






Synopsys Commands                                    all_fanout(2)



          -flat          There are two major modes in which
                         all_fanout functions:  hierarchical (the
                         default) and flat.  When in hierarchical
                         mode, only objects within the same
                         hierarchical level as the current source
                         are included in the result. In flat
                         mode, the only non-leaf objects in the
                         result will be hierarchical source pins.


          -levels _c_e_l_l__c_o_u_n_t
                         The traversal will stop when reaching a
                         depth of search of _c_e_l_l__c_o_u_n_t hops,
                         where the counting is performed over the
                         layers of cells of same distance from
                         the source.


          -pin_levels _p_i_n__c_o_u_n_t
                         The traversal will stop when reaching a
                         depth of search of _p_i_n__c_o_u_n_t hops, where
                         the counting is performed over the
                         layers of pins of same distance from the
                         source.


          -step_into_hierarchy
                         This option may only be used in
                         hierarchical mode and only has effect
                         with either -levels or -pin_levels.
                         Without the switch, a hierarchical block
                         at the same level of hierarchy as the
                         current sink is considered to be a cell;
                         the output pins are considered a single
                         level away from the related input pins,
                         regardless of what is inside the block.
                         With the switch enabled, the counting is
                         performed as though the design were
                         flat, and although pins inside the
                         hierarchy are not returned, they
                         determine the depth of the related input
                         pins.


DESCRIPTION
          The all_fanout command creates a collection of objects
          in the timing fanout  of specified source pins/ports or
          nets in the design.  A pin is considered to be in the
          timing fanout of a source if there is a timing path
          through combinational logic from that source to the
          pin.  The fanout stops at the inputs to registers
          (sequential cells).  The sources are specified using



z2006.12  Synopsys Inc. 1988-2006. All rights reserved.       2-3






all_fanout(2)                                   Synopsys Commands



          either -clock_tree or -from _s_o_u_r_c_e__l_i_s_t.

          If current instance in the design is not the top level
          of hierarchy, only objects within the current instance
          will be returned.


EXAMPLES
          This example shows the timing fanout of a port in the
          design. The fanout includes a register, reg3.

               pt_shell> query_objects [all_fanout -from in1]
               {"in1", "reg3/D"}



          This example shows the difference between the
          hierarhical and flat modes of all_fanout.  The source
          is an output pin of a hierarchical cell, H3/z1, which
          is connected to an input pin of another hierarchical
          cell, H4/a.  H4 contains contains a leaf cell U1 with
          input A and output Z.  The first command is
          hierarchical mode, and shows that hierarchical pins are
          included in the result.  The second command is in leaf
          mode, and leaf pins from the lower level are included.

               pt_shell> query_objects [all_fanout -from H3/z1]
               {"H3/z1", "H4/a", "H4/z", "reg2/D"}

               pt_shell> query_objects [all_fanout -from H3/z1 -flat]
               {"H3/z1", "H4/U1/A", "H4/U1/Z", "reg2/D"}



SEE ALSO
          all_fanin(2), _r_e_p_o_r_t__t_r_a_n_s_i_t_i_v_e__f_a_n_i_n(2),
          _c_u_r_r_e_n_t__i_n_s_t_a_n_c_e(2).


















2-4       Synopsys Inc. 1988-2006. All rights reserved.  z2006.12