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Eddie Hung 2020-01-02 12:39:52 -08:00
parent 8e507bd807
commit ec1756c094
1 changed files with 6 additions and 11 deletions
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techlibs/xilinx/abc9_map.v
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@ -65,19 +65,14 @@
// the connectivity of its basic D-Q flop
// (b) an optional $__ABC9_ASYNC_ cell in front of $__ABC_FF_'s output to
// capture asynchronous behaviour
// (c) a special _TECHMAP_REPLACE_.abc9_ff.clock wire to capture its clock
// domain and polarity (used when partitioning the module so that `abc9' only
// performs sequential synthesis (with reachability analysis) correctly on
// one domain at a time) and also used to infer the optional delay target
// from the (* abc9_clock_period = %d *) attribute attached to any wire
// within
// (d) a special _TECHMAP_REPLACE_.abc9_ff.init wire to encode the flop's initial
// state
// (c) a special abc9_ff.clock wire to capture its clock domain and polarity
// (indicated to `abc9' so that it only performs sequential synthesis
// (with reachability analysis) correctly on one domain at a time)
// (d) a special abc9_ff.init wire to encode the flop's initial state
// NOTE: in order to perform sequential synthesis, `abc9' also requires
// that the initial value of all flops be zero
// (e) a special _TECHMAP_REPLACE_.abc9_ff.Q wire that will be used for feedback
// into the (combinatorial) FD* cell to facilitate clock-enable behaviour
//
// In order to perform sequential synthesis, `abc9' also requires that
// the initial value of all flops be zero.
module FDRE (output Q, input C, CE, D, R);
parameter [0:0] INIT = 1'b0;