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author | Eddie Hung <eddie@fpgeh.com> | 2020-01-02 12:39:52 -0800 |
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committer | Eddie Hung <eddie@fpgeh.com> | 2020-01-02 12:39:52 -0800 |
commit | ec1756c0941fac02614c25307b17bb41fe36f468 (patch) | |
tree | 35c19b2ce32ed2632ff53fde17b30ce0b1216c92 /techlibs/xilinx/abc9_map.v | |
parent | 8e507bd80785db9fa6723eada4214a5a06516cae (diff) | |
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Diffstat (limited to 'techlibs/xilinx/abc9_map.v')
-rw-r--r-- | techlibs/xilinx/abc9_map.v | 17 |
1 files changed, 6 insertions, 11 deletions
diff --git a/techlibs/xilinx/abc9_map.v b/techlibs/xilinx/abc9_map.v index 1d37952f5..af58e217c 100644 --- a/techlibs/xilinx/abc9_map.v +++ b/techlibs/xilinx/abc9_map.v @@ -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; |