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| author | Eddie Hung <eddie@fpgeh.com> | 2019-10-04 22:24:15 -0700 | 
|---|---|---|
| committer | Eddie Hung <eddie@fpgeh.com> | 2019-10-04 22:31:04 -0700 | 
| commit | 12fd2ec4f05ce5efda2a2d2e4d37aef013f2baf9 (patch) | |
| tree | 8e8058f740e9e0233065ae41a6285e1ed537430a /passes/pmgen | |
| parent | 14e4aeece6adc0808ab1876f01752acb0833185a (diff) | |
| download | yosys-12fd2ec4f05ce5efda2a2d2e4d37aef013f2baf9.tar.gz yosys-12fd2ec4f05ce5efda2a2d2e4d37aef013f2baf9.tar.bz2 yosys-12fd2ec4f05ce5efda2a2d2e4d37aef013f2baf9.zip  | |
Improve comments for xilinx_dsp_CREG
Diffstat (limited to 'passes/pmgen')
| -rw-r--r-- | passes/pmgen/xilinx_dsp_CREG.pmg | 13 | 
1 files changed, 7 insertions, 6 deletions
diff --git a/passes/pmgen/xilinx_dsp_CREG.pmg b/passes/pmgen/xilinx_dsp_CREG.pmg index 3d911b478..3f8486406 100644 --- a/passes/pmgen/xilinx_dsp_CREG.pmg +++ b/passes/pmgen/xilinx_dsp_CREG.pmg @@ -7,11 +7,12 @@  //       (attached to at most two $mux cells that implement clock-enable or  //        reset functionality, using a subpattern discussed below)  // Notes: -//   - Separating out CREG packing is necessary since there is no guarantee -//     that the cell ordering corresponds to the "expected" case (i.e. the order -//     in which they appear in the source) thus the possiblity existed that a -//     register got packed as a CREG into a downstream DSP that should have -//     otherwise been a PREG of an upstream DSP that had not been visited yet +//   - Running CREG packing after xilinx_dsp_pack is necessary since there is no +//     guarantee that the cell ordering corresponds to the "expected" case (i.e. +//     the order in which they appear in the source) thus the possiblity existed +//     that a register got packed as a CREG into a downstream DSP that should +//     have otherwise been a PREG of an upstream DSP that had not been visited +//     yet  //   - The reason this is separated out from the xilinx_dsp.pmg file is  //     for efficiency --- each *.pmg file creates a class of the same basename,  //     which when constructed, creates a custom database tailored to the @@ -28,7 +29,7 @@ state <SigSpec> sigC sigP  state <bool> ffCcepol ffCrstpol  state <Cell*> ffC ffCcemux ffCrstmux -// subpattern +// Variables used for subpatterns  state <SigSpec> argQ argD  state <bool> ffcepol ffrstpol  state <int> ffoffset  | 
