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Add doc

This commit is contained in:
Eddie Hung 2019-08-22 11:52:24 -07:00
parent cabadb85e2
commit 6e8fda8bf0
1 changed files with 14 additions and 1 deletions
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15
passes/pmgen/xilinx_srl.cc
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@ -168,7 +168,20 @@ struct XilinxSrlPass : public Pass {
log("\n");
log(" xilinx_srl [options] [selection]\n");
log("\n");
log("TODO.\n");
log("This pass converts chains of built-in flops ($_DFF_[NP]_, $_DFFE_*) as well as\n");
log("Xilinx flops (FDRE, FDRE_1) into a $__XILINX_SHREG cell. Chains must be of the\n");
log("same type, clock, clock polarity, enable, enable polarity (when relevant).\n");
log("Flops with resets cannot be mapped to Xilinx devices and will not be inferred.");
log("\n");
log(" -minlen N\n");
log(" min length of shift register (default = 3)\n");
log("\n");
log(" -fixed\n");
log(" infer fixed-length shift registers.\n");
log("\n");
log(" -variable\n");
log(" infer variable-length shift registers (i.e. fixed-length shifts where\n");
log(" each element also fans-out to a $shiftx cell.\n");
log("\n");
}