From aff6ad1ce09264fb7fbf43a7456a746a586bea90 Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Marcin=20Ko=C5=9Bcielnicki?= Date: Thu, 21 Nov 2019 06:30:06 +0100 Subject: xilinx: Improve flip-flop handling. This adds support for infering more kinds of flip-flops: - FFs with async set/reset and clock enable - FFs with sync set/reset - FFs with sync set/reset and clock enable Some passes have been moved (and some added) in order for dff2dffs to work correctly. This gives us complete coverage of Virtex 6+ and Spartan 6 flip-flop capabilities (though not latch capabilities). Older FPGAs also support having both a set and a reset input, which will be handled at a later data. --- techlibs/xilinx/synth_xilinx.cc | 15 +++++++++++---- 1 file changed, 11 insertions(+), 4 deletions(-) (limited to 'techlibs/xilinx/synth_xilinx.cc') diff --git a/techlibs/xilinx/synth_xilinx.cc b/techlibs/xilinx/synth_xilinx.cc index 2c5686a35..a061c8dc0 100644 --- a/techlibs/xilinx/synth_xilinx.cc +++ b/techlibs/xilinx/synth_xilinx.cc @@ -444,6 +444,16 @@ struct SynthXilinxPass : public ScriptPass } if (check_label("map_ffram")) { + // Required for dffsr2dff to work. + run("simplemap t:$dff t:$adff t:$mux"); + // Needs to be done before opt -mux_bool happens. + run("dffsr2dff"); + if (help_mode) + run("dff2dffs [-match-init]", "(-match-init for xc6s only)"); + else if (family == "xc6s") + run("dff2dffs -match-init"); + else + run("dff2dffs"); if (widemux > 0) run("opt -fast -mux_bool -undriven -fine"); // Necessary to omit -mux_undef otherwise muxcover // performs less efficiently @@ -453,14 +463,11 @@ struct SynthXilinxPass : public ScriptPass } if (check_label("fine")) { - run("dffsr2dff"); - run("dff2dffe"); + run("dff2dffe -direct-match $_DFF_* -direct-match $__DFFS_*"); if (help_mode) { - run("simplemap t:$mux", " ('-widemux' only)"); run("muxcover , ('-widemux' only)"); } else if (widemux > 0) { - run("simplemap t:$mux"); constexpr int cost_mux2 = 100; std::string muxcover_args = stringf(" -nodecode -mux2=%d", cost_mux2); switch (widemux) { -- cgit v1.2.3