From 71cac30309ec19bb72ff64ae5f5471ba0ecfaf46 Mon Sep 17 00:00:00 2001 From: Eddie Hung Date: Mon, 23 Dec 2019 12:38:18 -0800 Subject: [PATCH] Support unregistered cascades for A and B inputs --- passes/pmgen/xilinx_dsp_cascade.pmg | 121 +++++++++++++++++----------- 1 file changed, 74 insertions(+), 47 deletions(-) diff --git a/passes/pmgen/xilinx_dsp_cascade.pmg b/passes/pmgen/xilinx_dsp_cascade.pmg index 9763facdf..7a310764c 100644 --- a/passes/pmgen/xilinx_dsp_cascade.pmg +++ b/passes/pmgen/xilinx_dsp_cascade.pmg @@ -119,21 +119,42 @@ finally add_siguser(cascade, dsp_pcin); add_siguser(cascade, dsp); - dsp->setParam(ID(ACASCREG), AREG); + if (dsp->type.in(\DSP48E1)) + dsp->setParam(ID(ACASCREG), AREG); dsp_pcin->setParam(ID(A_INPUT), Const("CASCADE")); log_debug("ACOUT -> ACIN cascade for %s -> %s\n", log_id(dsp), log_id(dsp_pcin)); } if (BREG >= 0) { Wire *cascade = module->addWire(NEW_ID, 18); - dsp_pcin->setPort(ID(B), Const(0, 18)); - dsp_pcin->setPort(ID(BCIN), cascade); + if (dsp->type.in(\DSP48A, \DSP48A1)) { + // According to UG389 p9 [https://www.xilinx.com/support/documentation/user_guides/ug389.pdf] + // "The DSP48A1 component uses this input when cascading + // BCOUT from an adjacent DSP48A1 slice. The tools then + // translate BCOUT cascading to the dedicated BCIN input + // and set the B_INPUT attribute for implementation." + dsp_pcin->setPort(ID(B), cascade); + } + else { + dsp_pcin->setPort(ID(B), Const(0, 18)); + dsp_pcin->setPort(ID(BCIN), cascade); + } dsp->setPort(ID(BCOUT), cascade); add_siguser(cascade, dsp_pcin); add_siguser(cascade, dsp); - dsp->setParam(ID(BCASCREG), BREG); - dsp_pcin->setParam(ID(B_INPUT), Const("CASCADE")); + if (dsp->type.in(\DSP48E1)) { + dsp->setParam(ID(BCASCREG), BREG); + // According to UG389 p13 [https://www.xilinx.com/support/documentation/user_guides/ug389.pdf] + // "The attribute is only used by place and route tools and + // is not necessary for the users to set for synthesis. The + // attribute is determined by the connection to the B port + // of the DSP48A1 slice. If the B port is connected to the + // BCOUT of another DSP48A1 slice, then the tools automatically + // set the attribute to 'CASCADE', otherwise it is set to + // 'DIRECT'". + dsp_pcin->setParam(ID(B_INPUT), Const("CASCADE")); + } log_debug("BCOUT -> BCIN cascade for %s -> %s\n", log_id(dsp), log_id(dsp_pcin)); } @@ -202,36 +223,39 @@ code next endcode // (3) For this subequent DSP48E1 match (i.e. PCOUT -> PCIN cascade exists) -// if (a) the previous DSP48E1 uses either the A2REG or A1REG, (b) this -// DSP48 does not use A2REG nor A1REG, (c) this DSP48E1 does not already -// have an ACOUT -> ACIN cascade, (d) the previous DSP does not already -// use its ACOUT port, then examine if an ACOUT -> ACIN cascade -// opportunity exists by matching for a $dff-with-optional-clock-enable- -// or-reset and checking that the 'D' input of this register is the same -// as the 'A' input of the previous DSP +// if (a) this DSP48 does not use A2REG nor A1REG, (b) this DSP48E1 does +// not already have an ACOUT -> ACIN cascade, (c) the previous DSP does +// not already use its ACOUT port, then examine if an ACOUT -> ACIN cascade +// opportunity exists if (i) A ports are identical, or (ii) separated by a +// $dff-with-optional-clock-enable-or-reset and checking that the 'D' input +// of this register is the same as the 'A' input of the previous DSP +// TODO: Check for two levels of flops, instead of just one code argQ clock AREG AREG = -1; - if (next) { + if (next && next->type.in(\DSP48E1)) { Cell *prev = std::get<0>(chain.back()); - if (param(prev, \AREG, 2).as_int() > 0 && - param(next, \AREG, 2).as_int() > 0 && + if (param(next, \AREG, 2).as_int() == 0 && param(next, \A_INPUT, Const("DIRECT")).decode_string() == "DIRECT" && nusers(port(prev, \ACOUT, SigSpec())) <= 1) { - argQ = unextend(port(next, \A)); - clock = port(prev, \CLK); - subpattern(in_dffe); - if (dff) { - if (!dffrstmux && port(prev, \RSTA, State::S0) != State::S0) - goto reject_AREG; - if (dffrstmux && port(dffrstmux, \S) != port(prev, \RSTA, State::S0)) - goto reject_AREG; - if (!dffcemux && port(prev, \CEA2, State::S0) != State::S0) - goto reject_AREG; - if (dffcemux && port(dffcemux, \S) != port(prev, \CEA2, State::S0)) - goto reject_AREG; - if (dffD == unextend(port(prev, \A))) - AREG = 1; -reject_AREG: ; + if (port(prev, \A) == port(next, \A)) + AREG = 0; + else { + argQ = unextend(port(next, \A)); + clock = port(prev, \CLK); + subpattern(in_dffe); + if (dff) { + if (!dffrstmux && port(prev, \RSTA, State::S0) != State::S0) + goto reject_AREG; + if (dffrstmux && port(dffrstmux, \S) != port(prev, \RSTA, State::S0)) + goto reject_AREG; + if (!dffcemux && port(prev, \CEA2, State::S0) != State::S0) + goto reject_AREG; + if (dffcemux && port(dffcemux, \S) != port(prev, \CEA2, State::S0)) + goto reject_AREG; + if (dffD == unextend(port(prev, \A))) + AREG = 1; +reject_AREG: ; + } } } } @@ -242,26 +266,29 @@ code argQ clock BREG BREG = -1; if (next) { Cell *prev = std::get<0>(chain.back()); - if (param(prev, \BREG, 2).as_int() > 0 && - param(next, \BREG, 2).as_int() > 0 && + if (((next->type.in(\DSP48A, \DSP48A1) && param(next, \B1REG, 1) == 0) || (next->type.in(\DSP48E1) && param(next, \BREG, 2).as_int() == 0)) && param(next, \B_INPUT, Const("DIRECT")).decode_string() == "DIRECT" && port(next, \BCIN, SigSpec()).is_fully_zero() && nusers(port(prev, \BCOUT, SigSpec())) <= 1) { - argQ = unextend(port(next, \B)); - clock = port(prev, \CLK); - subpattern(in_dffe); - if (dff) { - if (!dffrstmux && port(prev, \RSTB, State::S0) != State::S0) - goto reject_BREG; - if (dffrstmux && port(dffrstmux, \S) != port(prev, \RSTB, State::S0)) - goto reject_BREG; - if (!dffcemux && port(prev, \CEB2, State::S0) != State::S0) - goto reject_BREG; - if (dffcemux && port(dffcemux, \S) != port(prev, \CEB2, State::S0)) - goto reject_BREG; - if (dffD == unextend(port(prev, \B))) - BREG = 1; -reject_BREG: ; + if (port(prev, \B) == port(next, \B)) + BREG = 0; + else { + argQ = unextend(port(next, \B)); + clock = port(prev, \CLK); + subpattern(in_dffe); + if (dff) { + if (!dffrstmux && port(prev, \RSTB, State::S0) != State::S0) + goto reject_BREG; + if (dffrstmux && port(dffrstmux, \S) != port(prev, \RSTB, State::S0)) + goto reject_BREG; + if (!dffcemux && port(prev, \CEB2, State::S0) != State::S0) + goto reject_BREG; + if (dffcemux && port(dffcemux, \S) != port(prev, \CEB2, State::S0)) + goto reject_BREG; + if (dffD == unextend(port(prev, \B))) + BREG = 1; +reject_BREG: ; + } } } } -- 2.30.2