From b2b5cf78e21def63c54c080217d77afefba8e4c7 Mon Sep 17 00:00:00 2001 From: Eddie Hung Date: Wed, 26 Jun 2019 13:50:19 -0700 Subject: [PATCH] Rework muxcover decoder gen if more significant muxes are 1'bx --- passes/techmap/muxcover.cc | 94 ++++++++++++++++++++++---------------- 1 file changed, 55 insertions(+), 39 deletions(-) diff --git a/passes/techmap/muxcover.cc b/passes/techmap/muxcover.cc index b0722134e..0f86aeff0 100644 --- a/passes/techmap/muxcover.cc +++ b/passes/techmap/muxcover.cc @@ -324,13 +324,7 @@ struct MuxcoverWorker ok = ok && follow_muxtree(G, tree, bit, "BBA"); ok = ok && follow_muxtree(H, tree, bit, "BBB"); - ok = ok && follow_muxtree(S1, tree, bit, "AAS"); - ok = ok && follow_muxtree(S2, tree, bit, "ABS"); - ok = ok && follow_muxtree(S3, tree, bit, "BAS"); - ok = ok && follow_muxtree(S4, tree, bit, "BBS"); - - if (nodecode) - ok = ok && S1 == S2 && S2 == S3 && S3 == S4; + ok = ok && follow_muxtree(U1, tree, bit, "S"); ok = ok && follow_muxtree(T1, tree, bit, "AS"); ok = ok && follow_muxtree(T2, tree, bit, "BS"); @@ -338,7 +332,14 @@ struct MuxcoverWorker if (nodecode) ok = ok && T1 == T2; - ok = ok && follow_muxtree(U1, tree, bit, "S"); + ok = ok && follow_muxtree(S1, tree, bit, "AAS"); + ok = ok && follow_muxtree(S2, tree, bit, "ABS"); + ok = ok && follow_muxtree(S3, tree, bit, "BAS"); + ok = ok && follow_muxtree(S4, tree, bit, "BBS"); + + if (nodecode) + ok = ok && S1 == S2 && /*S2 == S3 &&*/ S3 == S4; + // ^^ Should already be checked by T1 == T2 above if (ok) { @@ -353,12 +354,16 @@ struct MuxcoverWorker mux.inputs.push_back(G); mux.inputs.push_back(H); - mux.cost += prepare_decode_mux(S1, S2, T1, bit); - mux.cost += prepare_decode_mux(S3, S4, T2, bit); - mux.cost += prepare_decode_mux(S1, S3, U1, bit); - mux.cost += prepare_decode_mux(T1, T2, U1, bit); + if (T1 != RTLIL::Sx) { + mux.cost += prepare_decode_mux(S1, S2, T1, bit); + mux.cost += prepare_decode_mux(S3, S4, T2, bit); + mux.cost += prepare_decode_mux(S1, S3, U1, bit); + } + else + S1 = RTLIL::Sx; + mux.selects.push_back(S1); mux.selects.push_back(T1); mux.selects.push_back(U1); @@ -397,17 +402,13 @@ struct MuxcoverWorker ok = ok && follow_muxtree(O, tree, bit, "BBBA"); ok = ok && follow_muxtree(P, tree, bit, "BBBB"); - ok = ok && follow_muxtree(S1, tree, bit, "AAAS"); - ok = ok && follow_muxtree(S2, tree, bit, "AABS"); - ok = ok && follow_muxtree(S3, tree, bit, "ABAS"); - ok = ok && follow_muxtree(S4, tree, bit, "ABBS"); - ok = ok && follow_muxtree(S5, tree, bit, "BAAS"); - ok = ok && follow_muxtree(S6, tree, bit, "BABS"); - ok = ok && follow_muxtree(S7, tree, bit, "BBAS"); - ok = ok && follow_muxtree(S8, tree, bit, "BBBS"); + ok = ok && follow_muxtree(V1, tree, bit, "S"); + + ok = ok && follow_muxtree(U1, tree, bit, "AS"); + ok = ok && follow_muxtree(U2, tree, bit, "BS"); if (nodecode) - ok = ok && S1 == S2 && S2 == S3 && S3 == S4 && S4 == S5 && S5 == S6 && S6 == S7 && S7 == S8; + ok = ok && U1 == U2; ok = ok && follow_muxtree(T1, tree, bit, "AAS"); ok = ok && follow_muxtree(T2, tree, bit, "ABS"); @@ -415,15 +416,20 @@ struct MuxcoverWorker ok = ok && follow_muxtree(T4, tree, bit, "BBS"); if (nodecode) - ok = ok && T1 == T2 && T2 == T3 && T3 == T4; + ok = ok && T1 == T2 && /*T2 == T3 &&*/ T3 == T4; + // ^^ Should already be checked by U1 == U2 above - ok = ok && follow_muxtree(U1, tree, bit, "AS"); - ok = ok && follow_muxtree(U2, tree, bit, "BS"); + ok = ok && follow_muxtree(S1, tree, bit, "AAAS"); + ok = ok && follow_muxtree(S2, tree, bit, "AABS"); + ok = ok && follow_muxtree(S3, tree, bit, "ABAS"); + ok = ok && follow_muxtree(S4, tree, bit, "ABBS"); + ok = ok && follow_muxtree(S5, tree, bit, "BAAS"); + ok = ok && follow_muxtree(S6, tree, bit, "BABS"); + ok = ok && follow_muxtree(S7, tree, bit, "BBAS"); + ok = ok && follow_muxtree(S8, tree, bit, "BBBS"); if (nodecode) - ok = ok && U1 == U2; - - ok = ok && follow_muxtree(V1, tree, bit, "S"); + ok = ok && S1 == S2 && /*S2 == S3 &&*/ S3 == S4 && /*S4 == S5 &&*/ S5 == S6 && /*S6 == S7 &&*/ S7 == S8; if (ok) { @@ -446,20 +452,30 @@ struct MuxcoverWorker mux.inputs.push_back(O); mux.inputs.push_back(P); - mux.cost += prepare_decode_mux(S1, S2, T1, bit); - mux.cost += prepare_decode_mux(S3, S4, T2, bit); - mux.cost += prepare_decode_mux(S5, S6, T3, bit); - mux.cost += prepare_decode_mux(S7, S8, T4, bit); - mux.cost += prepare_decode_mux(S1, S3, U1, bit); - mux.cost += prepare_decode_mux(S5, S7, U2, bit); - mux.cost += prepare_decode_mux(S1, S5, V1, bit); - - mux.cost += prepare_decode_mux(T1, T2, U1, bit); - mux.cost += prepare_decode_mux(T3, T4, U2, bit); - mux.cost += prepare_decode_mux(T1, T3, V1, bit); - mux.cost += prepare_decode_mux(U1, U2, V1, bit); + if (U1 != RTLIL::Sx) { + mux.cost += prepare_decode_mux(T1, T2, U1, bit); + mux.cost += prepare_decode_mux(T3, T4, U2, bit); + mux.cost += prepare_decode_mux(T1, T3, V1, bit); + + if (T1 != RTLIL::Sx) { + mux.cost += prepare_decode_mux(S1, S2, T1, bit); + mux.cost += prepare_decode_mux(S3, S4, T2, bit); + mux.cost += prepare_decode_mux(S5, S6, T3, bit); + mux.cost += prepare_decode_mux(S7, S8, T4, bit); + mux.cost += prepare_decode_mux(S1, S3, U1, bit); + mux.cost += prepare_decode_mux(S5, S7, U2, bit); + mux.cost += prepare_decode_mux(S1, S5, V1, bit); + } + else + S1 = RTLIL::Sx; + } + else { + T1 = RTLIL::Sx; + S1 = RTLIL::Sx; + } + mux.selects.push_back(S1); mux.selects.push_back(T1); mux.selects.push_back(U1); -- 2.30.2