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Merge pull request #1656 from YosysHQ/eddie/ice40_abc9_warnings

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ice40: reduce ABC9 internal fanout warnings with a param for CI->I3
This commit is contained in:
Eddie Hung 2020-01-27 09:54:04 -08:00 • committed by GitHub
commit af8281d2f5
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6 changed files with 26 additions and 32 deletions
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15
passes/pmgen/ice40_wrapcarry.cc
View file

@ -42,11 +42,19 @@ void create_ice40_wrapcarry(ice40_wrapcarry_pm &pm)
cell->setPort("\\A", st.carry->getPort("\\I0"));
cell->setPort("\\B", st.carry->getPort("\\I1"));
cell->setPort("\\CI", st.carry->getPort("\\CI"));
auto CI = st.carry->getPort("\\CI");
cell->setPort("\\CI", CI);
cell->setPort("\\CO", st.carry->getPort("\\CO"));
cell->setPort("\\I0", st.lut->getPort("\\I0"));
cell->setPort("\\I3", st.lut->getPort("\\I3"));
auto I3 = st.lut->getPort("\\I3");
if (pm.sigmap(CI) == pm.sigmap(I3)) {
cell->setParam("\\I3_IS_CI", State::S1);
I3 = State::Sx;
}
else
cell->setParam("\\I3_IS_CI", State::S0);
cell->setPort("\\I3", I3);
cell->setPort("\\O", st.lut->getPort("\\O"));
cell->setParam("\\LUT", st.lut->getParam("\\LUT_INIT"));
@ -118,7 +126,8 @@ struct Ice40WrapCarryPass : public Pass {
auto lut = module->addCell(lut_name, ID($lut));
lut->setParam(ID(WIDTH), 4);
lut->setParam(ID(LUT), cell->getParam(ID(LUT)));
lut->setPort(ID(A), {cell->getPort(ID(I0)), cell->getPort(ID(A)), cell->getPort(ID(B)), cell->getPort(ID(I3)) });
auto I3 = cell->getPort(cell->getParam(ID(I3_IS_CI)).as_bool() ? ID(CI) : ID(I3));
lut->setPort(ID(A), {cell->getPort(ID(I0)), cell->getPort(ID(A)), cell->getPort(ID(B)), I3 });
lut->setPort(ID(Y), cell->getPort(ID(O)));
Const src;

4
techlibs/ice40/abc9_model.v
View file

@ -9,6 +9,8 @@ module \$__ICE40_CARRY_WRAPPER (
input I0, I3
);
parameter LUT = 0;
parameter I3_IS_CI = 0;
wire I3_OR_CI = I3_IS_CI ? CI : I3;
SB_CARRY carry (
.I0(A),
.I1(B),
@ -21,7 +23,7 @@ module \$__ICE40_CARRY_WRAPPER (
.I0(I0),
.I1(A),
.I2(B),
.I3(I3),
.I3(I3_OR_CI),
.O(O)
);
endmodule

3
techlibs/ice40/abc9_u.box
View file

@ -6,13 +6,12 @@
# Box 1 : $__ICE40_CARRY_WRAPPER (private cell used to preserve
# SB_LUT4+SB_CARRY)
# Outputs: O, CO
# (Exception: carry chain input/output must be the
# last input and output and the entire bus has been
# moved there overriding the otherwise
# alphabetical ordering)
# name ID w/b ins outs
$__ICE40_CARRY_WRAPPER 1 1 5 2
#A B I0 I3 CI
#A B I0 I3 CI
1231 1205 1285 874 874 # O
675 609 - - 278 # CO

5
techlibs/ice40/arith_map.v
View file

@ -49,13 +49,14 @@ module _80_ice40_alu (A, B, CI, BI, X, Y, CO);
// A[1]: 1100 1100 1100 1100
// A[2]: 1111 0000 1111 0000
// A[3]: 1111 1111 0000 0000
.LUT(16'b 0110_1001_1001_0110)
.LUT(16'b 0110_1001_1001_0110),
.I3_IS_CI(1'b1)
) carry (
.A(AA[i]),
.B(BB[i]),
.CI(C[i]),
.I0(1'b0),
.I3(C[i]),
.I3(1'bx),
.CO(CO[i]),
.O(Y[i])
);

4
techlibs/ice40/ice40_opt.cc
View file

@ -139,7 +139,8 @@ static void run_ice40_opts(Module *module)
log("Optimized $__ICE40_CARRY_WRAPPER cell back to logic (without SB_CARRY) %s.%s: CO=%s\n",
log_id(module), log_id(cell), log_signal(replacement_output));
cell->type = "$lut";
cell->setPort("\\A", { cell->getPort("\\I0"), inbit[0], inbit[1], cell->getPort("\\I3") });
auto I3 = cell->getPort(cell->getParam(ID(I3_IS_CI)).as_bool() ? ID(CI) : ID(I3));
cell->setPort("\\A", { cell->getPort("\\I0"), inbit[0], inbit[1], I3 });
cell->setPort("\\Y", cell->getPort("\\O"));
cell->unsetPort("\\B");
cell->unsetPort("\\CI");
@ -148,6 +149,7 @@ static void run_ice40_opts(Module *module)
cell->unsetPort("\\CO");
cell->unsetPort("\\O");
cell->setParam("\\WIDTH", 4);
cell->unsetParam("\\I3_IS_CI");
}
continue;
}

27
tests/arch/ice40/ice40_opt.ys
View file

@ -1,23 +1,3 @@
read_verilog -icells -formal <<EOT
module \$__ICE40_CARRY_WRAPPER (output CO, O, input A, B, CI, I0, I3);
parameter LUT = 0;
SB_CARRY carry (
.I0(A),
.I1(B),
.CI(CI),
.CO(CO)
);
\$lut #(
.WIDTH(4),
.LUT(LUT)
) lut (
.A({I0,A,B,I3}),
.Y(O)
);
endmodule
EOT
design -stash unmap
read_verilog -icells -formal <<EOT
module top(input CI, I0, output [1:0] CO, output O);
wire A = 1'b0, B = 1'b0;
@ -26,13 +6,14 @@ module top(input CI, I0, output [1:0] CO, output O);
// A[1]: 1100 1100 1100 1100
// A[2]: 1111 0000 1111 0000
// A[3]: 1111 1111 0000 0000
.LUT(~16'b 0110_1001_1001_0110)
.LUT(~16'b 0110_1001_1001_0110),
.I3_IS_CI(1'b1)
) u0 (
.A(A),
.B(B),
.CI(CI),
.I0(I0),
.I3(CI),
.I3(1'bx),
.CO(CO[0]),
.O(O)
);
@ -40,7 +21,7 @@ module top(input CI, I0, output [1:0] CO, output O);
endmodule
EOT
equiv_opt -assert -map %unmap -map +/ice40/cells_sim.v ice40_opt
equiv_opt -assert -map +/ice40/abc9_model.v -map +/ice40/cells_sim.v ice40_opt
design -load postopt
select -assert-count 1 t:*
select -assert-count 1 t:$lut