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nexus: DSP inference support

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Signed-off-by: David Shah <dave@ds0.me>
This commit is contained in:
David Shah 2020-11-20 08:26:58 +00:00
parent 5b35d953f7
commit 9f241c9a42
4 changed files with 151 additions and 13 deletions
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1
techlibs/nexus/Makefile.inc
View file

@ -11,4 +11,5 @@ $(eval $(call add_share_file,share/nexus,techlibs/nexus/brams_map.v))
$(eval $(call add_share_file,share/nexus,techlibs/nexus/brams.txt))
$(eval $(call add_share_file,share/nexus,techlibs/nexus/arith_map.v))
$(eval $(call add_share_file,share/nexus,techlibs/nexus/latches_map.v))
$(eval $(call add_share_file,share/nexus,techlibs/nexus/dsp_map.v))

79
techlibs/nexus/dsp_map.v Normal file
View file

@ -0,0 +1,79 @@
module \$__NX_MUL36X36 (input [35:0] A, input [35:0] B, output [71:0] Y);
parameter A_WIDTH = 36;
parameter B_WIDTH = 36;
parameter Y_WIDTH = 72;
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
MULT36X36 #(
.REGINPUTA("BYPASS"),
.REGINPUTB("BYPASS"),
.REGOUTPUT("BYPASS")
) _TECHMAP_REPLACE_ (
.A(A), .B(B),
.SIGNEDA(A_SIGNED ? 1'b1 : 1'b0),
.SIGNEDB(B_SIGNED ? 1'b1 : 1'b0),
.Z(Y)
);
endmodule
module \$__NX_MUL36X18 (input [35:0] A, input [17:0] B, output [53:0] Y);
parameter A_WIDTH = 36;
parameter B_WIDTH = 18;
parameter Y_WIDTH = 54;
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
MULT18X36 #(
.REGINPUTA("BYPASS"),
.REGINPUTB("BYPASS"),
.REGOUTPUT("BYPASS")
) _TECHMAP_REPLACE_ (
.A(B), .B(A),
.SIGNEDA(B_SIGNED ? 1'b1 : 1'b0),
.SIGNEDB(A_SIGNED ? 1'b1 : 1'b0),
.Z(Y)
);
endmodule
module \$__NX_MUL18X18 (input [17:0] A, input [17:0] B, output [35:0] Y);
parameter A_WIDTH = 18;
parameter B_WIDTH = 18;
parameter Y_WIDTH = 36;
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
MULT18X18 #(
.REGINPUTA("BYPASS"),
.REGINPUTB("BYPASS"),
.REGOUTPUT("BYPASS")
) _TECHMAP_REPLACE_ (
.A(A), .B(B),
.SIGNEDA(A_SIGNED ? 1'b1 : 1'b0),
.SIGNEDB(B_SIGNED ? 1'b1 : 1'b0),
.Z(Y)
);
endmodule
module \$__NX_MUL9X9 (input [8:0] A, input [8:0] B, output [17:0] Y);
parameter A_WIDTH = 9;
parameter B_WIDTH = 9;
parameter Y_WIDTH = 18;
parameter A_SIGNED = 0;
parameter B_SIGNED = 0;
MULT9X9 #(
.REGINPUTA("BYPASS"),
.REGINPUTB("BYPASS"),
.REGOUTPUT("BYPASS")
) _TECHMAP_REPLACE_ (
.A(A), .B(B),
.SIGNEDA(A_SIGNED ? 1'b1 : 1'b0),
.SIGNEDB(B_SIGNED ? 1'b1 : 1'b0),
.Z(Y)
);
endmodule

38
techlibs/nexus/synth_nexus.cc
View file

@ -89,6 +89,9 @@ struct SynthNexusPass : public ScriptPass
log(" -noiopad\n");
log(" do not insert IO buffers\n");
log("\n");
log(" -nodsp\n");
log(" do not infer DSP multipliers\n");
log("\n");
log(" -abc9\n");
log(" use new ABC9 flow (EXPERIMENTAL)\n");
log("\n");
@ -98,7 +101,7 @@ struct SynthNexusPass : public ScriptPass
}
string top_opt, json_file, vm_file, family;
bool noccu2, nodffe, nobram, nolutram, nowidelut, noiopad, flatten, dff, retime, abc9;
bool noccu2, nodffe, nobram, nolutram, nowidelut, noiopad, nodsp, flatten, dff, retime, abc9;
void clear_flags() override
{
@ -112,6 +115,7 @@ struct SynthNexusPass : public ScriptPass
nolutram = false;
nowidelut = false;
noiopad = false;
nodsp = false;
flatten = true;
dff = false;
retime = false;
@ -161,6 +165,10 @@ struct SynthNexusPass : public ScriptPass
dff = true;
continue;
}
if (args[argidx] == "-nodsp") {
nodsp = true;
continue;
}
if (args[argidx] == "-retime") {
retime = true;
continue;
@ -211,6 +219,22 @@ struct SynthNexusPass : public ScriptPass
log_pop();
}
struct DSPRule {
int a_maxwidth;
int b_maxwidth;
int a_minwidth;
int b_minwidth;
std::string prim;
};
const std::vector<DSPRule> dsp_rules = {
{36, 36, 22, 22, "$__NX_MUL36X36"},
{36, 18, 22, 10, "$__NX_MUL36X18"},
{18, 18, 10, 4, "$__NX_MUL18X18"},
{18, 18, 4, 10, "$__NX_MUL18X18"},
{ 9, 9, 4, 4, "$__NX_MUL9X9"},
};
void script() override
{
@ -244,6 +268,18 @@ struct SynthNexusPass : public ScriptPass
run("opt_expr");
run("opt_clean");
if (help_mode) {
run("techmap -map +/mul2dsp.v [...]", "(unless -nodsp)");
run("techmap -map +/nexus/dsp_map.v", "(unless -nodsp)");
} else if (!nodsp) {
for (const auto &rule : dsp_rules) {
run(stringf("techmap -map +/mul2dsp.v -D DSP_A_MAXWIDTH=%d -D DSP_B_MAXWIDTH=%d -D DSP_A_MINWIDTH=%d -D DSP_B_MINWIDTH=%d -D DSP_NAME=%s",
rule.a_maxwidth, rule.b_maxwidth, rule.a_minwidth, rule.b_minwidth, rule.prim.c_str()));
run("chtype -set $mul t:$__soft_mul");
}
run("techmap -map +/nexus/dsp_map.v");
}
run("alumacc");
run("opt");
run("memory -nomap");