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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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38
techlibs/nexus/synth_nexus.cc
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@ -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");