Add CONST_FLAG_UNSIZED

In order to support unsized constants being used as parameters, the `const` struct needs to know if it is unsized (so that the parameter can be used to set the size).
Add unsized flag to param value serialization and rtlil back-/front-end.
Add cell params to `tests/rtlil/everything.v`.
This commit is contained in:
Krystine Sherwin 2025-11-07 17:45:07 +13:00
parent e4c5900acd
commit 7302bf9a66
No known key found for this signature in database
5 changed files with 39 additions and 8 deletions

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@ -61,7 +61,9 @@ void RTLIL_BACKEND::dump_const(std::ostream &f, const RTLIL::Const &data, int wi
return;
}
}
f << stringf("%d'", width);
if ((data.flags & RTLIL::CONST_FLAG_UNSIZED) == 0) {
f << stringf("%d'", width);
}
if (data.flags & RTLIL::CONST_FLAG_SIGNED) {
f << stringf("s");
}
@ -172,9 +174,10 @@ void RTLIL_BACKEND::dump_cell(std::ostream &f, std::string indent, const RTLIL::
dump_attributes(f, indent, cell);
f << stringf("%s" "cell %s %s\n", indent, cell->type, cell->name);
for (const auto& [name, param] : reversed(cell->parameters)) {
f << stringf("%s parameter%s%s %s ", indent,
f << stringf("%s parameter%s%s%s %s ", indent,
(param.flags & RTLIL::CONST_FLAG_SIGNED) != 0 ? " signed" : "",
(param.flags & RTLIL::CONST_FLAG_REAL) != 0 ? " real" : "",
(param.flags & RTLIL::CONST_FLAG_UNSIZED) != 0 ? " unsized" : "",
name);
dump_const(f, param);
f << stringf("\n");

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@ -993,6 +993,8 @@ RTLIL::Const AstNode::asParaConst() const
RTLIL::Const val = asAttrConst();
if (is_signed)
val.flags |= RTLIL::CONST_FLAG_SIGNED;
if (is_unsized)
val.flags |= RTLIL::CONST_FLAG_UNSIZED;
return val;
}
@ -1766,7 +1768,10 @@ static std::string serialize_param_value(const RTLIL::Const &val) {
res.push_back('s');
if (val.flags & RTLIL::ConstFlags::CONST_FLAG_REAL)
res.push_back('r');
res += stringf("%d", GetSize(val));
if (val.flags & RTLIL::ConstFlags::CONST_FLAG_UNSIZED)
res.push_back('u');
else
res += stringf("%d", GetSize(val));
res.push_back('\'');
res.append(val.as_string("?"));
return res;
@ -1860,7 +1865,7 @@ std::string AstModule::derive_common(RTLIL::Design *design, const dict<RTLIL::Id
} else if ((it->second.flags & RTLIL::CONST_FLAG_STRING) != 0)
child->children[0] = AstNode::mkconst_str(loc, it->second.decode_string());
else
child->children[0] = AstNode::mkconst_bits(loc, it->second.to_bits(), (it->second.flags & RTLIL::CONST_FLAG_SIGNED) != 0);
child->children[0] = AstNode::mkconst_bits(loc, it->second.to_bits(), (it->second.flags & RTLIL::CONST_FLAG_SIGNED) != 0, (it->second.flags & RTLIL::CONST_FLAG_UNSIZED) != 0);
rewritten.insert(it->first);
}

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@ -567,10 +567,13 @@ struct RTLILFrontendWorker {
if (try_parse_keyword("parameter")) {
bool is_signed = false;
bool is_real = false;
bool is_unsized = false;
if (try_parse_keyword("signed")) {
is_signed = true;
} else if (try_parse_keyword("real")) {
is_real = true;
} else if (try_parse_keyword("unsized")) {
is_unsized = true;
}
RTLIL::IdString param_name = parse_id();
RTLIL::Const val = parse_const();
@ -578,6 +581,8 @@ struct RTLILFrontendWorker {
val.flags |= RTLIL::CONST_FLAG_SIGNED;
if (is_real)
val.flags |= RTLIL::CONST_FLAG_REAL;
if (is_unsized)
val.flags |= RTLIL::CONST_FLAG_UNSIZED;
cell->parameters.insert({std::move(param_name), std::move(val)});
expect_eol();
} else if (try_parse_keyword("connect")) {

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@ -53,10 +53,11 @@ namespace RTLIL
// Semantic metadata - how can this constant be interpreted?
// Values may be generally non-exclusive
enum ConstFlags : unsigned char {
CONST_FLAG_NONE = 0,
CONST_FLAG_STRING = 1,
CONST_FLAG_SIGNED = 2, // only used for parameters
CONST_FLAG_REAL = 4 // only used for parameters
CONST_FLAG_NONE = 0,
CONST_FLAG_STRING = 1,
CONST_FLAG_SIGNED = 2, // only used for parameters
CONST_FLAG_REAL = 4, // only used for parameters
CONST_FLAG_UNSIZED = 8, // only used for parameters
};
enum SelectPartials : unsigned char {

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@ -38,3 +38,20 @@ module foo(
assign b = bb;
assign y = a + bb;
endmodule
module set_param #(
parameter [3:0] VALUE = 1'bx
) (
output logic [3:0] out
);
assign out = VALUE;
endmodule
module use_param (
output logic [3:0] a, b, c, d
);
set_param #($signed(1)) spa (a);
set_param #('1) spb (b);
set_param #(1.1) spc (c);
set_param #(1'b1) spd (d);
endmodule