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Support randcase.

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This commit is contained in:
Wilson Snyder
2022-11-11 21:53:05 -05:00
parent 41d2ebe288
commit a427860825
11 changed files with 243 additions and 3 deletions
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src/V3Randomize.cpp
+69
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@@ -100,6 +100,7 @@ private:
markMembers(classp);
}
}
void visit(AstNode* nodep) override { iterateChildren(nodep); }
public:
@@ -124,7 +125,9 @@ private:
const VNUser2InUse m_inuser2;
// STATE
AstNodeModule* m_modp = nullptr; // Current module
size_t m_enumValueTabCount = 0; // Number of tables with enum values created
int m_randCaseNum = 0; // Randcase number within a module for var naming
// METHODS
AstVar* enumValueTabp(AstEnumDType* nodep) {
@@ -197,7 +200,16 @@ private:
}
// VISITORS
void visit(AstNodeModule* nodep) override {
VL_RESTORER(m_randCaseNum);
m_modp = nodep;
m_randCaseNum = 0;
iterateChildren(nodep);
}
void visit(AstClass* nodep) override {
VL_RESTORER(m_randCaseNum);
m_modp = nodep;
m_randCaseNum = 0;
iterateChildren(nodep);
if (!nodep->user1()) return; // Doesn't need randomize, or already processed
UINFO(9, "Define randomize() for " << nodep << endl);
@@ -239,6 +251,63 @@ private:
}
nodep->user1(false);
}
void visit(AstRandCase* nodep) override {
// RANDCASE
// CASEITEM expr1 : stmt1
// CASEITEM expr2 : stmt2
// ->
// tmp = URandomRange{0, num} + 1 // + 1 so weight 0 means never
// if (tmp < expr1) stmt1;
// else if (tmp < (expr2 + expr1)) stmt1;
// else warning
// Note this code assumes that the expressions after V3Const are fast to compute
// Optimize: we would be better with a binary search tree to reduce ifs that execute
if (debug() >= 9) nodep->dumpTree(cout, "-rcin: ");
AstNodeDType* const sumDTypep = nodep->findUInt64DType();
FileLine* const fl = nodep->fileline();
const std::string name = "__Vrandcase" + cvtToStr(m_randCaseNum++);
AstVar* const randVarp = new AstVar{fl, VVarType::STMTTEMP, name, sumDTypep};
randVarp->noSubst(true);
AstNodeExpr* sump = new AstConst{fl, AstConst::WidthedValue{}, 64, 0};
AstNodeIf* firstIfsp
= new AstIf{fl, new AstConst{fl, AstConst::BitFalse{}}, nullptr, nullptr};
AstNodeIf* ifsp = firstIfsp;
for (AstCaseItem* itemp = nodep->itemsp(); itemp;
itemp = VN_AS(itemp->nextp(), CaseItem)) {
AstNode* const condp = itemp->condsp()->unlinkFrBack();
sump
= new AstAdd{condp->fileline(), sump, new AstExtend{itemp->fileline(), condp, 64}};
AstNode* const stmtsp
= itemp->stmtsp() ? itemp->stmtsp()->unlinkFrBackWithNext() : nullptr;
AstNodeIf* const newifp
= new AstIf{itemp->fileline(),
new AstLte{condp->fileline(),
new AstVarRef{condp->fileline(), randVarp, VAccess::READ},
sump->cloneTree(true)},
stmtsp, nullptr};
ifsp->addElsesp(newifp);
ifsp = newifp;
}
AstDisplay* dispp = new AstDisplay{
fl, VDisplayType::DT_ERROR, "All randcase items had 0 weights (IEEE 1800-2017 18.16)",
nullptr, nullptr};
UASSERT_OBJ(m_modp, nodep, "randcase not under module");
dispp->fmtp()->timeunit(m_modp->timeunit());
ifsp->addElsesp(dispp);
AstNode* newp = randVarp;
AstNode* randp = new AstRand{fl, nullptr, false};
randp->dtypeSetUInt64();
newp->addNext(new AstAssign{fl, new AstVarRef{fl, randVarp, VAccess::WRITE},
new AstAdd{fl, new AstConst{fl, AstConst::Unsized64{}, 1},
new AstModDiv{fl, randp, sump}}});
newp->addNext(firstIfsp);
if (debug() >= 9) newp->dumpTreeAndNext(cout, "-rcnew: ");
nodep->replaceWith(newp);
VL_DO_DANGLING(pushDeletep(nodep), nodep);
}
void visit(AstNode* nodep) override { iterateChildren(nodep); }
public: