virtual void visit(AstPin* nodep, AstNUser*) {
// PIN(p,expr) -> ASSIGNW(VARXREF(p),expr) (if sub's input)
// or ASSIGNW(expr,VARXREF(p)) (if sub's output)
UINFO(4," PIN "<<nodep<<endl);
if (debug()>=9) nodep->dumpTree(cout," Pin_oldb: ");
if (nodep->modVarp()->isOutOnly() && nodep->exprp()->castConst())
nodep->v3error("Output port is connected to a constant pin, electrical short");
// Use user1p on the PIN to indicate we created an assign for this pin
if (!nodep->user1Inc()) {
// Simplify it
V3Inst::pinReconnectSimple(nodep, m_cellp, m_modp);
// Make a ASSIGNW (expr, pin)
AstNode* exprp = nodep->exprp()->cloneTree(false);
if (nodep->width() != nodep->modVarp()->width())
nodep->v3fatalSrc("Width mismatch, should have been handled in pinReconnectSimple\n");
if (nodep->modVarp()->isInout()) {
nodep->v3fatalSrc("Unsupported: Verilator is a 2-state simulator");
} else if (nodep->modVarp()->isOutput()) {
AstNode* rhsp = new AstVarXRef (exprp->fileline(), nodep->modVarp(), m_cellp->name(), false);
rhsp->widthSignedFrom(nodep);
AstAssignW* assp = new AstAssignW (exprp->fileline(), exprp, rhsp);
m_modp->addStmtp(assp);
} else if (nodep->modVarp()->isInput()) {
// Don't bother moving constants now,
// we'll be pushing the const down to the cell soon enough.
AstNode* assp = new AstAssignW
(exprp->fileline(),
new AstVarXRef(exprp->fileline(), nodep->modVarp(), m_cellp->name(), true),
exprp);
m_modp->addStmtp(assp);
if (debug()>=9) assp->dumpTree(cout," _new: ");
} else {
nodep->v3error("Assigned pin is neither input nor output");
}
}
// We're done with the pin
nodep->unlinkFrBack()->deleteTree(); nodep=NULL;
}
void V3Inst::pinReconnectSimple(AstPin* pinp, AstCell* cellp, AstNodeModule* modp) {
// If a pin connection is "simple" leave it as-is
// Else create a intermediate wire to perform the interconnect
// Note this module calles cloneTree() via new AstVar
AstVar* pinVarp = pinp->modVarp();
AstVarRef* connectRefp = pinp->exprp()->castVarRef();
AstBasicDType* pinBasicp = pinVarp->dtypep()->basicp(); // Maybe NULL
AstBasicDType* connBasicp = NULL;
if (connectRefp) connBasicp = connectRefp->varp()->dtypep()->basicp();
//
if (connectRefp
&& connectRefp->varp()->dtypep()->sameTree(pinVarp->dtypep())
&& !connectRefp->varp()->isSc()) { // Need the signal as a 'shell' to convert types
// Done. Same data type
} else if (connBasicp
&& pinBasicp
&& connBasicp->width() == pinBasicp->width()
&& connBasicp->lsb() == pinBasicp->lsb()
&& !connectRefp->varp()->isSc() // Need the signal as a 'shell' to convert types
&& pinp->width() == pinVarp->width()
&& 1) {
// Done. One to one interconnect won't need a temporary variable.
} else if (pinp->exprp()->castConst()) {
// Done. Constant.
} else {
// Make a new temp wire
//if (1||debug()>=9) { pinp->dumpTree(cout,"in_pin:"); }
AstAssignW* assignp = NULL;
AstNode* pinexprp = pinp->exprp()->unlinkFrBack();
string newvarname = "__Vcellinp__"+cellp->name()+"__"+pinp->name();
AstVar* newvarp = new AstVar (pinVarp->fileline(), AstVarType::MODULETEMP, newvarname, pinVarp);
modp->addStmtp(newvarp);
if (pinVarp->isInout()) {
pinVarp->v3fatalSrc("Unsupported: Inout connections to pins must be direct one-to-one connection (without any expression)");
} else if (pinVarp->isOutput()) {
// See also V3Inst
AstNode* rhsp = new AstVarRef(pinp->fileline(), newvarp, false);
if (pinp->width() > rhsp->width()) {
if (rhsp->isSigned()) {
rhsp = new AstExtendS(pinp->fileline(), rhsp);
} else {
rhsp = new AstExtend (pinp->fileline(), rhsp);
}
} else if (pinp->width() < rhsp->width()) {
rhsp = new AstSel (pinp->fileline(), rhsp, 0, pinp->width());
}
rhsp->widthSignedFrom(pinp);
assignp = new AstAssignW (pinp->fileline(), pinexprp, rhsp);
pinp->exprp(new AstVarRef (pinexprp->fileline(), newvarp, true));
} else {
// V3 width should have range/extended to make the widths correct
if (pinexprp->width() != pinVarp->width()) pinp->v3fatalSrc("Input pin width mismatch");
assignp = new AstAssignW (pinp->fileline(),
new AstVarRef(pinp->fileline(), newvarp, true),
pinexprp);
pinp->exprp(new AstVarRef (pinexprp->fileline(), newvarp, false));
}
pinp->widthSignedFrom(pinp->exprp());
if (assignp) modp->addStmtp(assignp);
//if (1||debug()) { pinp->dumpTree(cout," out:"); }
//if (1||debug()) { assignp->dumpTree(cout," aout:"); }
}
}
