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Elaborate net of real-value constant 

Handle the special case of a unary minus net with the operand
that is a real-valued constant.
This commit is contained in:
Stephen Williams 2008-01-06 19:59:31 -08:00
parent bafd705478
commit 9d55597b26
2 changed files with 101 additions and 36 deletions
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18
PExpr.h
View File

@ -486,6 +486,24 @@ class PEUnary : public PExpr {
virtual bool is_constant(Module*) const;
private:
NetNet* elab_net_uminus_const_logic_(Design*des, NetScope*scope,
NetEConst*expr,
unsigned width,
const NetExpr* rise,
const NetExpr* fall,
const NetExpr* decay,
Link::strength_t drive0,
Link::strength_t drive1) const;
NetNet* elab_net_uminus_const_real_(Design*des, NetScope*scope,
NetECReal*expr,
unsigned width,
const NetExpr* rise,
const NetExpr* fall,
const NetExpr* decay,
Link::strength_t drive0,
Link::strength_t drive1) const;
private:
char op_;
PExpr*expr_;

119
elab_net.cc
View File

@ -2930,6 +2930,7 @@ NetNet* PEUnary::elaborate_net(Design*des, NetScope*scope,
Link::strength_t drive0,
Link::strength_t drive1) const
{
NetExpr*expr = elab_and_eval(des, scope, expr_, width);
// Some unary operands allow the operand to be
// self-determined, and some do not.
@ -2948,45 +2949,21 @@ NetNet* PEUnary::elaborate_net(Design*des, NetScope*scope,
// Handle the special case of a 2's complement of a constant
// value. This can be reduced to a no-op on a precalculated
// result.
if (op_ == '-') do {
// TODO: Should replace this with a call to
// elab_and_eval. Possibly blend this with the rest of
// the elaboration as well.
verinum*val = expr_->eval_const(des, scope);
if (val == 0)
break;
if (width == 0)
width = val->len();
assert(width > 0);
sig = new NetNet(scope, scope->local_symbol(),
NetNet::WIRE, width);
sig->data_type(IVL_VT_LOGIC);
sig->local_flag(true);
/* Take the 2s complement by taking the 1s complement
and adding 1. */
verinum tmp (v_not(*val), width);
verinum one (1UL, width);
tmp = verinum(tmp + one, width);
tmp.has_sign(val->has_sign());
NetConst*con = new NetConst(scope, scope->local_symbol(), tmp);
connect(sig->pin(0), con->pin(0));
if (debug_elaborate) {
cerr << get_fileline() << ": debug: Replace expression "
<< *this << " with constant " << tmp << "."<<endl;
if (op_ == '-') {
if (NetEConst*tmp = dynamic_cast<NetEConst*>(expr)) {
return elab_net_uminus_const_logic_(des, scope, tmp,
width, rise, fall, decay,
drive0, drive1);
}
delete val;
des->add_node(con);
return sig;
if (NetECReal*tmp = dynamic_cast<NetECReal*>(expr)) {
return elab_net_uminus_const_real_(des, scope, tmp,
width, rise, fall, decay,
drive0, drive1);
}
}
} while (0);
NetNet* sub_sig = expr_->elaborate_net(des, scope, owidth, 0, 0, 0);
NetNet* sub_sig = expr->synthesize(des);
if (sub_sig == 0) {
des->errors += 1;
return 0;
@ -3115,3 +3092,73 @@ NetNet* PEUnary::elaborate_net(Design*des, NetScope*scope,
return sig;
}
NetNet* PEUnary::elab_net_uminus_const_logic_(Design*des, NetScope*scope,
NetEConst*expr,
unsigned width,
const NetExpr* rise,
const NetExpr* fall,
const NetExpr* decay,
Link::strength_t drive0,
Link::strength_t drive1) const
{
verinum val = expr->value();
if (width == 0)
width = val.len();
assert(width > 0);
NetNet*sig = new NetNet(scope, scope->local_symbol(),
NetNet::WIRE, width);
sig->data_type(IVL_VT_LOGIC);
sig->local_flag(true);
/* Take the 2s complement by taking the 1s complement
and adding 1. */
verinum tmp (v_not(val), width);
verinum one (1UL, width);
tmp = verinum(tmp + one, width);
tmp.has_sign(val.has_sign());
NetConst*con = new NetConst(scope, scope->local_symbol(), tmp);
connect(sig->pin(0), con->pin(0));
if (debug_elaborate) {
cerr << get_fileline() << ": debug: Replace expression "
<< *this << " with constant " << tmp << "."<<endl;
}
delete expr;
des->add_node(con);
return sig;
}
NetNet* PEUnary::elab_net_uminus_const_real_(Design*des, NetScope*scope,
NetECReal*expr,
unsigned width,
const NetExpr* rise,
const NetExpr* fall,
const NetExpr* decay,
Link::strength_t drive0,
Link::strength_t drive1) const
{
verireal val = expr->value();
NetNet*sig = new NetNet(scope, scope->local_symbol(),
NetNet::WIRE, width);
sig->data_type(IVL_VT_REAL);
sig->local_flag(true);
NetLiteral*con = new NetLiteral(scope, scope->local_symbol(), -val);
connect(con->pin(0), sig->pin(0));
des->add_node(con);
if (debug_elaborate) {
cerr << get_fileline() << ": debug: Replace expression "
<< *this << " with constant " << con->value_real() << "."<<endl;
}
delete expr;
return sig;
}