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Properly synthesize part selects.

This commit is contained in:
steve 2001-08-05 02:49:07 +00:00
parent fbf55b9df4
commit 8356e6a51f
1 changed files with 62 additions and 2 deletions
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64
expr_synth.cc
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@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#if !defined(WINNT) && !defined(macintosh)
#ident "$Id: expr_synth.cc,v 1.24 2001/07/25 03:10:49 steve Exp $"
#ident "$Id: expr_synth.cc,v 1.25 2001/08/05 02:49:07 steve Exp $"
#endif
# include "config.h"
@ -87,6 +87,17 @@ NetNet* NetEBBits::synthesize(Design*des)
assert(scope);
string path = des->local_symbol(scope->name());
if (lsig->pin_count() != rsig->pin_count()) {
cerr << get_line() << ": internal error: bitwise (" << op_
<< ") widths do not match: " << lsig->pin_count()
<< " != " << rsig->pin_count() << endl;
cerr << get_line() << ": : width="
<< lsig->pin_count() << ": " << *left_ << endl;
cerr << get_line() << ": : width="
<< rsig->pin_count() << ": " << *right_ << endl;
return 0;
}
assert(lsig->pin_count() == rsig->pin_count());
NetNet*osig = new NetNet(scope, path, NetNet::IMPLICIT,
lsig->pin_count());
@ -445,13 +456,62 @@ NetNet* NetETernary::synthesize(Design *des)
return osig;
}
/*
* When synthesizing a signal expressoin, it is usually fine to simply
* return the NetNet that it refers to. If this is a part select,
* though, a bit more work needs to be done. Return a temporary that
* represents the connections to the selected bits.
*
* For example, if there is a reg foo, like so:
* reg [5:0] foo;
* and this expression node represents a part select foo[3:2], then
* create a temporary like so:
*
* foo
* +---+
* | 5 |
* +---+
* tmp | 4 |
* +---+ +---+
* | 1 | <---> | 3 |
* +---+ +---+
* | 0 | <---> | 2 |
* +---+ +---+
* | 1 |
* +---+
* | 0 |
* +---+
* The temporary is marked as a temporary and returned to the
* caller. This causes the caller to get only the selected part of the
* signal, and when it hooks up to tmp, it hooks up to the right parts
* of foo.
*/
NetNet* NetESignal::synthesize(Design*des)
{
return net_;
if ((lsi_ == 0) && (msi_ == (net_->pin_count() - 1)))
return net_;
assert(msi_ >= lsi_);
unsigned wid = msi_ - lsi_ + 1;
NetScope*scope = net_->scope();
assert(scope);
string name = scope->name() + "." + scope->local_symbol();
NetNet*tmp = new NetNet(scope, name, NetNet::NetNet::WIRE, wid);
tmp->local_flag(true);
for (unsigned idx = 0 ; idx < wid ; idx += 1)
connect(tmp->pin(idx), net_->pin(idx+lsi_));
return tmp;
}
/*
* $Log: expr_synth.cc,v $
* Revision 1.25 2001/08/05 02:49:07 steve
* Properly synthesize part selects.
*
* Revision 1.24 2001/07/25 03:10:49 steve
* Create a config.h.in file to hold all the config
* junk, and support gcc 3.0. (Stephan Boettcher)