Elaborate net widths of constants to as small
as is possible, obeying context constraints. Comparison operators can handle operands with different widths.
This commit is contained in:
steve
parent
f37f69f160
commit
3d1ffced57
191
elab_net.cc
191
elab_net.cc
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@ -17,7 +17,7 @@
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#if !defined(WINNT)
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#ident "$Id: elab_net.cc,v 1.17 2000/01/02 22:07:09 steve Exp $"
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#ident "$Id: elab_net.cc,v 1.18 2000/01/11 04:20:57 steve Exp $"
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#endif
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# include "PExpr.h"
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@ -246,7 +246,10 @@ NetNet* PEBinary::elaborate_net_add_(Design*des, const string&path,
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}
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/*
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* Elaborate the various binary comparison operators.
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* Elaborate the various binary comparison operators. The comparison
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* operators return a single bit result, no matter what, so the left
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* and right values can have their own size. The only restriction is
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* that they have the same size.
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*/
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NetNet* PEBinary::elaborate_net_cmp_(Design*des, const string&path,
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unsigned lwidth,
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@ -269,6 +272,7 @@ NetNet* PEBinary::elaborate_net_cmp_(Design*des, const string&path,
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return 0;
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}
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#if 0
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if (lsig->pin_count() != rsig->pin_count()) {
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cerr << get_line() << ": internal error: Cannot match "
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"structural net widths " << lsig->pin_count() <<
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@ -278,24 +282,42 @@ NetNet* PEBinary::elaborate_net_cmp_(Design*des, const string&path,
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des->errors += 1;
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return 0;
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}
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#endif
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unsigned dwidth = lsig->pin_count();
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if (rsig->pin_count() > dwidth) dwidth = rsig->pin_count();
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NetNet*zero = 0;
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if (lsig->pin_count() != rsig->pin_count()) {
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NetConst*tmp = new NetConst(des->local_symbol(path), verinum::V0);
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des->add_node(tmp);
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zero = new NetNet(0, des->local_symbol(path), NetNet::WIRE);
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des->add_signal(zero);
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connect(tmp->pin(0), zero->pin(0));
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}
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NetNet*osig = new NetNet(0, des->local_symbol(path), NetNet::WIRE);
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osig->local_flag(true);
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NetNode*gate;
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NetNode*gate_t;
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//NetNode*gate_t;
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switch (op_) {
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case '<':
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case '>':
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case 'L':
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case 'G': {
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NetCompare*cmp = new NetCompare(des->local_symbol(path),
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lsig->pin_count());
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for (unsigned idx = 0 ; idx < lsig->pin_count() ; idx += 1) {
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NetCompare*cmp = new
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NetCompare(des->local_symbol(path), dwidth);
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for (unsigned idx = 0 ; idx < lsig->pin_count() ; idx += 1)
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connect(cmp->pin_DataA(idx), lsig->pin(idx));
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for (unsigned idx = lsig->pin_count(); idx < dwidth ; idx += 1)
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connect(cmp->pin_DataA(idx), zero->pin(0));
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for (unsigned idx = 0 ; idx < rsig->pin_count() ; idx += 1)
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connect(cmp->pin_DataB(idx), rsig->pin(idx));
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}
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for (unsigned idx = rsig->pin_count(); idx < dwidth ; idx += 1)
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connect(cmp->pin_DataB(idx), zero->pin(0));
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switch (op_) {
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case '<':
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connect(cmp->pin_ALB(), osig->pin(0));
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@ -321,18 +343,27 @@ NetNet* PEBinary::elaborate_net_cmp_(Design*des, const string&path,
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1+lsig->pin_count(),
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NetLogic::AND);
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connect(gate->pin(0), osig->pin(0));
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for (unsigned idx = 0 ; idx < lsig->pin_count() ; idx += 1) {
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gate_t = new NetCaseCmp(des->local_symbol(path));
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connect(gate_t->pin(1), lsig->pin(idx));
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connect(gate_t->pin(2), rsig->pin(idx));
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connect(gate_t->pin(0), gate->pin(idx+1));
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des->add_node(gate_t);
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for (unsigned idx = 0 ; idx < dwidth ; idx += 1) {
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NetCaseCmp*cmp = new NetCaseCmp(des->local_symbol(path));
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if (idx < lsig->pin_count())
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connect(cmp->pin(1), lsig->pin(idx));
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else
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connect(cmp->pin(1), zero->pin(0));
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if (idx < rsig->pin_count())
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connect(cmp->pin(2), rsig->pin(idx));
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else
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connect(cmp->pin(2), zero->pin(0));
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connect(cmp->pin(0), gate->pin(idx+1));
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des->add_node(cmp);
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// Attach a label to this intermediate wire
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NetNet*tmp = new NetNet(0, des->local_symbol(path),
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NetNet::WIRE);
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tmp->local_flag(true);
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connect(gate_t->pin(0), tmp->pin(0));
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connect(cmp->pin(0), tmp->pin(0));
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des->add_signal(tmp);
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}
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break;
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@ -340,31 +371,57 @@ NetNet* PEBinary::elaborate_net_cmp_(Design*des, const string&path,
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case 'e': // ==
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gate = new NetLogic(des->local_symbol(path),
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1+lsig->pin_count(),
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NetLogic::AND);
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1+dwidth,NetLogic::AND);
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connect(gate->pin(0), osig->pin(0));
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for (unsigned idx = 0 ; idx < lsig->pin_count() ; idx += 1) {
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gate_t = new NetLogic(des->local_symbol(path), 3,
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NetLogic::XNOR);
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connect(gate_t->pin(1), lsig->pin(idx));
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connect(gate_t->pin(2), rsig->pin(idx));
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connect(gate_t->pin(0), gate->pin(idx+1));
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des->add_node(gate_t);
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for (unsigned idx = 0 ; idx < dwidth ; idx += 1) {
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NetLogic*cmp = new NetLogic(des->local_symbol(path),
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3, NetLogic::XNOR);
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if (idx < lsig->pin_count())
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connect(cmp->pin(1), lsig->pin(idx));
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else
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connect(cmp->pin(1), zero->pin(0));
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if (idx < rsig->pin_count())
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connect(cmp->pin(2), rsig->pin(idx));
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else
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connect(cmp->pin(2), zero->pin(0));
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connect(cmp->pin(0), gate->pin(idx+1));
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des->add_node(cmp);
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NetNet*tmp = new NetNet(0, des->local_symbol(path),
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NetNet::WIRE);
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tmp->local_flag(true);
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connect(cmp->pin(0), tmp->pin(0));
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des->add_signal(tmp);
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}
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break;
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case 'n': // !=
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gate = new NetLogic(des->local_symbol(path),
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1+lsig->pin_count(),
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NetLogic::OR);
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1+dwidth, NetLogic::OR);
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connect(gate->pin(0), osig->pin(0));
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for (unsigned idx = 0 ; idx < lsig->pin_count() ; idx += 1) {
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gate_t = new NetLogic(des->local_symbol(path), 3,
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NetLogic::XOR);
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connect(gate_t->pin(1), lsig->pin(idx));
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connect(gate_t->pin(2), rsig->pin(idx));
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connect(gate_t->pin(0), gate->pin(idx+1));
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des->add_node(gate_t);
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NetLogic*cmp = new NetLogic(des->local_symbol(path), 3,
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NetLogic::XOR);
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if (idx < lsig->pin_count())
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connect(cmp->pin(1), lsig->pin(idx));
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else
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connect(cmp->pin(1), zero->pin(0));
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if (idx < rsig->pin_count())
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connect(cmp->pin(2), rsig->pin(idx));
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else
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connect(cmp->pin(2), zero->pin(0));
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connect(cmp->pin(0), gate->pin(idx+1));
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des->add_node(cmp);
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NetNet*tmp = new NetNet(0, des->local_symbol(path),
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NetNet::WIRE);
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tmp->local_flag(true);
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connect(cmp->pin(0), tmp->pin(0));
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des->add_signal(tmp);
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}
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break;
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@ -899,14 +956,73 @@ NetNet* PENumber::elaborate_net(Design*des, const string&path,
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unsigned long fall,
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unsigned long decay) const
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{
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/* If we are constrained by a l-value size, then just make a
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number constant with the correct size and set as many bits
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in that constant as make sense. Pad excess with zeros. */
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if (lwidth > 0) {
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NetNet*net = new NetNet(0, des->local_symbol(path),
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NetNet::IMPLICIT, lwidth);
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net->local_flag(true);
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verinum num(verinum::V0, net->pin_count());
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unsigned idx;
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for (idx = 0 ; idx < num.len() && idx < value_->len(); idx += 1)
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num.set(idx, value_->get(idx));
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NetConst*tmp = new NetConst(des->local_symbol(path), num);
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for (idx = 0 ; idx < net->pin_count() ; idx += 1)
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connect(net->pin(idx), tmp->pin(idx));
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des->add_node(tmp);
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des->add_signal(net);
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return net;
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}
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/* If the number has a length, then use that to size the
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number. Generate a constant object of exactly the user
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specified size. */
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if (value_->has_len()) {
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NetNet*net = new NetNet(0, des->local_symbol(path),
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NetNet::IMPLICIT, value_->len());
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net->local_flag(true);
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NetConst*tmp = new NetConst(des->local_symbol(path), *value_);
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for (unsigned idx = 0 ; idx < value_->len() ; idx += 1)
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connect(net->pin(idx), tmp->pin(idx));
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des->add_node(tmp);
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des->add_signal(net);
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return net;
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}
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/* None of the above tight constraints are present, so make a
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plausible choice for the width. Try to reduce the width as
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much as possible by eliminating high zeros of unsigned
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numbers. */
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unsigned width = value_->len();
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if ((lwidth > 0) && (lwidth < width))
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width = lwidth;
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if (value_->has_sign() && (value_->get(width-1) == verinum::V0)) {
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/* If the number is signed, but known to be positive,
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then reduce it down as if it were unsigned. */
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while (width > 1) {
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if (value_->get(width-1) != verinum::V0)
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break;
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width -= 1;
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}
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} else if (value_->has_sign() == false) {
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while ( (width > 1) && (value_->get(width-1) == verinum::V0))
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width -= 1;
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}
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verinum num (verinum::V0, width);
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for (unsigned idx = 0 ; idx < width ; idx += 1)
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num.set(idx, value_->get(idx));
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NetNet*net = new NetNet(0, des->local_symbol(path),
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NetNet::IMPLICIT, width);
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net->local_flag(true);
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NetConst*tmp = new NetConst(des->local_symbol(path), *value_);
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NetConst*tmp = new NetConst(des->local_symbol(path), num);
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for (unsigned idx = 0 ; idx < width ; idx += 1)
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connect(net->pin(idx), tmp->pin(idx));
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@ -1108,6 +1224,13 @@ NetNet* PEUnary::elaborate_net(Design*des, const string&path,
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/*
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* $Log: elab_net.cc,v $
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* Revision 1.18 2000/01/11 04:20:57 steve
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* Elaborate net widths of constants to as small
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* as is possible, obeying context constraints.
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*
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* Comparison operators can handle operands with
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* different widths.
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*
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* Revision 1.17 2000/01/02 22:07:09 steve
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* Add a signal to nexus of padding constant.
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*
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