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Generate code for identity compare. Use gates.

This commit is contained in:
steve 2000-04-20 02:34:47 +00:00
parent 2094a2f466
commit 88d3ad51b0
1 changed files with 121 additions and 1 deletions
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122
t-xnf.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: t-xnf.cc,v 1.23 2000/02/23 02:56:55 steve Exp $"
#ident "$Id: t-xnf.cc,v 1.24 2000/04/20 02:34:47 steve Exp $"
#endif
/* XNF BACKEND
@ -81,6 +81,10 @@ class target_xnf : public target_t {
void signal(ostream&os, const NetNet*);
void lpm_add_sub(ostream&os, const NetAddSub*);
void lpm_compare(ostream&os, const NetCompare*);
void lpm_compare_eq_(ostream&os, const NetCompare*);
void lpm_compare_ge_(ostream&os, const NetCompare*);
void lpm_compare_le_(ostream&os, const NetCompare*);
void lpm_ff(ostream&os, const NetFF*);
void lpm_mux(ostream&os, const NetMux*);
void lpm_ram_dq(ostream&os, const NetRamDq*);
@ -132,6 +136,7 @@ string target_xnf::mangle(const string&name)
*/
string target_xnf::choose_sig_name(const NetObj::Link*lnk)
{
assert(lnk->is_linked());
const NetNet*sig = dynamic_cast<const NetNet*>(lnk->get_obj());
unsigned pin = lnk->get_pin();
@ -515,6 +520,118 @@ void target_xnf::lpm_add_sub(ostream&os, const NetAddSub*gate)
}
/*
* In XNF, comparators are done differently depending on the type of
* comparator being implemented. So, here we dispatch to the correct
* code generator.
*/
void target_xnf::lpm_compare(ostream&os, const NetCompare*dev)
{
if (dev->pin_AEB().is_linked()) {
lpm_compare_eq_(os, dev);
return;
}
if (dev->pin_AGEB().is_linked()) {
lpm_compare_ge_(os, dev);
return;
}
if (dev->pin_ALEB().is_linked()) {
lpm_compare_le_(os, dev);
return;
}
assert(0);
}
/*
* To compare that vectors are equal (identity comparator) generate
* XNOR gates to compare each pair of bits, then generate an AND gate
* to combine the bitwise results. This is pretty much the best way to
* do an identity compare in Xilinx CLBs.
*/
void target_xnf::lpm_compare_eq_(ostream&os, const NetCompare*dev)
{
string mname = mangle(dev->name());
/* Draw XNOR gates for each bit pair. These gates to the
bitwise comparison. */
for (unsigned idx = 0 ; idx < dev->width() ; idx += 1) {
os << "SYM, " << mname << "/cmp<" << idx << ">, "
<< "XNOR, LIBVER=2.0.0" << endl;
os << " PIN, O, O, " << mname << "/bit<" << idx << ">"
<< endl;
draw_pin(os, "I0", dev->pin_DataA(idx));
draw_pin(os, "I1", dev->pin_DataB(idx));
os << "END" << endl;
}
/* Now draw an AND gate to combine all the bitwise
comparisons. If there are more the 5 bits of data, then we
are going to have generate a nested AND to combine the
results. */
if (dev->width() > 5) {
for (unsigned idx = 0 ; idx < dev->width() ; idx += 5) {
if ((idx+1) >= dev->width()) break;
os << "SYM, " << mname << "/nest<" << idx
<< ">, AND, LIBVER=2.0.0" << endl;
os << " PIN, O, O, " << mname << "/nbit<" << idx
<< ">" << endl;
os << " PIN, I0, I, " << mname << "/bit<" << idx+0
<< ">" << endl;
os << " PIN, I1, I, " << mname << "/bit<" << idx+1
<< ">" << endl;
if ((idx+2) >= dev->width()) goto gate_out;
os << " PIN, I2, I, " << mname << "/bit<" << idx+2
<< ">" << endl;
if ((idx+3) >= dev->width()) goto gate_out;
os << " PIN, I3, I, " << mname << "/bit<" << idx+3
<< ">" << endl;
if ((idx+4) >= dev->width()) goto gate_out;
os << " PIN, I4, I, " << mname << "/bit<" << idx+4
<< ">" << endl;
gate_out:
os << "END" << endl;
}
os << "SYM, " << mname << ", AND, LIBVER=2.0.0" << endl;
draw_pin(os, "O", dev->pin_AEB());
for (unsigned idx = 0 ; idx < dev->width() ; idx += 5) {
if ((idx+1) == dev->width())
os << " PIN, I" << idx/5 << ", I " << mname
<< "/bit<" << idx << ">" << endl;
else
os << " PIN, I" << idx/5 << ", I " << mname
<< "/nbit<" << idx << ">" << endl;
}
os << "END" << endl;
} else {
os << "SYM, " << mname << ", AND, LIBVER=2.0.0" << endl;
draw_pin(os, "O", dev->pin_AEB());
for (unsigned idx = 0 ; idx < dev->width() ; idx += 1) {
os << " PIN, I" << idx << ", I, " << mname << "/bit<"
<< idx << ">" << endl;
}
os << "END" << endl;
}
}
void target_xnf::lpm_compare_ge_(ostream&os, const NetCompare*dev)
{
cerr << "XXXX GE not supported yet" << endl;
}
void target_xnf::lpm_compare_le_(ostream&os, const NetCompare*dev)
{
cerr << "XXXX LE not supported yet" << endl;
}
void target_xnf::lpm_ff(ostream&os, const NetFF*net)
{
string type = net->attribute("LPM_FFType");
@ -711,6 +828,9 @@ extern const struct target tgt_xnf = { "xnf", &target_xnf_obj };
/*
* $Log: t-xnf.cc,v $
* Revision 1.24 2000/04/20 02:34:47 steve
* Generate code for identity compare. Use gates.
*
* Revision 1.23 2000/02/23 02:56:55 steve
* Macintosh compilers do not support ident.
*