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Handle DFF definitions spread out within a block.

This commit is contained in:
steve 2005-12-19 01:13:47 +00:00
parent 3429c24a6a
commit def3809b3f
1 changed files with 125 additions and 36 deletions
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161
synth2.cc
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@ -17,7 +17,7 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#ifdef HAVE_CVS_IDENT
#ident "$Id: synth2.cc,v 1.39.2.11 2005/12/15 02:38:51 steve Exp $"
#ident "$Id: synth2.cc,v 1.39.2.12 2005/12/19 01:13:47 steve Exp $"
#endif
# include "config.h"
@ -58,14 +58,13 @@ bool NetProc::synth_sync(Design*des, NetScope*scope, NetFF*ff,
NetNet*nex_map, NetNet*nex_out,
const svector<NetEvProbe*>&events)
{
DEBUG_SYNTH2_ENTRY("NetProc")
#if 0
if (events.count() > 0) {
cerr << get_line() << ": error: Events are unaccounted"
<< " for in process synthesis." << endl;
<< " for in process synthesis. (proc)" << endl;
des->errors += 1;
}
#endif
/* Synthesize the input to the DFF. */
return synth_async(des, scope, true, nex_map, nex_out);
}
@ -630,6 +629,50 @@ bool NetProcTop::synth_async(Design*des)
return flag;
}
static bool merge_ff_slices(NetFF*ff1, unsigned idx1,
NetFF*ff2, unsigned idx2)
{
/* If the Data inputs to both FFs are connected, then there
are multiple descriptions of the inputs to this DFF
device. That is an error. */
if (ff1->pin_Data(idx1).is_linked() && ff2->pin_Data(idx2).is_linked()) {
cerr << ff2->get_line() << ": error: "
<< "Synchronous output conflicts with "
<< ff1->get_line() << "." << endl;
return false;
}
/* If the Aset inputs are connected, and not to each other
(possible since pre-existing Asets are carried forwards)
then there is a conflict. */
if (ff1->pin_Aset().is_linked()
&& ff2->pin_Aset().is_linked()
&& ! ff1->pin_Aset().is_linked(ff2->pin_Aset())) {
cerr << ff2->get_line() << ": error: "
<< "DFF Aset conflicts with "
<< ff1->get_line() << "." << endl;
return false;
}
if (ff1->pin_Aclr().is_linked()
&& ff2->pin_Aclr().is_linked()
&& ! ff1->pin_Aclr().is_linked(ff2->pin_Aclr())) {
cerr << ff2->get_line() << ": error: "
<< "DFF Aclr conflicts with "
<< ff1->get_line() << "." << endl;
return false;
}
if (ff2->pin_Data(idx2).is_linked())
connect(ff1->pin_Data(idx1), ff2->pin_Data(idx2));
if (ff2->pin_Aset().is_linked())
connect(ff1->pin_Aset(), ff2->pin_Aset());
if (ff2->pin_Aclr().is_linked())
connect(ff1->pin_Aclr(), ff2->pin_Aclr());
return true;
}
/*
* This method is called when a block is encountered near the surface
* of a synchronous always statement. For example, this code will be
@ -648,11 +691,9 @@ bool NetBlock::synth_sync(Design*des, NetScope*scope, NetFF*ff,
NetNet*nex_map, NetNet*nex_out,
const svector<NetEvProbe*>&events_in)
{
DEBUG_SYNTH2_ENTRY("NetBlock")
if (last_ == 0) {
DEBUG_SYNTH2_EXIT("NetBlock",true)
/* Do nothing for empty blocks. */
if (last_ == 0)
return true;
}
bool flag = true;
@ -660,10 +701,19 @@ bool NetBlock::synth_sync(Design*des, NetScope*scope, NetFF*ff,
const perm_string tmp2 = perm_string::literal("tmp2");
/* Keep an accounting of which statement accounts for which
bit slice of the FF bank. This is used for error checking. */
NetProc**pin_accounting = new NetProc* [ff->pin_count()];
for (unsigned idx = 0 ; idx < ff->pin_count() ; idx += 1)
pin_accounting[idx] = 0;
bit slice of the FF bank. This is used for error
checking. */
struct accounting_struct {
NetProc*proc;
NetFF*ff;
unsigned pin;
};
struct accounting_struct*pin_accounting
= new accounting_struct [ff->pin_count()];
for (unsigned idx = 0 ; idx < ff->pin_count() ; idx += 1) {
pin_accounting[idx].proc = 0;
pin_accounting[idx].ff = 0;
}
NetProc*cur = last_;
do {
@ -698,6 +748,7 @@ bool NetBlock::synth_sync(Design*des, NetScope*scope, NetFF*ff,
copy the aset_value bits for the new ff device. */
NetFF*ff2 = new NetFF(scope, scope->local_symbol(),
tmp_out->pin_count());
ff2->set_line(*cur);
des->add_node(ff2);
verinum aset_value2 (verinum::V1, ff2->width());
@ -706,10 +757,6 @@ bool NetBlock::synth_sync(Design*des, NetScope*scope, NetFF*ff,
unsigned ptr = find_nexus_in_set(nex_map,
tmp_map->pin(idx).nexus());
/* Connect Data and Q bits to the new FF. */
connect(ff->pin_Data(ptr), ff2->pin_Data(idx));
connect(ff->pin_Q(ptr), ff2->pin_Q(idx));
/* Copy the asynch set bit to the new device. */
if (ptr < tmp_aset.len())
aset_value2.set(idx, tmp_aset[ptr]);
@ -718,18 +765,21 @@ bool NetBlock::synth_sync(Design*des, NetScope*scope, NetFF*ff,
if (ptr < tmp_sset.len())
sset_value2.set(idx, tmp_sset[ptr]);
if (pin_accounting[ptr] != 0) {
cerr << cur->get_line() << ": error: "
<< "Synchronous output conflicts with "
<< pin_accounting[ptr]->get_line()
<< "." << endl;
flag = false;
if (pin_accounting[ptr].proc != 0) {
} else {
pin_accounting[ptr] = cur;
pin_accounting[ptr].proc = cur;
pin_accounting[ptr].ff = ff2;
pin_accounting[ptr].pin = idx;
/* Connect Data and Q bits to the new FF. */
connect(ff->pin_Data(ptr), ff2->pin_Data(idx));
connect(ff->pin_Q(ptr), ff2->pin_Q(idx));
}
}
/* PUll the non-sliced inputs (clock, set, reset, etc)
forward to the new FF we are building. */
if (ff->pin_Aclr().is_linked())
connect(ff->pin_Aclr(), ff2->pin_Aclr());
if (ff->pin_Aset().is_linked())
@ -771,6 +821,26 @@ bool NetBlock::synth_sync(Design*des, NetScope*scope, NetFF*ff,
if (ok_flag == false)
continue;
unsigned ff2_pins_used = ff2->width();
for (unsigned idx = 0 ; idx < ff2->width() ; idx += 1) {
unsigned ptr = find_nexus_in_set(nex_map,
tmp_map->pin(idx).nexus());
if (pin_accounting[ptr].ff == ff2)
continue;
assert(ff2_pins_used > 0);
ff2_pins_used -= 1;
bool tflag = merge_ff_slices(pin_accounting[ptr].ff,
pin_accounting[ptr].pin,
ff2, idx);
if (! tflag) {
flag = false;
}
}
if (ff2_pins_used == 0)
delete ff2;
/* Use the nex_map to link up the output from the
substatement to the output of the block as a
whole. It is occasionally possible to have outputs
@ -789,13 +859,31 @@ bool NetBlock::synth_sync(Design*des, NetScope*scope, NetFF*ff,
} while (cur != last_);
/* Run through the pin accounting one more time to make sure
the data inputs are all connected. */
for (unsigned idx = 0 ; idx < ff->pin_count() ; idx += 1) {
NetFF*ff2 = pin_accounting[idx].ff;
unsigned pin = pin_accounting[idx].pin;
/* Skip this output if it is not handled in this block. */
if (ff2 == 0)
continue;
/* If this block mentioned it, then the data must have
been set here. */
if (!ff2->pin_Data(pin).is_linked()) {
cerr << ff2->get_line() << ": error: "
<< "DFF introduced here is missing Data inputs."
<< endl;
flag = false;
}
}
delete[]pin_accounting;
/* Done. The large NetFF is no longer needed, as it has been
taken up by the smaller NetFF devices. */
delete ff;
DEBUG_SYNTH2_EXIT("NetBlock",flag)
return flag;
}
@ -893,9 +981,13 @@ bool NetCondit::synth_sync(Design*des, NetScope*scope, NetFF*ff,
delete expr_input;
if (else_ == 0) {
cerr << get_line() << ": error: In this context, "
<< "synthesis requires an \"else\" clause." << endl;
return false;
/* The lack of an else_ clause here means that
there is no data input to the DFF yet
defined. This is bad, but the data input may be
given later in an enclosing block, so don't
report an error here quite yet. */
return true;
}
assert(else_ != 0);
@ -986,19 +1078,13 @@ bool NetCondit::synth_sync(Design*des, NetScope*scope, NetFF*ff,
delete a_set;
/* Failed to find an asynchronous set/reset, so any events
input are probably in error. */
if (events_in.count() > 0) {
cerr << get_line() << ": error: Events are unaccounted"
<< " for in process synthesis." << endl;
des->errors += 1;
}
input are probably in error, or simply not in use. */
/* If this is an if/then/else, then it is likely a
combinational if, and I should synthesize it that way. */
if (if_ && else_) {
bool flag = synth_async(des, scope, true, nex_map, nex_out);
DEBUG_SYNTH2_EXIT("NetCondit",flag)
return flag;
}
@ -1059,7 +1145,7 @@ bool NetEvWait::synth_sync(Design*des, NetScope*scope, NetFF*ff,
DEBUG_SYNTH2_ENTRY("NetEvWait")
if (events_in.count() > 0) {
cerr << get_line() << ": error: Events are unaccounted"
<< " for in process synthesis." << endl;
<< " for in process synthesis. (evw)" << endl;
des->errors += 1;
}
@ -1245,6 +1331,9 @@ void synth2(Design*des)
/*
* $Log: synth2.cc,v $
* Revision 1.39.2.12 2005/12/19 01:13:47 steve
* Handle DFF definitions spread out within a block.
*
* Revision 1.39.2.11 2005/12/15 02:38:51 steve
* Fix missing outputs from synchronous conditionals to get out from in.
*