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Generate constant drivers as concurrent assignments

This commit is contained in:
Nick Gasson 2008-07-29 14:02:05 +01:00
parent f8034d69ef
commit a842b327c7
2 changed files with 63 additions and 32 deletions
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6
tgt-vhdl/expr.cc
View File

@ -55,12 +55,6 @@ static vhdl_expr *translate_string(ivl_expr_t e)
static vhdl_var_ref *translate_signal(ivl_expr_t e)
{
ivl_signal_t sig = ivl_expr_signal(e);
// Make sure the nexus code is generated
for (unsigned i = ivl_signal_array_base(sig);
i < ivl_signal_array_count(sig);
i++)
seen_nexus(ivl_signal_nex(sig, i));
const vhdl_scope *scope = find_scope_for_signal(sig);
assert(scope);

89
tgt-vhdl/scope.cc
View File

@ -136,6 +136,7 @@ struct nexus_private_t {
};
list<scope_signal_map_t> signals;
vhdl_expr *const_driver;
};
/*
@ -168,6 +169,7 @@ static ivl_signal_t visible_nexus_signal(nexus_private_t *priv, vhdl_scope *scop
void draw_nexus(ivl_nexus_t nexus)
{
nexus_private_t *priv = new nexus_private_t;
priv->const_driver = NULL;
int nptrs = ivl_nexus_ptrs(nexus);
@ -234,32 +236,13 @@ void draw_nexus(ivl_nexus_t nexus)
}
else if ((con = ivl_nexus_ptr_con(nexus_ptr))) {
cout << "CONSTANT" << endl;
list<nexus_private_t::scope_signal_map_t>::iterator it;
for (it = priv->signals.begin(); it != priv->signals.end(); ++it) {
cout << "...linked to signal " << ivl_signal_name((*it).sig) << endl;
// Make this the initial value of the signal
const string &renamed = get_renamed_signal((*it).sig);
vhdl_decl *decl =
find_scope_for_signal((*it).sig)->get_decl(renamed);
assert(decl);
if (!decl->has_initial()) {
if (ivl_const_width(con) == 1)
decl->set_initial
(new vhdl_const_bit(ivl_const_bits(con)[0]));
else
decl->set_initial
(new vhdl_const_bits(ivl_const_bits(con),
ivl_const_width(con),
ivl_const_signed(con) != 0));
}
else {
error("signal %s has two constant drivers!?", renamed.c_str());
assert(false);
}
}
if (ivl_const_width(con) == 1)
priv->const_driver = new vhdl_const_bit(ivl_const_bits(con)[0]);
else
priv->const_driver =
new vhdl_const_bits(ivl_const_bits(con), ivl_const_width(con),
ivl_const_signed(con) != 0);
}
}
@ -791,6 +774,56 @@ static int draw_all_signals(ivl_scope_t scope, void *_parent)
return ivl_scope_children(scope, draw_all_signals, scope);
}
/*
* Make concurrent assignments for constants in nets. This works
* bottom-up so that the driver is in the lowest instance it can.
* This also has the side effect of generating all the necessary
* nexus code.
*/
static int draw_constant_drivers(ivl_scope_t scope, void *_parent)
{
ivl_scope_children(scope, draw_constant_drivers, scope);
if (ivl_scope_type(scope) == IVL_SCT_MODULE) {
vhdl_entity *ent = find_entity(ivl_scope_tname(scope));
assert(ent);
if (ent->get_derived_from() == ivl_scope_name(scope)) {
int nsigs = ivl_scope_sigs(scope);
for (int i = 0; i < nsigs; i++) {
ivl_signal_t sig = ivl_scope_sig(scope, i);
for (unsigned i = ivl_signal_array_base(sig);
i < ivl_signal_array_count(sig);
i++) {
// Make sure the nexus code is generated
ivl_nexus_t nex = ivl_signal_nex(sig, i);
seen_nexus(nex);
assert(i == 0); // TODO: Make work for more words
nexus_private_t *priv =
static_cast<nexus_private_t*>(ivl_nexus_get_private(nex));
assert(priv);
if (priv->const_driver) {
cout << "NEEDS CONST DRIVER!" << endl;
cout << "(in scope " << ivl_scope_name(scope) << endl;
vhdl_var_ref *ref =
nexus_to_var_ref(ent->get_arch()->get_scope(), nex);
ent->get_arch()->add_stmt
(new vhdl_cassign_stmt(ref, priv->const_driver));
priv->const_driver = NULL;
}
}
}
}
}
return 0;
}
static int draw_all_logic_and_lpm(ivl_scope_t scope, void *_parent)
{
if (ivl_scope_type(scope) == IVL_SCT_MODULE) {
@ -876,6 +909,10 @@ int draw_scope(ivl_scope_t scope, void *_parent)
rc = draw_hierarchy(scope, _parent);
if (rc != 0)
return rc;
rc = draw_constant_drivers(scope, _parent);
if (rc != 0)
return rc;
return 0;
}