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Try to eliminate excessive processing recursions. 

After calculating the A side of a tran[if/vp], the B side is usually
fully specified, so make an effort to push the calculated value through.
This commit is contained in:
Stephen Williams 2008-06-04 16:10:43 -07:00
parent e872310e4b
commit e97a1ad610
1 changed files with 77 additions and 24 deletions
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101
vvp/vvp_island.cc
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@ -484,34 +484,81 @@ static void resolve_values_from_connections(vvp_vector8_t&val,
}
}
static void push_value_through_branches(const vvp_vector8_t&val,
list<vvp_branch_ptr_t>&connections)
{
for (list<vvp_branch_ptr_t>::iterator idx = connections.begin()
; idx != connections.end() ; idx ++ ) {
vvp_island_branch*tmp_ptr = idx->ptr();
unsigned tmp_ab = idx->port();
unsigned other_ab = tmp_ab^1;
// If other side already done, skip
if (tmp_ptr->flags & (1<<other_ab))
continue;
// If link is not enabled, skip.
if (! tmp_ptr->enabled_flag)
continue;
vvp_net_t*other_net = other_ab? tmp_ptr->b : tmp_ptr->a;
if (tmp_ptr->width == 0) {
// Mark this end as done
tmp_ptr->flags |= (1 << other_ab);
vvp_send_vec8(other_net->out, val);
} if (other_ab == 1) {
// Mark as done
tmp_ptr->flags |= (1 << other_ab);
vvp_vector8_t tmp = val.subvalue(tmp_ptr->offset, tmp_ptr->part);
vvp_send_vec8(other_net->out, tmp);
} else {
// Otherwise, the other side is not fully
// specified, so we can't take this shortcut.
}
}
}
void vvp_island_branch::run_resolution()
{
// Collect all the branch endpoints that are joined to my A
// side.
list<vvp_branch_ptr_t> connections;
collect_node(connections, vvp_branch_ptr_t(this, 0));
bool processed_a_side = false;
vvp_vector8_t val;
// Mark my A side as done. Do this early to prevent recursing
// back. All the connections that share this port are also
// done. Make sure their flags are set appropriately.
mark_done_flags(connections);
if ((flags & 1) == 0) {
processed_a_side = true;
collect_node(connections, vvp_branch_ptr_t(this, 0));
vvp_vector8_t val = get_value(a);
mark_visited_flags(connections); // Mark as visited.
// Mark my A side as done. Do this early to prevent recursing
// back. All the connections that share this port are also
// done. Make sure their flags are set appropriately.
mark_done_flags(connections);
// Now scan the other sides of all the branches connected to
// my A side. The get_value_from_branch() will recurse as
// necessary to depth-first walk the graph.
resolve_values_from_connections(val, connections);
val = get_value(a);
mark_visited_flags(connections); // Mark as visited.
// A side is done.
vvp_send_vec8(a->out, val);
// Now scan the other sides of all the branches connected to
// my A side. The get_value_from_branch() will recurse as
// necessary to depth-first walk the graph.
resolve_values_from_connections(val, connections);
// Clear the visited flags. This must be done so that other
// branches can read this input value.
clear_visited_flags(connections);
// A side is done.
vvp_send_vec8(a->out, val);
// Clear the visited flags. This must be done so that other
// branches can read this input value.
clear_visited_flags(connections);
push_value_through_branches(val, connections);
}
// Repeat the above for the B side.
if (flags & 2)
return;
connections.clear();
collect_node(connections, vvp_branch_ptr_t(this, 1));
@ -519,16 +566,22 @@ void vvp_island_branch::run_resolution()
// If this is a connected branch without a part select, then
// we know from the start that the B side has the same
// value as this. Mark it and finish.
if (enabled_flag && width==0) {
vvp_send_vec8(b->out, val);
return;
// value as this. Even if the B side is a part select, the
// simple part select must be correct because the recursive
// resolve_values_from_connections above must of cycled back
// to the B side of myself when resolving the connections.
if (enabled_flag && processed_a_side) {
if (width != 0)
val = val.subvalue(offset, part);
} else {
val = get_value(b);
mark_visited_flags(connections);
resolve_values_from_connections(val, connections);
clear_visited_flags(connections);
}
val = get_value(b);
mark_visited_flags(connections);
resolve_values_from_connections(val, connections);
clear_visited_flags(connections);
vvp_send_vec8(b->out, val);
}