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Generate code that causes the value of a net to be passed 

passed through all nets of a nexus.
This commit is contained in:
steve 2001-05-06 00:01:02 +00:00
parent de5930f7d8
commit 558fea33fb
1 changed files with 128 additions and 16 deletions
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144
tgt-vvp/vvp_scope.c
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@ -17,12 +17,13 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
#if !defined(WINNT)
#ident "$Id: vvp_scope.c,v 1.24 2001/05/03 04:55:46 steve Exp $"
#ident "$Id: vvp_scope.c,v 1.25 2001/05/06 00:01:02 steve Exp $"
#endif
# include "vvp_priv.h"
# include <assert.h>
# include <malloc.h>
# include <string.h>
/*
* The draw_scope function draws the major functional items within a
@ -30,14 +31,36 @@
* other functions in this file are in support of that task.
*/
/*
* NEXUS
* ivl builds up the netlist into objects connected together by
* ivl_nexus_t objects. The nexus receives all the drivers of the
* point in the net and resolves the value. The result is then sent to
* all the nets that are connected to the nexus. The nets, then, are
* read to get the value of the nexus.
*
* NETS
* Nets are interesting and special, because a nexus may be connected
* to several of them at once. This can happen, for example, as an
* artifact of module port connects, where the inside and the outside
* of the module are connected through an in-out port. (In fact, ivl
* will simply connect signals that are bound through a port, because
* the input/output/inout properties are enforced as compile time.)
*
* This case is handled by choosing one to receive the value of the
* nexus. This one then feeds to another net at the nexus, and so
* on. The last net is selected as the output of the nexus.
*/
/*
* This function takes a nexus and looks for an input functor. It then
* draws to the output a string that represents that functor.
* draws to the output a string that represents that functor. What we
* are trying to do here is find the input to the net that is attached
* to this nexus.
*
* XXXX This function does not yet support multiple drivers.
*/
void draw_nexus_input(ivl_nexus_t nex)
void draw_net_input(ivl_nexus_t nex)
{
ivl_net_const_t cptr;
ivl_net_logic_t lptr;
@ -54,7 +77,7 @@ void draw_nexus_input(ivl_nexus_t nex)
lptr = ivl_nexus_ptr_log(nptr);
if (lptr && (ivl_logic_type(lptr) == IVL_LO_BUFZ) &&
(nptr_pin == 0)) {
draw_nexus_input(ivl_logic_pin(lptr, 1));
draw_net_input(ivl_logic_pin(lptr, 1));
assert(driver == 0);
driver = nptr;
@ -122,6 +145,42 @@ void draw_nexus_input(ivl_nexus_t nex)
}
}
/*
* This function looks at the nexus in search for the net to attach
* functor inputs to. Sort the signals in the nexus by name, and
* choose the lexically earliest one.
*/
void draw_input_from_net(ivl_nexus_t nex)
{
unsigned idx;
ivl_signal_t sig = 0;
unsigned sig_pin = 0;
for (idx = 0 ; idx < ivl_nexus_ptrs(nex) ; idx += 1) {
ivl_nexus_ptr_t ptr = ivl_nexus_ptr(nex, idx);
ivl_signal_t tmp = ivl_nexus_ptr_sig(ptr);
if (tmp == 0)
continue;
if (sig == 0) {
sig = tmp;
sig_pin = ivl_nexus_ptr_pin(ptr);
continue;
}
if (strcmp(ivl_signal_name(tmp),ivl_signal_name(sig)) < 0) {
sig = tmp;
sig_pin = ivl_nexus_ptr_pin(ptr);
continue;
}
}
assert(sig);
fprintf(vvp_out, "V_%s[%u]", ivl_signal_name(sig), sig_pin);
}
/*
* This function draws a reg/int/variable in the scope. This is a very
* simple device to draw as there are no inputs to connect so no need
@ -139,6 +198,44 @@ static void draw_reg_in_scope(ivl_signal_t sig)
ivl_signal_basename(sig), msb, lsb);
}
/*
* This function takes a nexus and a signal, and finds the next signal
* (lexically) that is connected to at the same nexus. Return the
* ivl_nexus_ptr_t object to represent that junction.
*/
static ivl_nexus_ptr_t find_net_just_after(ivl_nexus_t nex,
ivl_signal_t sig)
{
ivl_nexus_ptr_t res = 0;
ivl_signal_t res_sig = 0;
unsigned idx;
for (idx = 0 ; idx < ivl_nexus_ptrs(nex) ; idx += 1) {
ivl_nexus_ptr_t ptr = ivl_nexus_ptr(nex, idx);
ivl_signal_t tmp = ivl_nexus_ptr_sig(ptr);
if (tmp == 0)
continue;
if (strcmp(ivl_signal_name(tmp),ivl_signal_name(sig)) <= 0)
continue;
if (res == 0) {
res = ptr;
res_sig = tmp;
continue;
}
if (strcmp(ivl_signal_name(tmp),ivl_signal_name(res_sig)) < 0) {
res = ptr;
res_sig = tmp;
}
}
return res;
}
/*
* This function draws a net. This is a bit more complicated as we
* have to find an appropriate functor to connect to the input.
@ -155,10 +252,21 @@ static void draw_net_in_scope(ivl_signal_t sig)
ivl_signal_name(sig), signed_flag,
ivl_signal_basename(sig), msb, lsb);
/* Connect all the pins of the signal to something. */
for (idx = 0 ; idx < ivl_signal_pins(sig) ; idx += 1) {
ivl_nexus_ptr_t ptr;
ivl_nexus_t nex = ivl_signal_pin(sig, idx);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
ptr = find_net_just_after(nex, sig);
if (ptr) {
fprintf(vvp_out, "V_%s[%u]",
ivl_signal_name(ivl_nexus_ptr_sig(ptr)),
ivl_nexus_ptr_pin(ptr));
} else {
draw_net_input(nex);
}
}
fprintf(vvp_out, ";\n");
@ -231,7 +339,7 @@ static void draw_udp_in_scope(ivl_net_logic_t lptr)
{
ivl_nexus_t nex = ivl_logic_pin(lptr, pdx);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
fprintf(vvp_out, ";\n");
@ -318,7 +426,7 @@ static void draw_logic_in_scope(ivl_net_logic_t lptr)
for (pdx = 1 ; pdx < ivl_logic_pins(lptr) ; pdx += 1) {
ivl_nexus_t nex = ivl_logic_pin(lptr, pdx);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
for ( ; pdx < 5 ; pdx += 1) {
@ -368,7 +476,7 @@ static void draw_event_in_scope(ivl_event_t obj)
for (sub = idx ; sub < top ; sub += 1) {
ivl_nexus_t nex = ivl_event_any(obj, sub);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
fprintf(vvp_out, ";\n");
}
@ -385,7 +493,7 @@ static void draw_event_in_scope(ivl_event_t obj)
for (sub = idx ; sub < top ; sub += 1) {
ivl_nexus_t nex = ivl_event_neg(obj, sub);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
fprintf(vvp_out, ";\n");
}
@ -402,7 +510,7 @@ static void draw_event_in_scope(ivl_event_t obj)
for (sub = idx ; sub < top ; sub += 1) {
ivl_nexus_t nex = ivl_event_pos(obj, sub);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
fprintf(vvp_out, ";\n");
}
@ -431,7 +539,7 @@ static void draw_event_in_scope(ivl_event_t obj)
for (idx = 0 ; idx < nany ; idx += 1) {
ivl_nexus_t nex = ivl_event_any(obj, idx);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
} else if (nneg > 0) {
@ -441,7 +549,7 @@ static void draw_event_in_scope(ivl_event_t obj)
for (idx = 0 ; idx < nneg ; idx += 1) {
ivl_nexus_t nex = ivl_event_neg(obj, idx);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
} else {
@ -451,7 +559,7 @@ static void draw_event_in_scope(ivl_event_t obj)
for (idx = 0 ; idx < npos ; idx += 1) {
ivl_nexus_t nex = ivl_event_pos(obj, idx);
fprintf(vvp_out, ", ");
draw_nexus_input(nex);
draw_input_from_net(nex);
}
}
@ -476,11 +584,11 @@ static void draw_lpm_mux(ivl_lpm_t net)
ivl_nexus_t b = ivl_lpm_data2(net, 1, idx);
fprintf(vvp_out, "L_%s/%u .functor MUXZ, ",
ivl_lpm_name(net), idx);
draw_nexus_input(a);
draw_input_from_net(a);
fprintf(vvp_out, ", ");
draw_nexus_input(b);
draw_input_from_net(b);
fprintf(vvp_out, ", ");
draw_nexus_input(s);
draw_input_from_net(s);
fprintf(vvp_out, ", C<1>;\n");
}
@ -560,6 +668,10 @@ int draw_scope(ivl_scope_t net, ivl_scope_t parent)
/*
* $Log: vvp_scope.c,v $
* Revision 1.25 2001/05/06 00:01:02 steve
* Generate code that causes the value of a net to be passed
* passed through all nets of a nexus.
*
* Revision 1.24 2001/05/03 04:55:46 steve
* Generate code for the fully general event or.
*