From 50028baa9f2ec7f633a51a687592c195e925d5ae Mon Sep 17 00:00:00 2001
From: Stefan Frederik <stefan.schippers@gmail.com>
Date: Mon, 11 Jan 2021 19:31:47 +0100
Subject: [PATCH] added Hi-Z in logic values

---
 src/callback.c  |  4 ++--
 src/hilight.c   | 41 +++++++++++++++++++++++++++++++++++------
 src/paste.c     | 10 +++++-----
 src/save.c      |  2 +-
 src/scheduler.c |  2 +-
 5 files changed, 44 insertions(+), 15 deletions(-)

diff --git a/src/callback.c b/src/callback.c
index 886d64c6..0b50a29b 100644
--- a/src/callback.c
+++ b/src/callback.c
@@ -1102,9 +1102,9 @@ int callback(int event, int mx, int my, KeySym key,
      place_net_label(1);
      break;
    }
-   if(key >= '0' && key <= '3' && state == 0) {  /* Toggle pin logic level */
+   if(key >= '0' && key <= '4' && state == 0) {  /* Toggle pin logic level */
      if(xctx->semaphore >= 2) break;
-     if(key == '3') logic_set(-1, 1);
+     if(key == '4') logic_set(-1, 1);
      else logic_set(key - '0', 1);
      break;
    }
diff --git a/src/hilight.c b/src/hilight.c
index 22db2276..c63e0fb8 100644
--- a/src/hilight.c
+++ b/src/hilight.c
@@ -895,7 +895,7 @@ int get_logic_value(int inst, int n)
     val = 2; /* LOGIC_X */
   } else {
     val = entry->value;
-    val = (val == LOGIC_0) ? 0 : (val == LOGIC_1) ? 1 : 2;
+    val = (val == LOGIC_0) ? 0 : (val == LOGIC_1) ? 1 : (val == LOGIC_Z) ? 3 : 2;
     /* dbg(1, "get_logic_value(): inst=%d pin=%d net=%s val=%d\n", inst, n, netname, val); */
   }
   /* my_free(xxxx, &netname); */
@@ -948,6 +948,7 @@ int eval_logic_expr(int inst, int output)
         if(sp > 0) {
           sp--;
           if(!(stack[sp] & 2)) stack[sp] = !stack[sp];
+          else stack[sp] = 2;
           ++sp;
         }
         break;
@@ -961,7 +962,10 @@ int eval_logic_expr(int inst, int output)
       case 'm': /* mux operator */
         s = stack[sp - 1];
         if(sp > 2) {
-          stack[sp - 3] = (s & 2) ? 2 : (s == 0) ? stack[sp - 3]  : stack[sp - 2];
+          if(!(s & 2) ) { /* reduce pessimism, avoid infinite loops */
+            stack[sp - 3] = (s == 0) ? stack[sp - 3]  : stack[sp - 2];
+          }
+          else stack[sp - 3] = 3;
           sp -=2;
         }
         break;
@@ -1091,15 +1095,20 @@ void free_simdata(void)
   xctx->simdata.valid = 0;
 }
 
+#undef DELAYED_ASSIGN
 void propagate_logic()
 {
   /* char *propagated_net=NULL; */
-  int found /* , mult */;
+  int found, iter = 0 /* , mult */;
   int i, j, npin;
   int propagate;
+  int min_iter = 0; /* set to 3 to simulate up to 3 series bidirectional pass-devices */
   struct hilight_hashentry  *entry;
   int val, oldval, newval;
   static int map[] = {LOGIC_0, LOGIC_1, LOGIC_X, LOGIC_Z};
+  #ifdef DELAYED_ASSIGN
+  int *newval_arr = NULL;
+  #endif
 
   tclsetvar("tclstop", "0");
   prepare_netlist_structs(0);
@@ -1107,6 +1116,10 @@ void propagate_logic()
     found=0;
     for(i=0; i<xctx->simdata.ninst; i++) {
       npin = xctx->simdata.inst[i].npin;
+      #ifdef DELAYED_ASSIGN
+      my_realloc(778, &newval_arr, npin * sizeof(int));
+      for(j=0; j<npin;j++) newval_arr[j] = -10000;
+      #endif
       for(j=0; j<npin;j++) {
         if(xctx->simdata.inst && xctx->simdata.inst[i].pin && xctx->simdata.inst[i].pin[j].go_to) {
           int n = 1;
@@ -1162,20 +1175,36 @@ void propagate_logic()
             oldval = (!entry) ? LOGIC_X : entry->value;
             newval = eval_logic_expr(i, propagate);
             val =  map[newval];
-            if(newval != 3 && oldval != val) {
-               hilight_lookup(xctx->inst[i].node[propagate], val, XINSERT);
-               if(newval!=3) found=1; /* keep looping until no more nets are found. */
+            if(iter < min_iter || (newval != 3 && oldval != val) ) {
+              dbg(1, "propagate_logic(): inst %d pin %d oldval %d newval %d to pin %s\n",
+                   i, j, oldval, val, xctx->inst[i].node[propagate]);
+
+              #ifdef DELAYED_ASSIGN
+              newval_arr[propagate] = val;
+              #else 
+              hilight_lookup(xctx->inst[i].node[propagate], val, XINSERT);
+              #endif
+              found=1; /* keep looping until no more nets are found. */
             }
           }
         }
       } /* for(j...) */
+      #ifdef DELAYED_ASSIGN
+      for(j=0;j<npin;j++) {
+        if(newval_arr[j] != -10000) hilight_lookup(xctx->inst[i].node[j], newval_arr[j], XINSERT);
+      }
+      #endif
     } /* for(i...) */
     xctx->hilight_time++;
     if(!found) break;
     /* get out from infinite loops (circuit is oscillating) */
     Tcl_VarEval(interp, "update; if {$::tclstop == 1} {return 1} else {return 0}", NULL);
     if( tclresult()[0] == '1') break;
+    iter++;
   } /* while(1) */
+  #ifdef DELAYED_ASSIGN
+  my_free(779, &newval_arr);
+  #endif
   /* my_free(1222, &propagated_net); */
 }
 
diff --git a/src/paste.c b/src/paste.c
index f991cc2a..7df2dd36 100644
--- a/src/paste.c
+++ b/src/paste.c
@@ -182,9 +182,9 @@ void merge_polygon(FILE *fd)
     for(j=0;j<points;j++) {
       if(fscanf(fd, "%lf %lf ",&(ptr[i].x[j]), &(ptr[i].y[j]))<2) {
         fprintf(errfp,"merge_polygon(): WARNING: missing fields for POLYGON points, ignoring.\n");
-        my_free(886, &ptr[i].x);
-        my_free(887, &ptr[i].y);
-        my_free(888, &ptr[i].selected_point);
+        my_free(827, &ptr[i].x);
+        my_free(1218, &ptr[i].y);
+        my_free(1223, &ptr[i].selected_point);
         read_line(fd, 0);
         return;
       }
@@ -244,10 +244,10 @@ void merge_inst(int k,FILE *fd)
     load_ascii_string(&tmp, fd);
     /* avoid as much as possible calls to rel_sym_path (slow) */
     #ifdef __unix__
-    if(tmp[0] == '/') my_strdup(755, &ptr[i].name, rel_sym_path(tmp));
+    if(tmp[0] == '/') my_strdup(763, &ptr[i].name, rel_sym_path(tmp));
     else my_strdup(755, &ptr[i].name,tmp);
     #else
-    my_strdup(755, &ptr[i].name, rel_sym_path(tmp));
+    my_strdup(780, &ptr[i].name, rel_sym_path(tmp));
     #endif
     my_free(756, &tmp);
     if(fscanf(fd, "%lf %lf %hd %hd",&ptr[i].x0, &ptr[i].y0,&ptr[i].rot, &ptr[i].flip) < 4) {
diff --git a/src/save.c b/src/save.c
index 7f3f0014..6ea0b07b 100644
--- a/src/save.c
+++ b/src/save.c
@@ -543,7 +543,7 @@ static void load_inst(int k, FILE *fd)
     if(name[0] == '/') my_strdup2(56, &xctx->inst[i].name, rel_sym_path(name));
     else my_strdup2(762, &xctx->inst[i].name, name);
     #else 
-    my_strdup2(56, &xctx->inst[i].name, rel_sym_path(name));
+    my_strdup2(777, &xctx->inst[i].name, rel_sym_path(name));
     #endif
     if(fscanf(fd, "%lf %lf %hd %hd", &xctx->inst[i].x0, &xctx->inst[i].y0,
        &xctx->inst[i].rot, &xctx->inst[i].flip) < 4) {
diff --git a/src/scheduler.c b/src/scheduler.c
index bde68928..3f12987c 100644
--- a/src/scheduler.c
+++ b/src/scheduler.c
@@ -1451,7 +1451,7 @@ int xschem(ClientData clientdata, Tcl_Interp *interp, int argc, const char * arg
       if(argc > 3 ) num = atoi(argv[3]);
       if(argc > 2) {
         int n = atoi(argv[2]);
-        if(n == 3) n = -1;
+        if(n == 4) n = -1;
         logic_set(n, num);
       }
       Tcl_ResetResult(interp);