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verilog-to-routing · May 12, 2023 · 76bb293 · 76bb293
1 parent 188cfb5
commit 76bb293
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Showing 2 changed files with 17 additions and 17 deletions.
diff --git a/odin_ii/src/core/subtractions.cpp b/odin_ii/src/core/subtractions.cpp
@@ -451,13 +451,13 @@ void split_adder_for_sub(nnode_t* nodeo, int a, int b, int sizea, int sizeb, int
             }
         }
 
-        for (i = offset; i < count; i++) {
+        for (i = offset; i < count - 1; i++) {
             num = (b + 1) - i * sizeb;
             if (num > sizeb)
                 num = sizeb;
 
             for (j = 0; j < num; j++) {
-                if (i == count - 1 && flag == 1) {
+                if (i == count - 2 && flag == 1) {
                     /* If the input pin of not gate connects to gnd, replacing the input pin and the not gate with vcc;
                      * if the input pin of not gate connects to vcc, replacing the input pin and the not gate with gnd.*/
                     /* connecting untouched nets in the netlist creation to the pad node */
@@ -501,8 +501,8 @@ void split_adder_for_sub(nnode_t* nodeo, int a, int b, int sizea, int sizeb, int
     }
 
     if ((flag == 0 || count > 1) && !configuration.adder_cin_global) {
-        //connect the a[0] of first adder node to ground, and b[0] of first adder node to vcc
-        connect_nodes(netlist->gnd_node, 0, node[0], 0);
+        //connect the a[0] of first adder node to vcc, and b[0] of first adder node to vcc
+        connect_nodes(netlist->vcc_node, 0, node[0], 0);
         connect_nodes(netlist->vcc_node, 0, node[0], sizea);
         //hang the first sumout
         node[0]->output_pins[1] = allocate_npin();
@@ -573,6 +573,8 @@ void split_adder_for_sub(nnode_t* nodeo, int a, int b, int sizea, int sizeb, int
     // Pad outputs with a unique and descriptive name to avoid collisions.
     node[count - 1]->output_pins[0]->name = append_string("", "%s~dummy_output~%d~%d", node[(count - 1)]->name, (count - 1), 0);
     //connect_nodes(node[count - 1], (node[(count - 1)]->num_output_pins - 1), netlist->gnd_node, 0);
+    connect_nodes(netlist->vcc_node, 0, node[count - 1], 0);
+    connect_nodes(netlist->gnd_node, 0, node[count - 1], sizea);
     //}
 
     /* Freeing the old node! */
@@ -626,17 +628,15 @@ void iterate_adders_for_sub(netlist_t* netlist) {
                 b = node->input_port_sizes[0];
             num = (a >= b) ? a : b;
 
-            if (num >= min_threshold_adder) {
-                // how many subtractors base on a can split
-                if ((a + 1) % sizea == 0)
-                    counta = (a + offset) / sizea;
-                else
-                    counta = (a + 1) / sizea + 1;
-                // how many subtractors base on b can split
-                if ((b + 1) % sizeb == 0)
-                    countb = (b + offset) / sizeb;
-                else
-                    countb = (b + 1) / sizeb + 1;
+            if (num >= min_threshold_adder && num >= min_add) {
+                // if the first cin in a chain is fed by a global input (offset = 0) the adder width is the
+                // input width + 1 (to pass the last cout -> sumout) divided by size of the adder input ports
+                // otherwise (offset = 1) a dummy adder is added to the chain to feed the first cin with gnd
+                // how many adders a can split
+                counta = (a + 1) / sizea + offset;
+                // how many adders b can split
+                countb = (b + 1) / sizeb + offset;
+                // how many adders need to be split
                 // how many subtractors need to be split
                 if (counta >= countb)
                     count = counta;

diff --git a/odin_ii/src/netlist/netlist_create_from_ast.cpp b/odin_ii/src/netlist/netlist_create_from_ast.cpp
@@ -3599,8 +3599,8 @@ signal_list_t* create_operation_node(ast_node_t* op, signal_list_t** input_lists
             break;
         case MINUS: // -
             /* subtract the largest bit width + the other input padded with 0's ... concern for 2's comp */
-            output_port_width = max_input_port_width;
-            input_port_width = output_port_width;
+            output_port_width = max_input_port_width + 1;
+            input_port_width = max_input_port_width;
             sub_list = insert_in_vptr_list(sub_list, operation_node);
 
             break;