diff --git a/hw/rtl/VX_ipdom_stack.sv b/hw/rtl/VX_ipdom_stack.sv
index 4cdb1317..2c0cc322 100644
--- a/hw/rtl/VX_ipdom_stack.sv
+++ b/hw/rtl/VX_ipdom_stack.sv
@@ -6,11 +6,13 @@ module VX_ipdom_stack #(
 ) (
     input  wire               clk,
     input  wire               reset,
+    input  wire               pair,
     input  wire [WIDTH - 1:0] q1,
     input  wire [WIDTH - 1:0] q2,
     output wire [WIDTH - 1:0] d,
     input  wire               push,
     input  wire               pop,
+    output wire               index,
     output wire               empty,
     output wire               full
 );
@@ -52,15 +54,15 @@ module VX_ipdom_stack #(
     
     always @(posedge clk) begin
         if (push) begin
-            is_part[wr_ptr] <= 0;   
+            is_part[wr_ptr] <= ~pair;   
         end else if (pop) begin            
             is_part[rd_ptr] <= 1;
         end
     end
-    wire p = is_part[rd_ptr];
 
-    assign d     = p ? d1 : d2;
-    assign empty = ~(| wr_ptr);
+    assign index = is_part[rd_ptr];
+    assign d     = index ? d1 : d2;
+    assign empty = (ADDRW'(0) == wr_ptr);
     assign full  = (ADDRW'(DEPTH-1) == wr_ptr);
 
 endmodule
\ No newline at end of file
diff --git a/hw/rtl/VX_warp_sched.sv b/hw/rtl/VX_warp_sched.sv
index e206c09e..9495c001 100644
--- a/hw/rtl/VX_warp_sched.sv
+++ b/hw/rtl/VX_warp_sched.sv
@@ -24,7 +24,7 @@ module VX_warp_sched #(
 
     wire                    join_else;
     wire [31:0]             join_pc;
-    wire [`NUM_THREADS-1:0] join_tm;
+    wire [`NUM_THREADS-1:0] join_tmask;
 
     reg [`NUM_WARPS-1:0] active_warps, active_warps_n;   // real active warps (updated when a warp is activated or disabled)
     reg [`NUM_WARPS-1:0] stalled_warps;  // asserted when a branch/gpgpu instructions are issued
@@ -132,7 +132,7 @@ module VX_warp_sched #(
                 if (join_else) begin
                     warp_pcs[join_if.wid] <= join_pc;
                 end
-                thread_masks[join_if.wid] <= join_tm;
+                thread_masks[join_if.wid] <= join_tmask;
             end
 
             active_warps <= active_warps_n;
@@ -162,9 +162,8 @@ module VX_warp_sched #(
 
     // split/join stack management    
 
-    wire [(1+32+`NUM_THREADS)-1:0] ipdom [`NUM_WARPS-1:0];
-
-    wire [`NUM_THREADS-1:0] curr_tmask = thread_masks[warp_ctl_if.wid];
+    wire [(32+`NUM_THREADS)-1:0] ipdom_data [`NUM_WARPS-1:0]; 
+    wire ipdom_index [`NUM_WARPS-1:0];   
     
     for (genvar i = 0; i < `NUM_WARPS; i++) begin
         wire push = warp_ctl_if.valid 
@@ -173,27 +172,32 @@ module VX_warp_sched #(
 
         wire pop = join_if.valid && (i == join_if.wid);
 
-        wire [`NUM_THREADS-1:0] else_tmask = warp_ctl_if.split.diverged ? warp_ctl_if.split.else_tmask : curr_tmask;
-        wire [(1+32+`NUM_THREADS)-1:0] q_end  = {1'b0, 32'b0,                curr_tmask};
-        wire [(1+32+`NUM_THREADS)-1:0] q_else = {1'b1, warp_ctl_if.split.pc, else_tmask};
+        wire [`NUM_THREADS-1:0] else_tmask = warp_ctl_if.split.else_tmask;
+        wire [`NUM_THREADS-1:0] orig_tmask = thread_masks[warp_ctl_if.wid];
+
+        wire [(32+`NUM_THREADS)-1:0] q_else = {warp_ctl_if.split.pc, else_tmask};
+        wire [(32+`NUM_THREADS)-1:0] q_end  = {32'b0,                orig_tmask};
 
         VX_ipdom_stack #(
-            .WIDTH (1+32+`NUM_THREADS), 
+            .WIDTH (32+`NUM_THREADS), 
             .DEPTH (2 ** (`NT_BITS+1))
         ) ipdom_stack (
             .clk   (clk),
             .reset (reset),
             .push  (push),
             .pop   (pop),
+            .pair  (warp_ctl_if.split.diverged),
             .q1    (q_end),
             .q2    (q_else),
-            .d     (ipdom[i]),
+            .d     (ipdom_data[i]),
+            .index (ipdom_index[i]),
             `UNUSED_PIN (empty),
             `UNUSED_PIN (full)
         );
     end
 
-    assign {join_else, join_pc, join_tm} = ipdom [join_if.wid];
+    assign {join_pc, join_tmask} = ipdom_data[join_if.wid];
+    assign join_else = ~ipdom_index[join_if.wid];
 
     // schedule the next ready warp