adding predicate instruction

hw/rtl/VX_decode.v

@@ -349,7 +349,7 @@ module VX_decode  #(
                 ex_type = `EX_GPU;
                 case (func3)
                     3'h0: begin
-                        op_type = `OP_BITS'(`GPU_TMC);
+                        op_type = `OP_BITS'(rs2 ? `GPU_PRED : `GPU_TMC);
                         is_wstall = 1;
                         `USED_IREG (rs1);
                     end

hw/rtl/VX_define.vh

@@ -185,7 +185,7 @@
 `define GPU_SPLIT       3'h2
 `define GPU_JOIN        3'h3
 `define GPU_BAR         3'h4
-`define GPU_OTHER       3'h7
+`define GPU_PRED        3'h5
 `define GPU_BITS        3
 `define GPU_OP(x)       x[`GPU_BITS-1:0]
 

hw/rtl/VX_gpu_unit.v

@@ -19,6 +19,7 @@ module VX_gpu_unit #(
     `UNUSED_PARAM (CORE_ID)
     `UNUSED_VAR (clk)
     `UNUSED_VAR (reset)
+    `UNUSED_VAR (gpu_req_if.op_mod)
 
     gpu_tmc_t       tmc;
     gpu_wspawn_t    wspawn;
@@ -29,11 +30,18 @@ module VX_gpu_unit #(
     wire is_tmc    = (gpu_req_if.op_type == `GPU_TMC);
     wire is_split  = (gpu_req_if.op_type == `GPU_SPLIT);
     wire is_bar    = (gpu_req_if.op_type == `GPU_BAR);
+    wire is_pred   = (gpu_req_if.op_type == `GPU_PRED);
 
     // tmc
 
-    assign tmc.valid = is_tmc;
+    wire [`NUM_THREADS-1:0] pred_cond;
-    assign tmc.tmask = `NUM_THREADS'(gpu_req_if.rs1_data[gpu_req_if.tid]);
+    for (genvar i = 0; i < `NUM_THREADS; i++) begin
+        assign pred_cond[i] = gpu_req_if.tmask[i] && gpu_req_if.rs1_data[i][0];
+    end
+    wire [`NUM_THREADS-1:0] pred = (pred_cond != 0) ? pred_cond : gpu_req_if.tmask;
+
+    assign tmc.valid = is_tmc || is_pred;
+    assign tmc.tmask = is_pred ? pred : `NUM_THREADS'(gpu_req_if.rs1_data[gpu_req_if.tid]);
 
     // wspawn
 

hw/rtl/VX_print_instr.vh

@@ -128,6 +128,7 @@ task print_ex_op (
             `GPU_SPLIT: dpi_trace("SPLIT");
             `GPU_JOIN:  dpi_trace("JOIN");
             `GPU_BAR:   dpi_trace("BAR");
+            `GPU_BAR:   dpi_trace("PRED");
             default:    dpi_trace("?");
         endcase
     end    

hw/rtl/VX_warp_sched.v

@@ -74,13 +74,15 @@ module VX_warp_sched #(
             active_warps[0] <= '1;
             thread_masks[0] <= '1;
         end else begin            
-            if (warp_ctl_if.valid && warp_ctl_if.wspawn.valid) begin
+            if (warp_ctl_if.valid) begin
+                if (warp_ctl_if.wspawn.valid) begin
                     use_wspawn <= warp_ctl_if.wspawn.wmask & (~`NUM_WARPS'(1));
                     wspawn_pc  <= warp_ctl_if.wspawn.pc;
+                end else begin
+                    stalled_warps[warp_ctl_if.wid] <= 0;                        
                 end
 
-            if (warp_ctl_if.valid && warp_ctl_if.barrier.valid) begin
+                if (warp_ctl_if.barrier.valid) begin                
-                stalled_warps[warp_ctl_if.wid] <= 0;
                     if (reached_barrier_limit) begin
                         barrier_masks[warp_ctl_if.barrier.id] <= 0;
                     end else begin
@@ -88,18 +90,16 @@ module VX_warp_sched #(
                     end
                 end
                 
-            if (warp_ctl_if.valid && warp_ctl_if.tmc.valid) begin
+                if (warp_ctl_if.tmc.valid) begin
                     thread_masks[warp_ctl_if.wid] <= warp_ctl_if.tmc.tmask;
-                stalled_warps[warp_ctl_if.wid] <= 0;
                 end
                 
-            if (warp_ctl_if.valid && warp_ctl_if.split.valid) begin
+                if (warp_ctl_if.split.valid) begin
-                stalled_warps[warp_ctl_if.wid] <= 0;
                     if (warp_ctl_if.split.diverged) begin
                         thread_masks[warp_ctl_if.wid] <= warp_ctl_if.split.then_tmask;
                     end
                 end
-
+            end
 
             // Branch
             if (branch_ctl_if.valid) begin

runtime/include/vx_intrinsics.h

@@ -53,8 +53,13 @@ extern "C" {
 })
 
 // Set thread mask
-inline void vx_tmc(unsigned num_threads) {
+inline void vx_tmc(unsigned mask) {
-    asm volatile (".insn s 0x6b, 0, x0, 0(%0)" :: "r"(num_threads));
+    asm volatile (".insn s 0x6b, 0, x0, 0(%0)" :: "r"(mask));
+}
+
+// Set thread predicate
+inline void vx_pred(unsigned condition) {
+    asm volatile (".insn s 0x6b, 0, x1, 0(%0)" :: "r"(condition));
 }
 
 typedef void (*vx_wspawn_pfn)();

simX/execute.cpp

@@ -817,10 +817,21 @@ void Warp::execute(const Instr &instr, Pipeline *pipeline) {
       switch (func3) {
       case 0: {
         // TMC        
+        if (rsrc1) {
+          // predicate mode
+          ThreadMask pred;
+          for (int i = 0; i < num_threads; ++i) {
+            pred[i] = tmask_[i] ? (iRegFile_[i][rsrc0] != 0) : 0;
+          }
+          if (pred.any()) {
+            tmask_ &= pred;
+          }
+        } else {
           tmask_.reset();
           for (int i = 0; i < num_threads; ++i) {
             tmask_[i] = rsdata[0] & (1 << i);
           }
+        }
         D(3, "*** TMC " << tmask_);
         active_ = tmask_.any();
         pipeline->stall_warp = true;