tensor: Test many-commit per execute with an FSM

Trick is to set commit_if.data.eop to 0, since the commit module only
signals instruction completion to VX_schedule if the eop bit is 1.
Otherwise it underflows the pending_instr buffer.

The same eop trick works for VX_scoreboard, which works around the
invalid rd writeback error.

hw/rtl/core/VX_tensor_hopper_core.sv

@@ -11,7 +11,7 @@ module VX_tensor_hopper_core_block import VX_gpu_pkg::*; #(
     VX_execute_if.slave execute_if,
     VX_commit_if.master commit_if
 );
-    localparam METADATA_QUEUE_DEPTH = 2; // FIXME: arbitrary
+    localparam METADATA_QUEUE_DEPTH = 16; // FIXME: arbitrary
 
     /* commit_if.data_t parts that we need to keep around:
         - uuid
@@ -37,6 +37,7 @@ module VX_tensor_hopper_core_block import VX_gpu_pkg::*; #(
     };
 
     wire [`NUM_WARPS-1:0][DATAW-1:0] execute_if_data_deq;
+    logic [DATAW-1:0] execute_if_data_new_rd;
 
     wire [`NUM_WARPS-1:0] metadata_queue_fulls;
     wire [`NUM_WARPS-1:0] metadata_queue_emptys;
@@ -47,6 +48,8 @@ module VX_tensor_hopper_core_block import VX_gpu_pkg::*; #(
     `RUNTIME_ASSERT((!execute_if.valid || execute_if.data.wid == `NW_WIDTH'(0)),
         ("runtime error: WGMMA execute not supported for warps other than 0!"))
 
+    logic metadata_deq;
+
     for (genvar i = 0; i < `NUM_WARPS; i++) begin
         // Metadata queue for commit_if.  This simply copies execute_if's
         // metadata and pops them in conjunction with commit fire.
@@ -58,7 +61,7 @@ module VX_tensor_hopper_core_block import VX_gpu_pkg::*; #(
 
         wire enq = operand_enq_fire && (execute_if.data.wid == `NW_WIDTH'(i));
         // FIXME: commit only warp 0
-        wire deq =   commit_if_fire && (`NW_WIDTH'(i) == `NW_WIDTH'(0));
+        wire deq = metadata_deq && commit_if.ready && (`NW_WIDTH'(i) == `NW_WIDTH'(0));
 
         VX_fifo_queue #(
             .DATAW(DATAW),
@@ -82,18 +85,58 @@ module VX_tensor_hopper_core_block import VX_gpu_pkg::*; #(
     // the commit stage
     `RUNTIME_ASSERT(!(!reset && metadata_queue_full), ("tensor core uop queue is full!"))
 
-    // FIXME: only checks warp 0 for commit!
+    // dummy FSM that generates commits
-    assign commit_if.valid = ~metadata_queue_emptys[0/*FIXME*/];
+    logic [1:0] state, state_n;
+    localparam STATE_IDLE = 4'd0;
+
+    always @(*) begin
+        state_n = state;
+        metadata_deq = 1'b0;
+
+        // when incremented to 1, count up until wrap-around to 0
+        if (state != STATE_IDLE) begin
+            state_n = state + 1'd1;
+        end else begin
+            // kick-off from idle when execute valid
+            // FIXME: only checks warp 0 for commit!
+            if (~metadata_queue_emptys[0/*FIXME*/]) begin
+                state_n = 4'd1;
+            end
+        end
+
+        // dequeue metadata when wrapping around
+        if ((state != STATE_IDLE) && (state_n == STATE_IDLE)) begin
+            metadata_deq = 1'b1;
+        end
+
+        // change rd of the commit data according to state
+        execute_if_data_new_rd =
+            {execute_if_data_deq[0/*FIXME*/][DATAW-1:`NR_BITS],
+             (`NR_BITS'(`NUM_IREGS) + `NR_BITS'(state))};
+    end
+
+    always @(posedge clk) begin
+        if (reset) begin
+            state <= '0;
+        end else begin
+            state <= state_n;
+        end
+    end
+
+    // assign commit_if.valid = metadata_deq;
+    assign commit_if.valid = (state != STATE_IDLE);
 
     wire [`NUM_THREADS-1:0][`XLEN-1:0] wb_data = '0;
 
     localparam COMMIT_DATAW = `UUID_WIDTH + `NW_WIDTH + `NUM_THREADS + `XLEN + 1 + `NR_BITS + (`NUM_THREADS * `XLEN) + 1 + 1 + 1;
     wire [COMMIT_DATAW-1:0] commit_if_data = {
-        execute_if_data_deq[0/*FIXME*/], /* uuid ~ rd */
+        // write-back to the correct rd only when eop
+        ((state == 2'b11) ? execute_if_data_deq[0/*FIXME*/] : execute_if_data_new_rd), /* uuid ~ rd */
         wb_data, /* data */
         1'b0, /* pid */
         1'b1, /* sop */
-        1'b1  /* eop */
+        (state == 2'b11)  /* eop */
+        // 1'b1  /* eop */
     };
 
     assign commit_if.data = commit_if_data;