Add dummy code for decoupled Hopper tensor core

Define EXT_T_HOPPER that, when EXT_T_ENABLE is defined, distinguishes
whether to instantiate core-coupled Volta-style or decoupled
Hopper-style Tensor Core.

hw/rtl/VX_config.vh

@@ -40,8 +40,13 @@
 `define EXT_F_ENABLE
 `endif
 
+// core-coupled tensor core
 `ifndef EXT_T_DISABLE
 `define EXT_T_ENABLE
+// decoupled Hopper-style tensor core
+`ifndef EXT_T_HOPPER
+`define EXT_T_HOPPER
+`endif
 `endif
 
 `ifndef XLEN_32
@@ -83,7 +88,7 @@
 `endif
 
 `ifndef NUM_CORES
-`define NUM_CORES 8
+`define NUM_CORES 4
 `endif
 
 `ifndef NUM_WARPS

hw/rtl/core/VX_decode.sv

@@ -542,16 +542,30 @@ module VX_decode  #(
                 endcase
             end
         `ifdef EXT_T_ENABLE
-            `INST_EXT4: begin
+            `ifdef EXT_T_HOPPER
-                ex_type = `EX_TENSOR;
+                // TODO
-                op_type = `INST_TENSOR_HMMA;
+                `INST_EXT4: begin
-                // tensor core macroop is encoded as r-type
+                    ex_type = `EX_TENSOR;
-                use_rd = 1;
+                    op_type = `INST_TENSOR_HMMA;
-                `USED_IREG (rd);
+                    // tensor core macroop is encoded as r-type
-                `USED_IREG (rs1);
+                    use_rd = 1;
-                `USED_IREG (rs2);
+                    `USED_IREG (rd);
-                `USED_IREG (rs3);
+                    `USED_IREG (rs1);
-            end
+                    `USED_IREG (rs2);
+                    `USED_IREG (rs3);
+                end
+            `else
+                `INST_EXT4: begin
+                    ex_type = `EX_TENSOR;
+                    op_type = `INST_TENSOR_HMMA;
+                    // tensor core macroop is encoded as r-type
+                    use_rd = 1;
+                    `USED_IREG (rd);
+                    `USED_IREG (rs1);
+                    `USED_IREG (rs2);
+                    `USED_IREG (rs3);
+                end
+            `endif
         `endif
             default:;
         endcase

hw/rtl/core/VX_tensor_core.sv

@@ -12,7 +12,7 @@ module VX_tensor_core import VX_gpu_pkg::*; #(
 );
     localparam BLOCK_SIZE = 1;
     localparam NUM_LANES  = `NUM_THREADS;
-    // FIXME: @perf: PARTIAL_BW==1 increases power instantiating
+    // @perf: PARTIAL_BW==1 increases power instantiating
     // stream_buffers for ISSUE_WIDTH times
     localparam PARTIAL_BW = (BLOCK_SIZE != `ISSUE_WIDTH) || (NUM_LANES != `NUM_THREADS);
 
@@ -51,16 +51,27 @@ module VX_tensor_core import VX_gpu_pkg::*; #(
     );
 
     for (genvar block_idx = 0; block_idx < BLOCK_SIZE; ++block_idx) begin
-        VX_tensor_core_block #(
+`ifdef EXT_T_HOPPER
+        VX_tensor_hopper_core_block #(
             .ISW(1), // FIXME: not block_idx
             .FP16(FP16)
+        ) tensor_hopper_core (
+            .clk(clk),
+            .reset(reset),
+            .execute_if(execute_if[block_idx]),
+            .commit_if(commit_block_if[block_idx])
+        );
+`else
+        VX_tensor_core_block #(
+            .ISW(1), // FIXME: use block_idx
+            .FP16(FP16)
         ) tensor_core (
             .clk(clk),
             .reset(reset),
-
             .execute_if(execute_if[block_idx]),
             .commit_if(commit_block_if[block_idx])
         );
+`endif
     end
     
 endmodule
@@ -275,7 +286,6 @@ module VX_tensor_core_block import VX_gpu_pkg::*; #(
     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[wb_wid], /* uuid ~ rd */
-        // execute_if_data_deq, /* uuid ~ rd */
         subcommit == 1'b0 ? wb_data_0 : wb_data_1, /* data */
         1'b0, /* pid */
         1'b1, /* sop */

hw/rtl/core/VX_tensor_hopper_core.sv

@@ -0,0 +1,102 @@
+`ifdef EXT_T_ENABLE
+`include "VX_fpu_define.vh"
+
+module VX_tensor_hopper_core_block import VX_gpu_pkg::*; #(
+    parameter ISW,
+    parameter FP16
+) (
+    input clk,
+    input reset,
+
+    VX_execute_if.slave execute_if,
+    VX_commit_if.master commit_if
+);
+    localparam METADATA_QUEUE_DEPTH = 2; // FIXME: arbitrary
+
+    /* commit_if.data_t parts that we need to keep around:
+        - uuid
+        - wid
+        - tmask
+        - PC
+        - wb
+        - rd
+    */
+
+    localparam DATAW = `UUID_WIDTH + `NW_WIDTH + `NUM_THREADS + `XLEN + 1 + `NR_BITS;
+
+    wire operand_enq_fire = execute_if.valid && execute_if.ready;
+    wire commit_if_fire = commit_if.valid && commit_if.ready;
+    wire [DATAW-1:0] execute_if_data_enq = {
+        execute_if.data.uuid,
+        execute_if.data.wid,
+        execute_if.data.tmask,
+        execute_if.data.PC,
+        execute_if.data.wb,
+        execute_if.data.rd
+        // pid/sop/eop set later
+    };
+
+    wire [`NUM_WARPS-1:0][DATAW-1:0] execute_if_data_deq;
+
+    wire [`NUM_WARPS-1:0] metadata_queue_fulls;
+    wire [`NUM_WARPS-1:0] metadata_queue_emptys;
+    // OR not AND, we don't want any warp full
+    wire metadata_queue_full = |(metadata_queue_fulls);
+    assign execute_if.ready = !metadata_queue_full;
+
+    `RUNTIME_ASSERT((!execute_if.valid || execute_if.data.wid == `NW_WIDTH'(0)),
+        ("runtime error: WGMMA execute not supported for warps other than 0!"))
+
+    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.
+        //
+        // This has to be separated per-warp, as otherwise requests from
+        // multiple warps can be enqueued interleaved, which makes it hard to
+        // ensure two consecutive dequeues are associated with the same warp for
+        // commit. (FIXME: this is not strictly necessary though.)
+
+        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));
+
+        VX_fifo_queue #(
+            .DATAW(DATAW),
+            .DEPTH(METADATA_QUEUE_DEPTH)
+        ) pending_uops (
+            .clk(clk),
+            .reset(reset),
+            .push(enq),
+            .pop(deq),
+            .data_in(execute_if_data_enq),
+            .data_out(execute_if_data_deq[i]),
+            .empty(metadata_queue_emptys[i]),
+            `UNUSED_PIN(alm_empty),
+            .full(metadata_queue_fulls[i]),
+            `UNUSED_PIN(alm_full),
+            `UNUSED_PIN(size)
+        );
+    end
+
+    // this shouldn't really happen unless there's a big contention over
+    // the commit stage
+    `RUNTIME_ASSERT(!(!reset && metadata_queue_full), ("tensor core uop queue is full!"))
+
+    // FIXME: only checks warp 0 for commit!
+    assign commit_if.valid = ~metadata_queue_emptys[0/*FIXME*/];
+
+    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 */
+        wb_data, /* data */
+        1'b0, /* pid */
+        1'b1, /* sop */
+        1'b1  /* eop */
+    };
+
+    assign commit_if.data = commit_if_data;
+endmodule
+
+`endif