260 lines
9.0 KiB
Verilog
260 lines
9.0 KiB
Verilog
`include "VX_define.vh"
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module VX_warp_sched #(
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parameter CORE_ID = 0
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) (
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input wire clk,
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input wire reset,
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VX_warp_ctl_if warp_ctl_if,
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VX_wstall_if wstall_if,
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VX_join_if join_if,
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VX_branch_ctl_if branch_ctl_if,
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VX_ifetch_rsp_if ifetch_rsp_if,
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VX_ifetch_req_if ifetch_req_if,
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output wire busy
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);
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wire join_fall;
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wire [31:0] join_pc;
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wire [`NUM_THREADS-1:0] join_tm;
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reg [`NUM_WARPS-1:0] warp_active;
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reg [`NUM_WARPS-1:0] warp_stalled;
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reg [`NUM_WARPS-1:0] visible_active;
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wire update_visible_active;
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reg [`NUM_WARPS-1:0] warp_lock;
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reg [`NUM_THREADS-1:0] thread_masks[`NUM_WARPS-1:0];
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reg [31:0] warp_pcs[`NUM_WARPS-1:0];
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// barriers
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reg [`NUM_WARPS-1:0] barrier_stall_mask[`NUM_BARRIERS-1:0];
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wire reached_barrier_limit;
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reg [`NUM_WARPS-1:0] total_barrier_stall;
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// wspawn
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reg [31:0] use_wspawn_pc;
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reg [`NUM_WARPS-1:0] use_wspawn;
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wire [`NUM_THREADS-1:0] thread_mask;
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wire [31:0] warp_pc;
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wire [`NW_BITS-1:0] warp_to_schedule;
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wire scheduled_warp;
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wire stall_out;
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wire global_stall;
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wire real_schedule;
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reg didnt_split;
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always @(posedge clk) begin
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if (reset) begin
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for (integer i = 0; i < `NUM_BARRIERS; i++) begin
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barrier_stall_mask[i] <= 0;
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end
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use_wspawn_pc <= 0;
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use_wspawn <= 0;
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warp_pcs[0] <= `STARTUP_ADDR;
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warp_active[0] <= 1; // Activating first warp
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visible_active[0] <= 1; // Activating first warp
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thread_masks[0] <= 1; // Activating first thread in first warp
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warp_stalled <= 0;
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didnt_split <= 0;
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warp_lock <= 0;
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for (integer i = 1; i < `NUM_WARPS; i++) begin
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warp_pcs[i] <= 0;
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warp_active[i] <= 0; // Activating first warp
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visible_active[i] <= 0; // Activating first warp
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thread_masks[i] <= 1; // Activating first thread in first warp
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end
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end else begin
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if (warp_ctl_if.wspawn.valid) begin
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warp_active <= warp_ctl_if.wspawn.wmask;
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use_wspawn <= warp_ctl_if.wspawn.wmask & (~`NUM_WARPS'(1));
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use_wspawn_pc <= warp_ctl_if.wspawn.pc;
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end
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if (warp_ctl_if.barrier.valid) begin
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warp_stalled[warp_ctl_if.wid] <= 0;
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if (reached_barrier_limit) begin
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barrier_stall_mask[warp_ctl_if.barrier.id] <= 0;
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end else begin
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barrier_stall_mask[warp_ctl_if.barrier.id][warp_ctl_if.wid] <= 1;
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end
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end else if (warp_ctl_if.tmc.valid) begin
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thread_masks[warp_ctl_if.wid] <= warp_ctl_if.tmc.thread_mask;
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warp_stalled[warp_ctl_if.wid] <= 0;
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if (0 == warp_ctl_if.tmc.thread_mask) begin
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warp_active[warp_ctl_if.wid] <= 0;
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visible_active[warp_ctl_if.wid] <= 0;
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end
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end else if (join_if.is_join && !didnt_split) begin
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if (!join_fall) begin
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warp_pcs[join_if.wid] <= join_pc;
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end
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thread_masks[join_if.wid] <= join_tm;
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didnt_split <= 0;
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end else if (warp_ctl_if.split.valid) begin
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warp_stalled[warp_ctl_if.wid] <= 0;
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if (warp_ctl_if.split.diverged) begin
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thread_masks[warp_ctl_if.wid] <= warp_ctl_if.split.then_mask;
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didnt_split <= 0;
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end else begin
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didnt_split <= 1;
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end
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end
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if (use_wspawn[warp_to_schedule] && !global_stall) begin
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use_wspawn[warp_to_schedule] <= 0;
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thread_masks[warp_to_schedule] <= 1;
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end
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// Stalling the scheduling of warps
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if (wstall_if.wstall) begin
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warp_stalled[wstall_if.wid] <= 1;
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visible_active[wstall_if.wid] <= 0;
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end
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// Refilling active warps
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if (update_visible_active) begin
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visible_active <= warp_active & ~warp_stalled & ~total_barrier_stall & ~warp_lock;
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end
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// Don't change state if stall
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if (!global_stall && real_schedule && (thread_mask != 0)) begin
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visible_active[warp_to_schedule] <= 0;
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warp_pcs[warp_to_schedule] <= warp_pc + 4;
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end
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// Branch
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if (branch_ctl_if.valid) begin
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if (branch_ctl_if.taken) begin
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warp_pcs[branch_ctl_if.wid] <= branch_ctl_if.dest;
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end
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warp_stalled[branch_ctl_if.wid] <= 0;
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end
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// Lock/Release
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if (scheduled_warp && !stall_out) begin
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warp_lock[warp_to_schedule] <= 1;
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end
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if (ifetch_rsp_if.valid && ifetch_rsp_if.ready) begin
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warp_lock[ifetch_rsp_if.wid] <= 0;
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end
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end
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end
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wire [`NUM_WARPS-1:0] b_mask = barrier_stall_mask[warp_ctl_if.barrier.id][`NUM_WARPS-1:0];
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wire [`NW_BITS:0] b_count;
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VX_countones #(
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.N(`NUM_WARPS)
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) barrier_count (
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.valids(b_mask),
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.count (b_count)
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);
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wire [`NW_BITS:0] count_visible_active;
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VX_countones #(
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.N(`NUM_WARPS)
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) num_visible (
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.valids(visible_active),
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.count (count_visible_active)
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);
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assign reached_barrier_limit = (b_count == warp_ctl_if.barrier.num_warps);
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assign total_barrier_stall = barrier_stall_mask[0] | barrier_stall_mask[1] | barrier_stall_mask[2] | barrier_stall_mask[3];
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wire [(1+32+`NUM_THREADS-1):0] ipdom[`NUM_WARPS-1:0];
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wire [(1+32+`NUM_THREADS-1):0] q1 = {1'b1, 32'b0, thread_masks[warp_ctl_if.wid]};
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wire [(1+32+`NUM_THREADS-1):0] q2 = {1'b0, warp_ctl_if.split.pc, warp_ctl_if.split.else_mask};
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assign {join_fall, join_pc, join_tm} = ipdom[join_if.wid];
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for (genvar i = 0; i < `NUM_WARPS; i++) begin
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wire push = warp_ctl_if.split.valid
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&& warp_ctl_if.split.diverged
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&& (i == warp_ctl_if.wid);
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wire pop = join_if.is_join
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&& (i == join_if.wid);
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VX_ipdom_stack #(
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.WIDTH(1+32+`NUM_THREADS),
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.DEPTH(`NT_BITS+1)
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) ipdom_stack (
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.clk (clk),
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.reset(reset),
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.push (push),
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.pop (pop),
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.q1 (q1),
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.q2 (q2),
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.d (ipdom[i]),
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`UNUSED_PIN (empty),
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`UNUSED_PIN (full)
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);
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end
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wire schedule;
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wire branch_hazard = schedule
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&& branch_ctl_if.valid
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&& branch_ctl_if.taken
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&& (branch_ctl_if.wid == warp_to_schedule);
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assign real_schedule = schedule
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&& !warp_stalled[warp_to_schedule]
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&& !total_barrier_stall[warp_to_schedule]
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&& !warp_lock[0];
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wire wstall_this_cycle = wstall_if.wstall && (wstall_if.wid == warp_to_schedule); // Maybe bug
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assign update_visible_active = (0 == count_visible_active) && !(stall_out || wstall_this_cycle || branch_hazard || join_if.is_join);
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assign global_stall = stall_out || wstall_this_cycle || branch_hazard || !real_schedule || join_if.is_join;
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assign scheduled_warp = !(wstall_this_cycle || branch_hazard || !real_schedule || join_if.is_join) && !reset;
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assign warp_pc = use_wspawn[warp_to_schedule] ? use_wspawn_pc : warp_pcs[warp_to_schedule];
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assign thread_mask = global_stall ? 0 : (use_wspawn[warp_to_schedule] ? `NUM_THREADS'(1) : thread_masks[warp_to_schedule]);
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wire [`NUM_WARPS-1:0] use_active = (count_visible_active != 0) ? visible_active :
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(warp_active & ~warp_stalled & ~total_barrier_stall & ~warp_lock);
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// Choosing a warp to schedule
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VX_fixed_arbiter #(
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.N(`NUM_WARPS)
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) choose_schedule (
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.clk (clk),
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.reset (reset),
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.requests (use_active),
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.grant_index (warp_to_schedule),
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.grant_valid (schedule),
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`UNUSED_PIN (grant_onehot)
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);
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assign stall_out = ~ifetch_req_if.ready && ifetch_req_if.valid;
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VX_generic_register #(
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.N(1 + `NUM_THREADS + 32 + `NW_BITS)
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) fetch_reg (
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.clk (clk),
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.reset (reset),
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.stall (stall_out),
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.flush (0),
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.in ({(| thread_mask), thread_mask, warp_pc, warp_to_schedule}),
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.out ({ifetch_req_if.valid, ifetch_req_if.thread_mask, ifetch_req_if.curr_PC, ifetch_req_if.wid})
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);
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assign busy = (warp_active != 0);
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endmodule |