platform/wavelet3d: implement shader cores

This commit contains over a month of intermittent work (I don't have
enough free time to do this the right way)

1 files changed, 31 insertions, 0 deletions

diff --git a/platform/wavelet3d/gfx_skid_flow.sv b/platform/wavelet3d/gfx_skid_flow.sv
new file mode 100644
index 0000000..7890ae3
--- /dev/null
+++ b/platform/wavelet3d/gfx_skid_flow.sv
@@ -0,0 +1,31 @@
+module gfx_skid_flow
+(
+	input  logic clk,
+	             rst_n,
+
+	input  logic in_valid,
+	             out_ready,
+
+	output logic in_ready,
+	             out_valid,
+	             stall
+);
+
+	logic was_ready, was_valid;
+
+	assign stall = ~in_ready;
+	assign in_ready = was_ready | ~was_valid;
+	assign out_valid = in_valid | stall;
+
+	always_ff @(posedge clk or negedge rst_n)
+		if (~rst_n) begin
+			was_ready <= 0;
+			was_valid <= 0;
+		end else begin
+			was_ready <= out_ready;
+
+			if (~stall)
+				was_valid <= in_valid;
+		end
+
+endmodule