From 3e8235aa71a930be815e03230b64bb850b6ffdb4 Mon Sep 17 00:00:00 2001
From: Alejandro Soto <alejandro@34project.org>
Date: Sun, 12 Nov 2023 23:42:59 -0600
Subject: rtl/gfx: move funnel out of frag

---
 rtl/gfx/gfx_funnel.sv | 85 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 85 insertions(+)
 create mode 100644 rtl/gfx/gfx_funnel.sv

(limited to 'rtl/gfx/gfx_funnel.sv')

diff --git a/rtl/gfx/gfx_funnel.sv b/rtl/gfx/gfx_funnel.sv
new file mode 100644
index 0000000..22fefe3
--- /dev/null
+++ b/rtl/gfx/gfx_funnel.sv
@@ -0,0 +1,85 @@
+`include "gfx/gfx_defs.sv"
+
+module gfx_funnel
+(
+	input  logic         clk,
+	                     rst_n,
+
+	input  frag_xy_lanes fragments,
+	input  bary_lanes    barys,
+	input  paint_lanes   in_valid,
+	output logic         in_ready,
+
+	input  logic         out_ready,
+	output logic         out_valid,
+	output frag_xy       frag,
+	output fixed_tri     bary
+);
+
+	logic skid_ready, stall, ready, valid;
+	frag_xy next_frag, out_frag;
+	fixed_tri next_bary, out_bary;
+	bary_lanes barys_hold;
+	paint_lanes current, next;
+	frag_xy_lanes fragments_hold;
+
+	assign ready = !(|next);
+	assign in_ready = skid_ready && ready;
+
+	gfx_skid_buf #(.WIDTH($bits(frag))) skid_frag
+	(
+		.in(out_frag),
+		.out(frag),
+		.*
+	);
+
+	gfx_skid_buf #(.WIDTH($bits(bary))) skid_bary
+	(
+		.in(out_bary),
+		.out(bary),
+		.*
+	);
+
+	gfx_skid_flow skid_flow
+	(
+		.in_ready(skid_ready),
+		.in_valid(valid),
+		.*
+	);
+
+	always_comb begin
+		next = 0;
+		next_bary = {($bits(next_bary)){1'bx}};
+		next_frag = {($bits(next_frag)){1'bx}};
+
+		for (integer i = 0; i < `GFX_FINE_LANES; ++i)
+			if (current[i]) begin
+				next = current;
+				next[i] = 0;
+
+				next_bary = barys_hold[i];
+				next_frag = fragments_hold[i];
+			end
+	end
+
+	always_ff @(posedge clk or negedge rst_n)
+		if (!rst_n) begin
+			valid <= 0;
+			current <= 0;
+		end else if (!stall) begin
+			valid <= |current;
+			current <= ready ? in_valid : next;
+		end
+
+	always_ff @(posedge clk)
+		if (!stall) begin
+			if (ready) begin
+				barys_hold <= barys;
+				fragments_hold <= fragments;
+			end
+
+			out_bary <= next_bary;
+			out_frag <= next_frag;
+		end
+
+endmodule
-- 
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