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`include "gfx/gfx_defs.sv"
module gfx_setup_bounds
(
input logic clk,
input raster_xy vertex_a,
vertex_b,
vertex_c,
input logic stall,
output raster_xy reference,
output coarse_dim span_x,
span_y
);
logic x_a_lt_b, x_a_lt_c, x_b_lt_c, y_a_lt_b, y_a_lt_c, y_b_lt_c;
raster_xy min, max, hold_a, hold_b, hold_c;
coarse_dim ref_x, ref_y;
raster_xy_prec min_prec, max_prec, ref_prec;
assign min_prec = min;
assign max_prec = max;
assign reference = ref_prec;
assign ref_prec.x.sub = 0;
assign ref_prec.x.fine = 0;
assign ref_prec.x.padding = {`GFX_RASTER_PAD_BITS{ref_x[$bits(ref_x) - 1]}};
assign {ref_prec.x.sign, ref_prec.x.coarse} = ref_x;
assign ref_prec.y.sub = 0;
assign ref_prec.y.fine = 0;
assign ref_prec.y.padding = {`GFX_RASTER_PAD_BITS{ref_y[$bits(ref_y) - 1]}};
assign {ref_prec.y.sign, ref_prec.y.coarse} = ref_y;
always_ff @(posedge clk)
if (!stall) begin
hold_a <= vertex_a;
hold_b <= vertex_b;
hold_c <= vertex_c;
x_a_lt_b <= vertex_a.x < vertex_b.x;
x_a_lt_c <= vertex_a.x < vertex_c.x;
x_b_lt_c <= vertex_b.x < vertex_c.x;
y_a_lt_b <= vertex_a.y < vertex_b.y;
y_a_lt_c <= vertex_a.y < vertex_c.y;
y_b_lt_c <= vertex_b.y < vertex_c.y;
if (x_a_lt_b) begin
min.x <= x_a_lt_c ? hold_a.x : hold_c.x;
max.x <= x_b_lt_c ? hold_c.x : hold_b.x;
end else begin
min.x <= x_b_lt_c ? hold_b.x : hold_c.x;
max.x <= x_a_lt_c ? hold_c.x : hold_a.x;
end
if (y_a_lt_b) begin
min.y <= y_a_lt_c ? hold_a.y : hold_c.y;
max.y <= y_b_lt_c ? hold_c.y : hold_b.y;
end else begin
min.y <= y_b_lt_c ? hold_b.y : hold_c.y;
max.y <= y_a_lt_c ? hold_c.y : hold_a.y;
end
ref_x <= {min_prec.x.sign, min_prec.x.coarse};
ref_y <= {min_prec.y.sign, min_prec.y.coarse};
span_x <= {max_prec.x.sign, max_prec.x.coarse} - {min_prec.x.sign, min_prec.x.coarse};
span_y <= {max_prec.y.sign, max_prec.y.coarse} - {min_prec.y.sign, min_prec.y.coarse};
end
endmodule
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