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`include "gfx/gfx_defs.sv"
module gfx_cmd
(
input logic clk,
rst_n,
input cmd_addr cmd_address,
input logic cmd_read,
cmd_write,
input cmd_word cmd_writedata,
output cmd_word cmd_readdata,
input logic vsync,
output logic swap_buffers,
enable_clear,
start_clear,
output rgb24 clear_color,
output logic program_start,
output cmd_word program_header_base,
program_header_size
);
rgb24 next_clear_color;
logic do_start_clear, next_start_clear, next_enable_clear, next_swap_buffers;
struct packed
{
logic[4:0] mbz;
logic start_frame,
enable_clear,
swap_buffers;
rgb24 clear_color;
} readdata_scan, writedata_scan;
assign cmd_readdata = readdata_scan;
assign writedata_scan = cmd_writedata;
assign readdata_scan.mbz = 0;
assign readdata_scan.clear_color = clear_color;
assign readdata_scan.enable_clear = enable_clear;
assign readdata_scan.swap_buffers = swap_buffers;
assign do_start_clear = writedata_scan.start_frame && writedata_scan.enable_clear;
always_ff @(posedge clk or negedge rst_n)
if (!rst_n) begin
start_clear <= 0;
enable_clear <= 0;
swap_buffers <= 0;
next_start_clear <= 0;
next_enable_clear <= 0;
next_swap_buffers <= 0;
program_start <= 0;
end else begin
start_clear <= 0;
program_start <= 0;
if (vsync) begin
start_clear <= next_start_clear;
enable_clear <= next_enable_clear;
swap_buffers <= next_swap_buffers;
end
if (cmd_write)
unique case (cmd_address[1:0])
`GFX_CMD_REG_ID: ;
`GFX_CMD_REG_SCAN: begin
next_enable_clear <= writedata_scan.enable_clear;
next_swap_buffers <= writedata_scan.swap_buffers;
if (!next_start_clear)
next_start_clear <= do_start_clear;
end
`GFX_CMD_REG_HEADER_BASE: ;
`GFX_CMD_REG_HEADER_SIZE:
program_start <= 1;
endcase
end
always_ff @(posedge clk) begin
if (vsync)
clear_color <= next_clear_color;
if (cmd_write)
unique case (cmd_address[1:0])
`GFX_CMD_REG_ID: ;
`GFX_CMD_REG_SCAN:
next_clear_color <= writedata_scan.clear_color;
`GFX_CMD_REG_HEADER_BASE:
program_header_base <= cmd_writedata;
`GFX_CMD_REG_HEADER_SIZE:
program_header_size <= cmd_writedata;
endcase
end
endmodule
|
