| // Copyright 2017 ETH Zurich and University of Bologna. |
| // Copyright and related rights are licensed under the Solderpad Hardware |
| // License, Version 0.51 (the “License”); you may not use this file except in |
| // compliance with the License. You may obtain a copy of the License at |
| // http://solderpad.org/licenses/SHL-0.51. Unless required by applicable law |
| // or agreed to in writing, software, hardware and materials distributed under |
| // this License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR |
| // CONDITIONS OF ANY KIND, either express or implied. See the License for the |
| // specific language governing permissions and limitations under the License. |
| |
| module dc_data_buffer(clk, rstn, write_pointer, write_data, read_pointer, read_data); |
| |
| parameter DATA_WIDTH = 32; |
| parameter BUFFER_DEPTH = 8; |
| |
| // `ifndef PULP_FPGA_EMUL |
| // function integer log2(input integer value); |
| // begin |
| // value = value - 1; |
| // for (log2 = 0; value > 0; log2 = log2 + 1) |
| // value = value >> 1; |
| // end |
| // endfunction |
| // `define log2(N) log2(N) |
| // `else |
| `define log2(N) ((N)<=(1) ? 0 : (N)<=(2) ? 1 : (N)<=(4) ? 2 : (N)<=(8) ? 3 : (N)<=(16) ? 4 : (N)<=(32) ? 5 : (N)<=(64) ? 6 : (N)<=(128) ? 7 : (N)<=(256) ? 8 : (N)<=(512) ? 9 : (N)<=(1024) ? 10 : -1) |
| // `endif |
| |
| input clk; |
| input rstn; |
| |
| input [BUFFER_DEPTH - 1 : 0] write_pointer; |
| input [DATA_WIDTH - 1 : 0] write_data; |
| input [BUFFER_DEPTH - 1 : 0] read_pointer; |
| output [DATA_WIDTH - 1 : 0] read_data; |
| |
| reg [DATA_WIDTH - 1 : 0] data[BUFFER_DEPTH - 1 : 0]; |
| |
| integer loop; |
| |
| always @(posedge clk or negedge rstn) |
| begin: read_write_data |
| if (rstn == 1'b0) |
| for (loop = 0; loop < BUFFER_DEPTH; loop = loop + 1) |
| data[loop] <= 'h0; |
| else |
| data[`log2(write_pointer)] <= write_data; |
| end |
| |
| assign read_data = data[`log2(read_pointer)]; |
| |
| endmodule |