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54 lines
2.5 KiB
Systemverilog
54 lines
2.5 KiB
Systemverilog
///////////////////////////////////////////
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// adrdec.sv
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//
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// Written: David_Harris@hmc.edu 29 January 2021
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// Modified:
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//
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// Purpose: Address decoder
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//
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// Documentation: RISC-V System on Chip Design
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//
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// A component of the CORE-V-WALLY configurable RISC-V project.
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// https://github.com/openhwgroup/cvw
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//
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// Copyright (C) 2021-23 Harvey Mudd College & Oklahoma State University
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//
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// SPDX-License-Identifier: Apache-2.0 WITH SHL-2.1
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//
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// Licensed under the Solderpad Hardware License v 2.1 (the “License”); you may not use this file
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// except in compliance with the License, or, at your option, the Apache License version 2.0. You
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// may obtain a copy of the License at
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//
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// https://solderpad.org/licenses/SHL-2.1/
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//
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// Unless required by applicable law or agreed to in writing, any work distributed under the
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// License is distributed on an “AS IS” BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND,
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// either express or implied. See the License for the specific language governing permissions
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// and limitations under the License.
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////////////////////////////////////////////////////////////////////////////////////////////////
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module adrdec #(parameter PA_BITS) (
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input logic [PA_BITS-1:0] PhysicalAddress, // Physical address to decode
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input logic [PA_BITS-1:0] Base, Range, // Base and range of peripheral addresses
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input logic Supported, // Is this peripheral supported?
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input logic AccessValid, // Is the access type valid?
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input logic [1:0] Size, // Size of access
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input logic [3:0] SizeMask, // List of supported sizes: 0 = 8, 1 = 16, 2 = 32, 3 = 64-bit
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output logic Sel // Decoder selects this peripheral
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);
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logic Match; // Address matches in range
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logic SizeValid; // Size of access is valid
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// determine if an address is in a range starting at the base
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// for example, if Base = 0x04002000 and range = 0x00000FFF,
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// then anything address between 0x04002000 and 0x04002FFF should match (HSEL=1)
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assign Match = &((PhysicalAddress ~^ Base) | Range);
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// determine if legal size of access is being made (byte, halfword, word, doubleword)
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assign SizeValid = SizeMask[Size];
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// Select this peripheral if the address matches, the peripheral is supported, and the type and size of access is ok
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assign Sel = Match & Supported & AccessValid & SizeValid; // exclusion-tag: adrdecSel
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endmodule
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