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alirezamon |
// =============================================================================
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// COPYRIGHT NOTICE
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// Copyright 2006 (c) Lattice Semiconductor Corporation
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// ALL RIGHTS RESERVED
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// This confidential and proprietary software may be used only as authorised by
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// a licensing agreement from Lattice Semiconductor Corporation.
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// The entire notice above must be reproduced on all authorized copies and
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// copies may only be made to the extent permitted by a licensing agreement from
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// Lattice Semiconductor Corporation.
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//
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// Lattice Semiconductor Corporation TEL : 1-800-Lattice (USA and Canada)
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// 5555 NE Moore Court 408-826-6000 (other locations)
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// Hillsboro, OR 97124 web : http://www.latticesemi.com/
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// U.S.A email: techsupport@latticesemi.com
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// =============================================================================/
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// FILE DETAILS
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// Project : LatticeMico32
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// File : lm32_decoder.v
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// Title : Instruction decoder
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// Dependencies : lm32_include.v
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// Version : 6.1.17
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// =============================================================================
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`include "lm32_include.v"
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// Index of opcode field in an instruction
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`define LM32_OPCODE_RNG 31:26
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`define LM32_OP_RNG 30:26
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// Opcodes - Some are only listed as 5 bits as their MSB is a don't care
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`define LM32_OPCODE_ADD 5'b01101
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`define LM32_OPCODE_AND 5'b01000
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`define LM32_OPCODE_ANDHI 6'b011000
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`define LM32_OPCODE_B 6'b110000
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`define LM32_OPCODE_BI 6'b111000
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`define LM32_OPCODE_BE 6'b010001
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`define LM32_OPCODE_BG 6'b010010
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`define LM32_OPCODE_BGE 6'b010011
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`define LM32_OPCODE_BGEU 6'b010100
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`define LM32_OPCODE_BGU 6'b010101
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`define LM32_OPCODE_BNE 6'b010111
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`define LM32_OPCODE_CALL 6'b110110
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`define LM32_OPCODE_CALLI 6'b111110
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`define LM32_OPCODE_CMPE 5'b11001
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`define LM32_OPCODE_CMPG 5'b11010
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`define LM32_OPCODE_CMPGE 5'b11011
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`define LM32_OPCODE_CMPGEU 5'b11100
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`define LM32_OPCODE_CMPGU 5'b11101
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`define LM32_OPCODE_CMPNE 5'b11111
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`define LM32_OPCODE_DIVU 6'b100011
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`define LM32_OPCODE_LB 6'b000100
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`define LM32_OPCODE_LBU 6'b010000
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`define LM32_OPCODE_LH 6'b000111
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`define LM32_OPCODE_LHU 6'b001011
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`define LM32_OPCODE_LW 6'b001010
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`define LM32_OPCODE_MODU 6'b110001
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`define LM32_OPCODE_MUL 5'b00010
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`define LM32_OPCODE_NOR 5'b00001
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`define LM32_OPCODE_OR 5'b01110
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`define LM32_OPCODE_ORHI 6'b011110
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`define LM32_OPCODE_RAISE 6'b101011
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`define LM32_OPCODE_RCSR 6'b100100
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`define LM32_OPCODE_SB 6'b001100
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`define LM32_OPCODE_SEXTB 6'b101100
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`define LM32_OPCODE_SEXTH 6'b110111
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`define LM32_OPCODE_SH 6'b000011
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`define LM32_OPCODE_SL 5'b01111
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`define LM32_OPCODE_SR 5'b00101
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`define LM32_OPCODE_SRU 5'b00000
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`define LM32_OPCODE_SUB 6'b110010
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`define LM32_OPCODE_SW 6'b010110
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`define LM32_OPCODE_USER 6'b110011
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`define LM32_OPCODE_WCSR 6'b110100
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`define LM32_OPCODE_XNOR 5'b01001
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`define LM32_OPCODE_XOR 5'b00110
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/////////////////////////////////////////////////////
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// Module interface
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/////////////////////////////////////////////////////
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module lm32_decoder (
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// ----- Inputs -------
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instruction,
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// ----- Outputs -------
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d_result_sel_0,
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d_result_sel_1,
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x_result_sel_csr,
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`ifdef LM32_MC_ARITHMETIC_ENABLED
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x_result_sel_mc_arith,
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`endif
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`ifdef LM32_NO_BARREL_SHIFT
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x_result_sel_shift,
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`endif
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`ifdef CFG_SIGN_EXTEND_ENABLED
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x_result_sel_sext,
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`endif
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x_result_sel_logic,
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`ifdef CFG_USER_ENABLED
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x_result_sel_user,
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`endif
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x_result_sel_add,
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m_result_sel_compare,
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`ifdef CFG_PL_BARREL_SHIFT_ENABLED
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m_result_sel_shift,
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`endif
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w_result_sel_load,
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`ifdef CFG_PL_MULTIPLY_ENABLED
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w_result_sel_mul,
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`endif
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x_bypass_enable,
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m_bypass_enable,
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read_enable_0,
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read_idx_0,
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read_enable_1,
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read_idx_1,
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write_enable,
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write_idx,
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immediate,
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branch_offset,
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load,
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store,
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size,
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sign_extend,
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adder_op,
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logic_op,
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`ifdef CFG_PL_BARREL_SHIFT_ENABLED
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direction,
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`endif
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`ifdef CFG_MC_BARREL_SHIFT_ENABLED
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shift_left,
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shift_right,
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`endif
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`ifdef CFG_MC_MULTIPLY_ENABLED
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multiply,
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`endif
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`ifdef CFG_MC_DIVIDE_ENABLED
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divide,
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modulus,
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`endif
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branch,
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branch_reg,
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condition,
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`ifdef CFG_DEBUG_ENABLED
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break,
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`endif
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scall,
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eret,
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`ifdef CFG_DEBUG_ENABLED
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bret,
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`endif
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`ifdef CFG_USER_ENABLED
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user_opcode,
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`endif
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csr_write_enable
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);
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/////////////////////////////////////////////////////
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// Inputs
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/////////////////////////////////////////////////////
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input [`LM32_INSTRUCTION_RNG] instruction; // Instruction to decode
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/////////////////////////////////////////////////////
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// Outputs
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/////////////////////////////////////////////////////
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output [`LM32_D_RESULT_SEL_0_RNG] d_result_sel_0;
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reg [`LM32_D_RESULT_SEL_0_RNG] d_result_sel_0;
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output [`LM32_D_RESULT_SEL_1_RNG] d_result_sel_1;
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reg [`LM32_D_RESULT_SEL_1_RNG] d_result_sel_1;
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output x_result_sel_csr;
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reg x_result_sel_csr;
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`ifdef LM32_MC_ARITHMETIC_ENABLED
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output x_result_sel_mc_arith;
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reg x_result_sel_mc_arith;
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`endif
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`ifdef LM32_NO_BARREL_SHIFT
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output x_result_sel_shift;
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reg x_result_sel_shift;
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`endif
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`ifdef CFG_SIGN_EXTEND_ENABLED
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output x_result_sel_sext;
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reg x_result_sel_sext;
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`endif
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output x_result_sel_logic;
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reg x_result_sel_logic;
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`ifdef CFG_USER_ENABLED
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output x_result_sel_user;
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reg x_result_sel_user;
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`endif
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output x_result_sel_add;
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reg x_result_sel_add;
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output m_result_sel_compare;
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reg m_result_sel_compare;
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`ifdef CFG_PL_BARREL_SHIFT_ENABLED
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output m_result_sel_shift;
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reg m_result_sel_shift;
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`endif
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output w_result_sel_load;
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reg w_result_sel_load;
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`ifdef CFG_PL_MULTIPLY_ENABLED
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output w_result_sel_mul;
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reg w_result_sel_mul;
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`endif
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output x_bypass_enable;
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wire x_bypass_enable;
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output m_bypass_enable;
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wire m_bypass_enable;
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output read_enable_0;
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wire read_enable_0;
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output [`LM32_REG_IDX_RNG] read_idx_0;
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wire [`LM32_REG_IDX_RNG] read_idx_0;
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output read_enable_1;
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wire read_enable_1;
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output [`LM32_REG_IDX_RNG] read_idx_1;
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wire [`LM32_REG_IDX_RNG] read_idx_1;
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output write_enable;
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wire write_enable;
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output [`LM32_REG_IDX_RNG] write_idx;
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wire [`LM32_REG_IDX_RNG] write_idx;
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output [`LM32_WORD_RNG] immediate;
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wire [`LM32_WORD_RNG] immediate;
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output [`LM32_PC_RNG] branch_offset;
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wire [`LM32_PC_RNG] branch_offset;
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output load;
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wire load;
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output store;
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wire store;
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output [`LM32_SIZE_RNG] size;
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wire [`LM32_SIZE_RNG] size;
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output sign_extend;
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wire sign_extend;
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output adder_op;
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wire adder_op;
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output [`LM32_LOGIC_OP_RNG] logic_op;
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wire [`LM32_LOGIC_OP_RNG] logic_op;
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`ifdef CFG_PL_BARREL_SHIFT_ENABLED
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output direction;
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wire direction;
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`endif
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`ifdef CFG_MC_BARREL_SHIFT_ENABLED
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output shift_left;
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wire shift_left;
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output shift_right;
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wire shift_right;
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`endif
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`ifdef CFG_MC_MULTIPLY_ENABLED
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output multiply;
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wire multiply;
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`endif
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`ifdef CFG_MC_DIVIDE_ENABLED
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output divide;
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wire divide;
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output modulus;
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wire modulus;
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`endif
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output branch;
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wire branch;
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output branch_reg;
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wire branch_reg;
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output [`LM32_CONDITION_RNG] condition;
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wire [`LM32_CONDITION_RNG] condition;
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`ifdef CFG_DEBUG_ENABLED
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output break;
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wire break;
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`endif
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output scall;
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wire scall;
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output eret;
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wire eret;
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`ifdef CFG_DEBUG_ENABLED
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output bret;
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wire bret;
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`endif
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`ifdef CFG_USER_ENABLED
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output [`LM32_USER_OPCODE_RNG] user_opcode;
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wire [`LM32_USER_OPCODE_RNG] user_opcode;
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`endif
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output csr_write_enable;
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wire csr_write_enable;
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/////////////////////////////////////////////////////
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// Internal nets and registers
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/////////////////////////////////////////////////////
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wire [`LM32_WORD_RNG] extended_immediate; // Zero or sign extended immediate
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wire [`LM32_WORD_RNG] high_immediate; // Immediate as high 16 bits
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wire [`LM32_WORD_RNG] call_immediate; // Call immediate
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wire [`LM32_WORD_RNG] branch_immediate; // Conditional branch immediate
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wire sign_extend_immediate; // Whether the immediate should be sign extended (`TRUE) or zero extended (`FALSE)
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wire select_high_immediate; // Whether to select the high immediate
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wire select_call_immediate; // Whether to select the call immediate
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/////////////////////////////////////////////////////
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// Functions
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/////////////////////////////////////////////////////
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`define INCLUDE_FUNCTION
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`include "lm32_functions.v"
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/////////////////////////////////////////////////////
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// Combinational logic
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/////////////////////////////////////////////////////
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// Determine opcode
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wire op_add = instruction[`LM32_OP_RNG] == `LM32_OPCODE_ADD;
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wire op_and = instruction[`LM32_OP_RNG] == `LM32_OPCODE_AND;
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wire op_andhi = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_ANDHI;
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wire op_b = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_B;
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wire op_bi = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BI;
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wire op_be = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BE;
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wire op_bg = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BG;
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wire op_bge = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BGE;
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wire op_bgeu = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BGEU;
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wire op_bgu = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BGU;
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wire op_bne = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_BNE;
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wire op_call = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_CALL;
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wire op_calli = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_CALLI;
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wire op_cmpe = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPE;
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wire op_cmpg = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPG;
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wire op_cmpge = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPGE;
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wire op_cmpgeu = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPGEU;
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wire op_cmpgu = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPGU;
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wire op_cmpne = instruction[`LM32_OP_RNG] == `LM32_OPCODE_CMPNE;
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`ifdef CFG_MC_DIVIDE_ENABLED
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wire op_divu = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_DIVU;
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`endif
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wire op_lb = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LB;
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wire op_lbu = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LBU;
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wire op_lh = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LH;
|
330 |
|
|
wire op_lhu = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LHU;
|
331 |
|
|
wire op_lw = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_LW;
|
332 |
|
|
`ifdef CFG_MC_DIVIDE_ENABLED
|
333 |
|
|
wire op_modu = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_MODU;
|
334 |
|
|
`endif
|
335 |
|
|
`ifdef LM32_MULTIPLY_ENABLED
|
336 |
|
|
wire op_mul = instruction[`LM32_OP_RNG] == `LM32_OPCODE_MUL;
|
337 |
|
|
`endif
|
338 |
|
|
wire op_nor = instruction[`LM32_OP_RNG] == `LM32_OPCODE_NOR;
|
339 |
|
|
wire op_or = instruction[`LM32_OP_RNG] == `LM32_OPCODE_OR;
|
340 |
|
|
wire op_orhi = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_ORHI;
|
341 |
|
|
wire op_raise = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_RAISE;
|
342 |
|
|
wire op_rcsr = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_RCSR;
|
343 |
|
|
wire op_sb = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SB;
|
344 |
|
|
`ifdef CFG_SIGN_EXTEND_ENABLED
|
345 |
|
|
wire op_sextb = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SEXTB;
|
346 |
|
|
wire op_sexth = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SEXTH;
|
347 |
|
|
`endif
|
348 |
|
|
wire op_sh = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SH;
|
349 |
|
|
`ifdef LM32_BARREL_SHIFT_ENABLED
|
350 |
|
|
wire op_sl = instruction[`LM32_OP_RNG] == `LM32_OPCODE_SL;
|
351 |
|
|
`endif
|
352 |
|
|
wire op_sr = instruction[`LM32_OP_RNG] == `LM32_OPCODE_SR;
|
353 |
|
|
wire op_sru = instruction[`LM32_OP_RNG] == `LM32_OPCODE_SRU;
|
354 |
|
|
wire op_sub = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SUB;
|
355 |
|
|
wire op_sw = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_SW;
|
356 |
|
|
wire op_user = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_USER;
|
357 |
|
|
wire op_wcsr = instruction[`LM32_OPCODE_RNG] == `LM32_OPCODE_WCSR;
|
358 |
|
|
wire op_xnor = instruction[`LM32_OP_RNG] == `LM32_OPCODE_XNOR;
|
359 |
|
|
wire op_xor = instruction[`LM32_OP_RNG] == `LM32_OPCODE_XOR;
|
360 |
|
|
|
361 |
|
|
// Group opcodes by function
|
362 |
|
|
wire arith = op_add | op_sub;
|
363 |
|
|
wire logicc = op_and | op_andhi | op_nor | op_or | op_orhi | op_xor | op_xnor;
|
364 |
|
|
wire cmp = op_cmpe | op_cmpg | op_cmpge | op_cmpgeu | op_cmpgu | op_cmpne;
|
365 |
|
|
wire bra = op_b | op_bi | op_be | op_bg | op_bge | op_bgeu | op_bgu | op_bne;
|
366 |
|
|
wire call = op_call | op_calli;
|
367 |
|
|
`ifdef LM32_BARREL_SHIFT_ENABLED
|
368 |
|
|
wire shift = op_sl | op_sr | op_sru;
|
369 |
|
|
`endif
|
370 |
|
|
`ifdef LM32_NO_BARREL_SHIFT
|
371 |
|
|
wire shift = op_sr | op_sru;
|
372 |
|
|
`endif
|
373 |
|
|
`ifdef CFG_MC_BARREL_SHIFT_ENABLED
|
374 |
|
|
assign shift_left = op_sl;
|
375 |
|
|
assign shift_right = op_sr | op_sru;
|
376 |
|
|
`endif
|
377 |
|
|
`ifdef CFG_SIGN_EXTEND_ENABLED
|
378 |
|
|
wire sext = op_sextb | op_sexth;
|
379 |
|
|
`endif
|
380 |
|
|
`ifdef LM32_MULTIPLY_ENABLED
|
381 |
|
|
wire multiply = op_mul;
|
382 |
|
|
`endif
|
383 |
|
|
`ifdef CFG_MC_DIVIDE_ENABLED
|
384 |
|
|
assign divide = op_divu;
|
385 |
|
|
assign modulus = op_modu;
|
386 |
|
|
`endif
|
387 |
|
|
assign load = op_lb | op_lbu | op_lh | op_lhu | op_lw;
|
388 |
|
|
assign store = op_sb | op_sh | op_sw;
|
389 |
|
|
|
390 |
|
|
// Select pipeline multiplexor controls
|
391 |
|
|
always @*
|
392 |
|
|
begin
|
393 |
|
|
// D stage
|
394 |
|
|
if (call)
|
395 |
|
|
d_result_sel_0 = `LM32_D_RESULT_SEL_0_NEXT_PC;
|
396 |
|
|
else
|
397 |
|
|
d_result_sel_0 = `LM32_D_RESULT_SEL_0_REG_0;
|
398 |
|
|
if (call)
|
399 |
|
|
d_result_sel_1 = `LM32_D_RESULT_SEL_1_ZERO;
|
400 |
|
|
else if ((instruction[31] == 1'b0) && !bra)
|
401 |
|
|
d_result_sel_1 = `LM32_D_RESULT_SEL_1_IMMEDIATE;
|
402 |
|
|
else
|
403 |
|
|
d_result_sel_1 = `LM32_D_RESULT_SEL_1_REG_1;
|
404 |
|
|
// X stage
|
405 |
|
|
x_result_sel_csr = `FALSE;
|
406 |
|
|
`ifdef LM32_MC_ARITHMETIC_ENABLED
|
407 |
|
|
x_result_sel_mc_arith = `FALSE;
|
408 |
|
|
`endif
|
409 |
|
|
`ifdef LM32_NO_BARREL_SHIFT
|
410 |
|
|
x_result_sel_shift = `FALSE;
|
411 |
|
|
`endif
|
412 |
|
|
`ifdef CFG_SIGN_EXTEND_ENABLED
|
413 |
|
|
x_result_sel_sext = `FALSE;
|
414 |
|
|
`endif
|
415 |
|
|
x_result_sel_logic = `FALSE;
|
416 |
|
|
`ifdef CFG_USER_ENABLED
|
417 |
|
|
x_result_sel_user = `FALSE;
|
418 |
|
|
`endif
|
419 |
|
|
x_result_sel_add = `FALSE;
|
420 |
|
|
if (op_rcsr)
|
421 |
|
|
x_result_sel_csr = `TRUE;
|
422 |
|
|
`ifdef LM32_MC_ARITHMETIC_ENABLED
|
423 |
|
|
`ifdef CFG_MC_BARREL_SHIFT_ENABLED
|
424 |
|
|
else if (shift_left | shift_right)
|
425 |
|
|
x_result_sel_mc_arith = `TRUE;
|
426 |
|
|
`endif
|
427 |
|
|
`ifdef CFG_MC_DIVIDE_ENABLED
|
428 |
|
|
else if (divide | modulus)
|
429 |
|
|
x_result_sel_mc_arith = `TRUE;
|
430 |
|
|
`endif
|
431 |
|
|
`ifdef CFG_MC_MULTIPLY_ENABLED
|
432 |
|
|
else if (multiply)
|
433 |
|
|
x_result_sel_mc_arith = `TRUE;
|
434 |
|
|
`endif
|
435 |
|
|
`endif
|
436 |
|
|
`ifdef LM32_NO_BARREL_SHIFT
|
437 |
|
|
else if (shift)
|
438 |
|
|
x_result_sel_shift = `TRUE;
|
439 |
|
|
`endif
|
440 |
|
|
`ifdef CFG_SIGN_EXTEND_ENABLED
|
441 |
|
|
else if (sext)
|
442 |
|
|
x_result_sel_sext = `TRUE;
|
443 |
|
|
`endif
|
444 |
|
|
else if (logicc)
|
445 |
|
|
x_result_sel_logic = `TRUE;
|
446 |
|
|
`ifdef CFG_USER_ENABLED
|
447 |
|
|
else if (op_user)
|
448 |
|
|
x_result_sel_user = `TRUE;
|
449 |
|
|
`endif
|
450 |
|
|
else
|
451 |
|
|
x_result_sel_add = `TRUE;
|
452 |
|
|
|
453 |
|
|
// M stage
|
454 |
|
|
|
455 |
|
|
m_result_sel_compare = cmp;
|
456 |
|
|
`ifdef CFG_PL_BARREL_SHIFT_ENABLED
|
457 |
|
|
m_result_sel_shift = shift;
|
458 |
|
|
`endif
|
459 |
|
|
|
460 |
|
|
// W stage
|
461 |
|
|
w_result_sel_load = load;
|
462 |
|
|
`ifdef CFG_PL_MULTIPLY_ENABLED
|
463 |
|
|
w_result_sel_mul = op_mul;
|
464 |
|
|
`endif
|
465 |
|
|
end
|
466 |
|
|
|
467 |
|
|
// Set if result is valid at end of X stage
|
468 |
|
|
assign x_bypass_enable = arith
|
469 |
|
|
| logicc
|
470 |
|
|
`ifdef CFG_MC_BARREL_SHIFT_ENABLED
|
471 |
|
|
| shift_left
|
472 |
|
|
| shift_right
|
473 |
|
|
`endif
|
474 |
|
|
`ifdef CFG_MC_MULTIPLY_ENABLED
|
475 |
|
|
| multiply
|
476 |
|
|
`endif
|
477 |
|
|
`ifdef CFG_MC_DIVIDE_ENABLED
|
478 |
|
|
| divide
|
479 |
|
|
| modulus
|
480 |
|
|
`endif
|
481 |
|
|
`ifdef LM32_NO_BARREL_SHIFT
|
482 |
|
|
| shift
|
483 |
|
|
`endif
|
484 |
|
|
`ifdef CFG_SIGN_EXTEND_ENABLED
|
485 |
|
|
| sext
|
486 |
|
|
`endif
|
487 |
|
|
`ifdef CFG_USER_ENABLED
|
488 |
|
|
| op_user
|
489 |
|
|
`endif
|
490 |
|
|
| op_rcsr
|
491 |
|
|
;
|
492 |
|
|
// Set if result is valid at end of M stage
|
493 |
|
|
assign m_bypass_enable = x_bypass_enable
|
494 |
|
|
`ifdef CFG_PL_BARREL_SHIFT_ENABLED
|
495 |
|
|
| shift
|
496 |
|
|
`endif
|
497 |
|
|
| cmp
|
498 |
|
|
;
|
499 |
|
|
// Register file read port 0
|
500 |
|
|
assign read_enable_0 = ~(op_bi | op_calli);
|
501 |
|
|
assign read_idx_0 = instruction[25:21];
|
502 |
|
|
// Register file read port 1
|
503 |
|
|
assign read_enable_1 = ~(op_bi | op_calli | load);
|
504 |
|
|
assign read_idx_1 = instruction[20:16];
|
505 |
|
|
// Register file write port
|
506 |
|
|
assign write_enable = ~(bra | op_raise | store | op_wcsr);
|
507 |
|
|
assign write_idx = call
|
508 |
|
|
? 5'd29
|
509 |
|
|
: instruction[31] == 1'b0
|
510 |
|
|
? instruction[20:16]
|
511 |
|
|
: instruction[15:11];
|
512 |
|
|
|
513 |
|
|
// Size of load/stores
|
514 |
|
|
assign size = instruction[27:26];
|
515 |
|
|
// Whether to sign or zero extend
|
516 |
|
|
assign sign_extend = instruction[28];
|
517 |
|
|
// Set adder_op to 1 to perform a subtraction
|
518 |
|
|
assign adder_op = op_sub | op_cmpe | op_cmpg | op_cmpge | op_cmpgeu | op_cmpgu | op_cmpne | bra;
|
519 |
|
|
// Logic operation (and, or, etc)
|
520 |
|
|
assign logic_op = instruction[29:26];
|
521 |
|
|
`ifdef CFG_PL_BARREL_SHIFT_ENABLED
|
522 |
|
|
// Shift direction
|
523 |
|
|
assign direction = instruction[29];
|
524 |
|
|
`endif
|
525 |
|
|
// Control flow microcodes
|
526 |
|
|
assign branch = bra | call;
|
527 |
|
|
assign branch_reg = op_call | op_b;
|
528 |
|
|
assign condition = instruction[28:26];
|
529 |
|
|
`ifdef CFG_DEBUG_ENABLED
|
530 |
|
|
assign break = op_raise & ~instruction[2];
|
531 |
|
|
`endif
|
532 |
|
|
assign scall = op_raise & instruction[2];
|
533 |
|
|
assign eret = op_b & (instruction[25:21] == 5'd30);
|
534 |
|
|
`ifdef CFG_DEBUG_ENABLED
|
535 |
|
|
assign bret = op_b & (instruction[25:21] == 5'd31);
|
536 |
|
|
`endif
|
537 |
|
|
`ifdef CFG_USER_ENABLED
|
538 |
|
|
// Extract user opcode
|
539 |
|
|
assign user_opcode = instruction[10:0];
|
540 |
|
|
`endif
|
541 |
|
|
// CSR read/write
|
542 |
|
|
assign csr_write_enable = op_wcsr;
|
543 |
|
|
|
544 |
|
|
// Extract immediate from instruction
|
545 |
|
|
|
546 |
|
|
assign sign_extend_immediate = ~(op_and | op_cmpgeu | op_cmpgu | op_nor | op_or | op_xnor | op_xor);
|
547 |
|
|
assign select_high_immediate = op_andhi | op_orhi;
|
548 |
|
|
assign select_call_immediate = instruction[31];
|
549 |
|
|
|
550 |
|
|
assign high_immediate = {instruction[15:0], 16'h0000};
|
551 |
|
|
assign extended_immediate = {{16{sign_extend_immediate & instruction[15]}}, instruction[15:0]};
|
552 |
|
|
assign call_immediate = {{6{instruction[25]}}, instruction[25:0]};
|
553 |
|
|
assign branch_immediate = {{16{instruction[15]}}, instruction[15:0]};
|
554 |
|
|
|
555 |
|
|
assign immediate = select_high_immediate == `TRUE
|
556 |
|
|
? high_immediate
|
557 |
|
|
: extended_immediate;
|
558 |
|
|
|
559 |
|
|
assign branch_offset = select_call_immediate == `TRUE
|
560 |
|
|
? call_immediate
|
561 |
|
|
: branch_immediate;
|
562 |
|
|
|
563 |
|
|
endmodule
|
564 |
|
|
|