riscv verilog

以下是一个简单的RISC-V处理器的Verilog代码示例。它实现了RV32I指令集的子集，包括基本的算术和逻辑操作，分支和跳转指令以及加载和存储指令。请注意，这只是一个示例，您可能需要根据您的需求进行修改和调整。

module riscv_cpu(
  input clk,
  input rst,
  input [31:0] mem_addr,
  input [31:0] mem_data_in,
  output [31:0] mem_data_out
);

reg [31:0] pc;
reg [31:0] ir;

reg [31:0] reg_file [31:0];
reg [4:0] opcode;
reg [6:0] funct3;
reg [6:0] funct7;
reg [4:0] rs1;
reg [4:0] rs2;
reg [4:0] rd;
reg [11:0] imm;

wire [31:0] alu_out;
wire [31:0] branch_target;

assign mem_data_out = reg_file[rd];

// Instruction fetch
always @(posedge clk) begin
  if (rst) begin
    pc <= 32'h00000000;
  end else begin
    pc <= pc + 4;
  end
end

// Instruction decode and execute
always @(posedge clk) begin
  if (rst) begin
    ir <= 32'h00000000;
    opcode <= 5'b00000;
    funct3 <= 3'b000;
    funct7 <= 7'b0000000;
    rs1 <= 5'b00000;
    rs2 <= 5'b00000;
    rd <= 5'b00000;
    imm <= 12'h000;
  end else begin
    ir <= mem_data_out;
    opcode <= ir[6:2];
    funct3 <= ir[14:12];
    funct7 <= ir[31:25];
    rs1 <= ir[19:15];
    rs2 <= ir[24:20];
    rd <= ir[11:7];
    imm <= {12{ir[31]}, ir[31:20]};
  end
end

// ALU operations
always @(*) begin
  case (funct3)
    3'b000: alu_out = reg_file[rs1] + reg_file[rs2]; // ADD
    3'b001: alu_out = reg_file[rs1] << reg_file[rs2]; // SLL
    3'b010: alu_out = reg_file[rs1] < reg_file[rs2]; // SLT
    3'b011: alu_out = reg_file[rs1] < reg_file[rs2]; // SLTU
    3'b100: alu_out = reg_file[rs1] ^ reg_file[rs2]; // XOR
    3'b101: alu_out = reg_file[rs1] >> reg_file[rs2]; // SRL
    3'b110: alu_out = reg_file[rs1] | reg_file[rs2]; // OR
    3'b111: alu_out = reg_file[rs1] & reg_file[rs2]; // AND
    default: alu_out = 0;
  endcase
end

// Branch and jump operations
always @(*) begin
  case (opcode)
    5'b11000: branch_target = pc + imm; // JALR
    5'b11011: branch_target = pc + imm; // JAL
    5'b11001: branch_target = (reg_file[rs1] == reg_file[rs2]) ? pc + imm : pc + 4; // BEQ
    5'b11010: branch_target = (reg_file[rs1] != reg_file[rs2]) ? pc + imm : pc + 4; // BNE
    default: branch_target = 0;
  endcase
end

// Register file operations
always @(posedge clk) begin
  if (rst) begin
    reg_file[0] <= 32'h00000000;
  end else begin
    case (opcode)
      5'b00011: reg_file[rd] <= mem_data_out; // LW
      5'b01011: mem_data_in <= reg_file[rs2]; // SW
      5'b00100: reg_file[rd] <= alu_out; // ADDI
      5'b11000: reg_file[rd] <= pc + 4; // JALR
      5'b11011: reg_file[rd] <= pc + 4; // JAL
      default: reg_file[rd] <= reg_file[rd]; // No operation
    endcase
  end
end

// Memory operations
always @(posedge clk) begin
  if (rst) begin
    mem_data_out <= 32'h00000000;
  end else begin
    case (opcode)
      5'b00011: mem_addr <= reg_file[rs1] + imm; // LW
      5'b01011: mem_addr <= reg_file[rs1] + imm; // SW
      default: mem_data_in <= mem_data_in; // No operation
    endcase
  end
end

// Program counter update
always @(posedge clk) begin
  if (rst) begin
    pc <= 32'h00000000;
  end else begin
    case (opcode)
      5'b11000: pc <= branch_target; // JALR
      5'b11011: pc <= branch_target; // JAL
      5'b11001: pc <= branch_target; // BEQ
      5'b11010: pc <= branch_target; // BNE
      default: pc <= pc; // No branch or jump
    endcase
  end
end

endmodule

该代码模块化，定义了一个名为riscv_cpu的模块，具有以下输入输出端口：

- clk：时钟输入
- rst：重置输入
- mem_addr：内存地址输入
- mem_data_in：内存数据输入
- mem_data_out：内存数据输出

Verilog代码使用always块来定义RISC-V处理器的行为。它包括指令获取、指令解码和执行、ALU操作、分支和跳转操作、寄存器文件操作和内存操作。此外，它还包括程序计数器的更新和寄存器文件中的读写操作。

这是一个简单的RISC-V处理器Verilog代码示例。根据需要进行修改和调整。