mips_16.v

`timescale 1ns / 1ps
//////////////////////////////////////////////////////////////////////////////////
// Company: 
// Engineer: Het soni
// 
// Create Date:    17:25:19 10/11/2022 
// Design Name: 
// Module Name:    mips_16 
// Project Name: 
// Target Devices: 
// Tool versions: 
// Description: 
//
// Dependencies: 
//
// Revision: 
// Revision 0.01 - File Created
// Additional Comments: 
//
//////////////////////////////////////////////////////////////////////////////////
module mips_16( input clk,reset,  
                output[15:0] pc_out, alu_result
                           //,reg3,reg4  
   );  
 reg[15:0] pc_current;  
 wire signed[15:0] pc_next,pc2;  
 wire [15:0] instr;  
 wire[1:0] reg_dst,mem_to_reg,alu_op;  
 wire jump,branch,mem_read,mem_write,alu_src,reg_write     ;  
 wire     [2:0]     reg_write_dest;  
 wire     [15:0] reg_write_data;  
 wire     [2:0]     reg_read_addr_1;  
 wire     [15:0] reg_read_data_1;  
 wire     [2:0]     reg_read_addr_2;  
 wire     [15:0] reg_read_data_2;  
 wire [15:0] sign_ext_im,read_data2,zero_ext_im,imm_ext;  
 wire JRControl;  
 wire [2:0] ALU_Control;  
 wire [15:0] ALU_out;  
 wire zero_flag;  
 wire signed[15:0] im_shift_1, PC_j, PC_beq, PC_4beq,PC_4beqj,PC_jr;  
 wire beq_control;  
 wire [14:0] jump_shift_1;  
 wire [15:0]mem_read_data;  
 wire [15:0] no_sign_ext;  
 wire sign_or_zero;  
 // PC   
 always @(posedge clk or posedge reset)  
 begin   
      if(reset)   
           pc_current <= 16'd0;  
      else  
           pc_current <= pc_next;  
 end  
 // PC + 2   
 assign pc2 = pc_current + 16'd2;  
 // instruction memory  
 instr_mem instrucion_memory(.pc(pc_current),.instruction(instr));  
 // jump shift left 1  
 assign jump_shift_1 = {instr[13:0],1'b0};  
 // control unit  
 control control_unit(.reset(reset),.opcode(instr[15:13]),.reg_dst(reg_dst)  
                ,.mem_to_reg(mem_to_reg),.alu_op(alu_op),.jump(jump),.branch(branch),.mem_read(mem_read),  
                .mem_write(mem_write),.alu_src(alu_src),.reg_write(reg_write),.sign_or_zero(sign_or_zero));  
 // multiplexer regdest  
 assign reg_write_dest = (reg_dst==2'b10) ? 3'b111: ((reg_dst==2'b01) ? instr[6:4] :instr[9:7]);  
 // register file  
 assign reg_read_addr_1 = instr[12:10];  
 assign reg_read_addr_2 = instr[9:7];  
 register_file reg_file(.clk(clk),.rst(reset),.reg_write_en(reg_write),  
 .reg_write_dest(reg_write_dest),  
 .reg_write_data(reg_write_data),  
 .reg_read_addr_1(reg_read_addr_1),  
 .reg_read_data_1(reg_read_data_1),  
 .reg_read_addr_2(reg_read_addr_2),  
 .reg_read_data_2(reg_read_data_2)); 
 //.reg3(reg3),  
 //.reg4(reg4));  
 // sign extend  
 assign sign_ext_im = {{9{instr[6]}},instr[6:0]};  
 assign zero_ext_im = {{9{1'b0}},instr[6:0]};  
 assign imm_ext = (sign_or_zero==1'b1) ? sign_ext_im : zero_ext_im;  
 // JR control  
 JR_Control JRControl_unit(.alu_op(alu_op),.funct(instr[3:0]),.JRControl(JRControl));       
 // ALU control unit  
 ALUControl ALU_Control_unit(.ALUOp(alu_op),.Function(instr[3:0]),.ALU_Control(ALU_Control));  
 // multiplexer alu_src  
 assign read_data2 = (alu_src==1'b1) ? imm_ext : reg_read_data_2;  
 // ALU   
 alu alu_unit(.a(reg_read_data_1),.b(read_data2),.alu_control(ALU_Control),.result(ALU_out),.zero(zero_flag));  
 // immediate shift 1  
 assign im_shift_1 = {imm_ext[14:0],1'b0};  
 //  
 assign no_sign_ext = ~(im_shift_1) + 1'b1;  
 // PC beq add  
 assign PC_beq = (im_shift_1[15] == 1'b1) ? (pc2 - no_sign_ext): (pc2 +im_shift_1);  
 // beq control  
 assign beq_control = branch & zero_flag;  
 // PC_beq  
 assign PC_4beq = (beq_control==1'b1) ? PC_beq : pc2;  
 // PC_j  
 assign PC_j = {pc2[15],jump_shift_1};  
 // PC_4beqj  
 assign PC_4beqj = (jump == 1'b1) ? PC_j : PC_4beq;  
 // PC_jr  
 assign PC_jr = reg_read_data_1;  
 // PC_next  
 assign pc_next = (JRControl==1'b1) ? PC_jr : PC_4beqj;  
 // data memory  
 data_memory datamem(.clk(clk),.mem_access_addr(ALU_out),  
 .mem_write_data(reg_read_data_2),.mem_write_en(mem_write),.mem_read(mem_read),  
 .mem_read_data(mem_read_data));  
 // write back  
 assign reg_write_data = (mem_to_reg == 2'b10) ? pc2:((mem_to_reg == 2'b01)? mem_read_data: ALU_out);  
 // output  
 assign pc_out = pc_current;  
 assign alu_result = ALU_out;  
 endmodule