# Lab 10-11
Name: G Jaswanth
Roll No.: CS22B020

---

## TopModule

module Top;
    
    genvar i;
    input [31:0] instruction_memory[0:255];
    input [31:0] data_memory[0:255];
    input [31:0] reg_file[0:31];
    wire [31:0] PC = 32'h0;
    input clk;
   
    always @(posedge clk) begin
        if (reset) begin
            PC <= 32'h0;
        end else begin
            PC <= PC + 1;
        end
    end

    always @(*) begin
        wire [6:0] opcode;      
        wire [4:0] rd;
        wire [4:0] rs1;
        wire [4:0] rs2;
        wire [6:0] fun7;
        wire [11:0] immediate;

        InstructionDecoder uut(instruction_memory[PC], opcode, rd, rs1, rs2, fun7, immediate);
        RegisterRead uut1(reg_file, rs1, rs1_value);
        RegisterRead uut2(reg_file, rs2, rs2_value);

        wire [31:0] alu_output;
        wire [31:0] loaded_val;

        if (opcode == 7'b0001011) begin
            ALU alu(rs1_value, immediate, opcode, alu_output);
            MemoryRead mr(alu_output, 1'b1, data_memory, loaded_val);
            RegisterWrite regwr(reg_file, rd, loaded_val, 1'b1);
        end else if (opcode == 7'b0001100) begin
            ALU alu(rs1_value, immediate, opcode, alu_output);
            MemoryWrite memwr(rs2_value, alu_output, 1'b1, data_memory);
        end else begin
            RegisterWrite regwr(reg_file, rd, alu_output, 1'b1);
        end
    end
endmodule

---
## ALU

    module ALU(input [31:0]a,input [31:0]b,input [6:0]opcode,output reg [31:0]out);
//assuming inputs-7 bit size
    wire [31:0]w1,w2,w3,w4,w5,w6,w8,w9,w10,w11,w12,w7;
    add_32bit a1(.a(a),.b(b),.y(w1));
    sub_32bit a2(.a(a),.b(b),.y(w2));
    xor_32bit a3(.a(a),.b(b),.y(w3));
    or_32bit a4(.a(a),.b(b),.y(w4));
    and_32bit a5(.a(a),.b(b),.y(w5));
    sll_32bit a6(.a(a),.b(b),.y(w6));
    srl_32bit a7(.a(a),.b(b),.y(w7));
    sra_32bit a8(.a(a),.b(b),.y(w8));
    slt_32bit a9(.a(a),.b(b),.y(w9));
    sltu_32bit a10(.a(a),.b(b),.y(w10));
    lw a11(.rs(a),.offset(b),.y(w11));
    lw a12(.rs(a),.offset(b),.y(w12));
    always @(*) begin
    integer i;
     // Default output to all zeros
    for (i = 0; i < 32; i = i + 1) begin
           mux_16to1 ma(w1[i],w2[i],w3[i],w4[i],w6[i],w7[i],w1[i],w8[i],w9[i],w10[i],w11[i],w12[i],opcode[3],opcode[2],opcode[1],opcode[0],out[i]);
    end
end
   endmodule

---
## Helper Modules

 module not_32bit
(
input [31:0] a, ,
output [31:0] y
);
    not a0(y[0], a[0]);
    not a1(y[1], a[1]);
    not a2(y[2], a[2]);
    not a3(y[3], a[3]);
    not a0(y[4], a[4]);
    not a1(y[5], a[5]);
    not a2(y[6], a[6]);
    not a3(y[7], a[7]);
    not a0(y[8], a[8]);
    not a1(y[9], a[9]);
    not a2(y[10], a[10]);
    not a3(y[11], a[11]);
    not a0(y[12], a[12]);
    not a1(y[13], a[13]);
    not a2(y[14], a[14]);
    not a3(y[15], a[15]);
    not a0(y[16], a[16]);
    not a1(y[17], a[17]);
    not a2(y[18], a[18]);
    not a3(y[19], a[19]);
    not a0(y[20], a[20]);
    not a1(y[21], a[21]);
    not a2(y[22], a[22]);
    not a3(y[23], a[23]);
    not a0(y[24], a[24]);
    not a1(y[25], a[25]);
    not a2(y[26], a[26]);
    not a3(y[27], a[27]);
    not a0(y[28], a[28]);
    not a1(y[29], a[29]);
    not a2(y[30], a[30]);
    not a3(y[31], a[31]);
endmodule


module or_32bit
(
input [31:0] a, b,
output [31:0] y
);
or a0(y[0], a[0], b[0]);
or a1(y[1], a[1], b[1]);
or a2(y[2], a[2], b[2]);
or a3(y[3], a[3], b[3]);
or a0(y[4], a[4], b[4]);
or a1(y[5], a[5], b[5]);
or a2(y[6], a[6], b[6]);
or a3(y[7], a[7], b[7]);
or a0(y[8], a[8], b[8]);
or a1(y[9], a[9], b[9]);
or a2(y[10], a[10], b[10]);
or a3(y[11], a[11], b[11]);
or a0(y[12], a[12], b[12]);
or a1(y[13], a[13], b[13]);
or a2(y[14], a[14], b[14]);
or a3(y[15], a[15], b[15]);
or a0(y[16], a[16], b[16]);
or a1(y[17], a[17], b[17]);
or a2(y[18], a[18], b[18]);
or a3(y[19], a[19], b[19]);
or a0(y[20], a[20], b[20]);
or a1(y[21], a[21], b[21]);
or a2(y[22], a[22], b[22]);
or a3(y[23], a[23], b[23]);
or a0(y[24], a[24], b[24]);
or a1(y[25], a[25], b[25]);
or a2(y[26], a[26], b[26]);
or a3(y[27], a[27], b[27]);
or a0(y[28], a[28], b[28]);
or a1(y[29], a[29], b[29]);
or a2(y[30], a[30], b[30]);
or a3(y[31], a[31], b[31]);
endmodule


module and_32bit
(
input [31:0] a, b,
output [31:0] y
);

and a0(y[0], a[0], b[0]);
and a1(y[1], a[1], b[1]);
and a2(y[2], a[2], b[2]);
and a3(y[3], a[3], b[3]);
and a0(y[4], a[4], b[4]);
and a1(y[5], a[5], b[5]);
and a2(y[6], a[6], b[6]);
and a3(y[7], a[7], b[7]);
and a0(y[8], a[8], b[8]);
and a1(y[9], a[9], b[9]);
and a2(y[10], a[10], b[10]);
and a3(y[11], a[11], b[11]);
and a0(y[12], a[12], b[12]);
and a1(y[13], a[13], b[13]);
and a2(y[14], a[14], b[14]);
and a3(y[15], a[15], b[15]);
and a0(y[16], a[16], b[16]);
and a1(y[17], a[17], b[17]);
and a2(y[18], a[18], b[18]);
and a3(y[19], a[19], b[19]);
and a0(y[20], a[20], b[20]);
and a1(y[21], a[21], b[21]);
and a2(y[22], a[22], b[22]);
and a3(y[23], a[23], b[23]);
and a0(y[24], a[24], b[24]);
and a1(y[25], a[25], b[25]);
and a2(y[26], a[26], b[26]);
and a3(y[27], a[27], b[27]);
and a0(y[28], a[28], b[28]);
and a1(y[29], a[29], b[29]);
and a2(y[30], a[30], b[30]);
and a3(y[31], a[31], b[31]);
endmodule


module xor_32bit
(
input [31:0] a, b,
output [31:0] y
);
    xor a0(y[0], a[0], b[0]);
    xor a1(y[1], a[1], b[1]);
    xor a2(y[2], a[2], b[2]);
    xor a3(y[3], a[3], b[3]);
    xor a0(y[4], a[4], b[4]);
    xor a1(y[5], a[5], b[5]);
    xor a2(y[6], a[6], b[6]);
    xor a3(y[7], a[7], b[7]);
    xor a0(y[8], a[8], b[8]);
    xor a1(y[9], a[9], b[9]);
    xor a2(y[10], a[10], b[10]);
    xor a3(y[11], a[11], b[11]);
    xor a0(y[12], a[12], b[12]);
    xor a1(y[13], a[13], b[13]);
    xor a2(y[14], a[14], b[14]);
    xor a3(y[15], a[15], b[15]);
    xor a0(y[16], a[16], b[16]);
    xor a1(y[17], a[17], b[17]);
    xor a2(y[18], a[18], b[18]);
    xor a3(y[19], a[19], b[19]);
    xor a0(y[20], a[20], b[20]);
    xor a1(y[21], a[21], b[21]);
    xor a2(y[22], a[22], b[22]);
    xor a3(y[23], a[23], b[23]);
    xor a0(y[24], a[24], b[24]);
    xor a1(y[25], a[25], b[25]);
    xor a2(y[26], a[26], b[26]);
    xor a3(y[27], a[27], b[27]);
    xor a0(y[28], a[28], b[28]);
    xor a1(y[29], a[29], b[29]);
    xor a2(y[30], a[30], b[30]);
    xor a3(y[31], a[31], b[31]);
endmodule


module lw (
    input [31:0] rs,     
    input [31:0] offset,  
    output [31:0] y       
);
wire cout;
  add_32bit uut(rs,offset,0,y,cout);
endmodule



//ripplecarryadder
module add_32bit(input [31:0]a,b, input cin, output [31:0]sum,output c32);

wire c1,c2,c3,c4,c5,c6,c7,c8,c9,c10,c11,c12,c13,c14,c15,c16,c17,c189,c19,c20,c21,c22,c23,c24,c25,c26,c27,c28,c29,c30,c31;

full_adder fa0(a[0],b[0],cin,sum[0],c1);
full_adder fa1(a[1],b[1],c1,sum[1],c2);
full_adder fa2(a[2],b[2],c2,sum[2],c3);
full_adder fa3(a[3],b[3],c3,sum[3],c4);
full_adder fa4(a[4],b[4],c4,sum[4],c5);
full_adder fa5(a[5],b[5],c5,sum[5],c6);
full_adder fa6(a[6],b[6],c6,sum[6],c7);
full_adder fa7(a[7],b[7],c7,sum[7],c8);
full_adder fa8(a[8],b[8],c8,sum[8],c9);
full_adder fa9(a[9],b[9],c9,sum[9],c10);
full_adder fa10(a[10],b[10],c10,sum[10],c11);
full_adder fa11(a[11],b[11],c11,sum[11],c12);
full_adder fa12(a[12],b[12],c12,sum[12],c13);
full_adder fa13(a[13],b[13],c13,sum[13],c14);
full_adder fa14(a[14],b[14],c14,sum[14],c15);
full_adder fa15(a[15],b[15],c15,sum[15],c16);
full_adder fa16(a[16],b[16],c16,sum[16],c17);
full_adder fa17(a[17],b[17],c17,sum[17],c18);
full_adder fa18(a[18],b[18],c18,sum[18],c19);
full_adder fa19(a[19],b[19],c19,sum[19],c20);
full_adder fa20(a[20],b[20],c20,sum[20],c21);
full_adder fa21(a[21],b[21],c21,sum[21],c22);
full_adder fa22(a[22],b[22],c22,sum[22],c23);
full_adder fa23(a[23],b[23],c23,sum[23],c24);
full_adder fa24(a[24],b[24],c24,sum[24],c25);
full_adder fa25(a[25],b[25],c25,sum[25],c26);
full_adder fa26(a[26],b[26],c26,sum[26],c27);
full_adder fa27(a[27],b[27],c27,sum[27],c28);
full_adder fa28(a[28],b[28],c28,sum[28],c29);
full_adder fa29(a[29],b[29],c29,sum[29],c30);
full_adder fa30(a[30],b[30],c30,sum[30],c31);
full_adder fa31(a[31],b[31],c31,sum[31],c32);
endmodule



module sll_32bit (
    input [31:0] a,  // Input A
    input [31:0] b,   // Input B (shift amount)
    output [31:0] y  // Output Y (result of shift)
);
    assign y = a << b;  // Perform left logical shift
endmodule



module srl_32bit (
    input [31:0] a,  // Input A
    input [31:0] b,   // Input B (shift amount)
    output [31:0] y  // Output Y (result of shift)
);
    assign y = a >> b;  // Perform right logical shift
endmodule


module sra_32bit (
    input [31:0] a,  // Input A
    input [31:0] b,   // Input B (shift amount)
    output [31:0] y  // Output Y (result of shift)
);
    assign y = a >>> b;  // Perform right arithmetic shift
endmodule


module slt_32bit (
    input [31:0] a,  // Input A
    input [31:0] b,  // Input B
    output y         // Output Y (result of comparison)
);
    assign y = (a < b) ? 1'b1 : 1'b0;  // Perform signed less than comparison
endmodule


module slt_32bit (
    input [31:0] a,  // Input A
    input [31:0] b,  // Input B
    output y         // Output Y (result of comparison)
);
    assign y = (a < b) ? 1'b1 : 1'b0;  // Perform signed less than comparison
endmodule


module sub_32bit(
    input [31:0] a,
    input [31:0] b,
    output [31:0] sum,
    output c32
);
wire [31:0]w1;
not_32bit Notification(b,w1);
// Instantiate the ripple carry adder module
ripplecarryadder ripple_carry_adder_inst (
    .a(a),
    .b(w1),
    .cin(1'b1),
    .sum(sum),
    .c32(c32)
);

endmodule


//fulladder

module FullAdder(a,b,cin,sum,cout);
input a,b,cin;
output sum,cout;
wire s0,c1;
wire c2;
HalfAdder ha0(.a(a),.b(b),.sum(s0),.cout(c1));
HalfAdder ha1(.a(cin),.b(s0),.sum(sum),.cout(c2));
assign cout = c1 | c2 ;
endmodule

//halfadder

module HalfAdder(a,b,sum,cout);
input a,b;
output sum,cout;
assign sum = a^ b;
assign cout = a & b;
endmodule

---
## MUX

module mux_16to1(input sum, diff, xor, or , and , sll , srl , sra , slt, sltu , lw ,sw ,
                 input s1, s2, s3, s4,
                 output reg data_out);

always @(*) begin
    data_out = (s1 & s2 & s3 & s4 & 0) |
               (s1 & s2 & s3 & ~s4 & 0) |
               (s1 & s2 & ~s3 & s4 & 0) |
               (s1 & s2 & ~s3 & ~s4 & 0) |
               (s1 & ~s2 & s3 & s4 & sw) |
               (s1 & ~s2 & s3 & ~s4 & lw) |
               (s1 & ~s2 & ~s3 & s4 & sltu) |
               (s1 & ~s2 & ~s3 & ~s4 & slt) |
               (~s1 & s2 & s3 & s4 & sra) |
               (~s1 & s2 & s3 & ~s4 & srl) |
               (~s1 & s2 & ~s3 & s4 & sll) |
               (~s1 & s2 & ~s3 & ~s4 & and) |
               (~s1 & ~s2 & s3 & s4 & or) |
               (~s1 & ~s2 & s3 & ~s4 & xor) |
               (~s1 & ~s2 & ~s3 & s4 & diff) |
               (~s1 & ~s2 & ~s3 & ~s4 & sum);
end

endmodule

---
## Modules in datapath & control

module InstructionDecoder (
    input wire [31:0] instruction,  // Input: 32-bit instruction
    output reg [6:0] opcode,        // Output: Opcode field (7 bits)
    output reg [4:0] rd,            // Output: Destination register field (5 bits)
    output reg [4:0] rs1,           // Output: Source register 1 field (5 bits)
    output reg [4:0] rs2,           // Output: Source register 2 field (5 bits)
    output reg [6:0] fun7,          // Output: Fun7 field (7 bits)
    output reg [11:0] immediate     // Output: Immediate value (12 bits)
);

// Define opcode values
parameter OPCODE_D11 = 7'b0001011;  // Opcode value for decimal 11
parameter OPCODE_12 = 7'000b1100;  // Opcode value for decimal 12

// Decode instruction fields
always @(*) begin
    opcode = instruction[6:0];     // Extract opcode field (bits 6-0)
    rd = instruction[11:7];        // Extract rd field (bits 11-7)
    rs1 = instruction[19:15];      // Extract rs1 field (bits 19-15)
    rs2 = instruction[24:20];      // Extract rs2 field (bits 24-20)
    fun7 = instruction[31:25];     // Extract fun7 field (bits 31-25)
    
    // Check if opcode is 'd11'
    if (opcode == OPCODE_D11) begin
        // Concatenate rs2 and fun7 bits to form immediate value
        immediate = {rs2, fun7};
    end else if (opcode == OPCODE_12) begin
        // Concatenate rd and fun7 bits to form immediate value
        immediate = {rd, fun7};
    end else begin
        // If opcode does not match, set immediate to 0
        immediate = 12'b0;
    end
end

endmodule

---

module MemoryWrite (
    input [31:0] data_in,           // Data to write to memory
    input [9:0] address,            // Address to write to in memory
    input write_enable,             // Write enable signal
    output reg [31:0] memory [0:255]  // Memory array
);
    // Write to memory if write_enable is asserted
    always @* begin
        if (write_enable) begin
            memory[address] <= data_in;
        end
    end
endmodule

---

module RegisterWrite (
    input [31:0] registers [0:31],  // Array of 32 registers
    input [4:0] write_address,       // Write address
    input [31:0] write_data,         // Data to write
    input write_enable               // Write enable signal
);
    // Write to register if write_enable is asserted
    always @(posedge clk) begin
        if (write_enable) begin
            registers[write_address] <= write_data;
        end
    end
endmodule

---

module ProgramCounter (
    input wire clk,      // Clock input
    input wire reset,    // Reset input
    output reg [31:0] pc_output  // Output: Program Counter (PC)
);

// Define the Program Counter (PC) register
reg [31:0] pc;

// Increment PC on every clock cycle
always @(posedge clk or posedge reset) begin
    if (reset)
        pc <= 0;  // Reset PC to initial value
    else
        pc <= pc + 1;  // Increment PC
end

// Output the PC value
assign pc_output = pc;

endmodule

---

module MemoryRead (
    input [9:0] address,            // Address to read from in memory
    input read_enable,              // Read enable signal
    input [31:0] memory [0:255],   // Memory array
    output reg [31:0] data_out      // Data read from memory
);
    // Read from memory if read_enable is asserted
    always @* begin
        if (read_enable) begin
            data_out = memory[address];
        end
    end
endmodule

---

 module RegisterRead (
    input [31:0] registers [0:31],  // Array of 32 registers
    input [4:0] read_address,        // Read address
    output reg [31:0] read_data      // Output data read from register
);
    // Read data from register
    always @* begin
        read_data = registers[read_address];
    end
endmodule

---