103 lines
3.4 KiB
Plaintext
103 lines
3.4 KiB
Plaintext
// Sumbission for ELEC4720 Assignment 1 Question 5
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// Oliver Boutros (c3428958)
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// Riley King-Saunders (cc3430382)
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`ifndef SHIFTER_H_SV
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`define SHIFTER_H_SV
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module shifter #(width=2)(input logic [2:0] op,
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input logic[2**width-1:0] A, input logic[2**width-1:0] B, input logic[width-1:0] C,
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output logic[2**width-1:0] OUT_1);
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// A and B are 2^n bits wide and C is n bits wide as according to the docs
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always_comb begin
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case (op)
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3'b000: OUT_1 = A << C;
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3'b001: OUT_1 = A >> C;
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3'b011: OUT_1 = $signed(A) >>> C;
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3'b100: OUT_1 = A << B;
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3'b101: OUT_1 = A >> B;
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3'b111: OUT_1 = $signed(A) >>> B;
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default:OUT_1 = A;
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endcase
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end
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endmodule
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`endif
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// Testbench
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module shifter_tb #(width=4)();
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logic [2:0] op;
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logic [2**width-1:0] Y;
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logic [2**width-1:0] A_in;
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logic [2**width-1:0] B_in;
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logic [width-1:0] C_in;
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logic [2:0] ops[6];
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logic [2**width-1:0] A[6];
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logic [2**width-1:0] B[6];
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logic [width-1:0] C[6];
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logic [2**width-1:0] Y_exp[6];
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shifter #(width) dut(op, A_in,B_in,C_in,Y);
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integer error_count;
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initial begin
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// Test left shift by C
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ops[0] = 3'b000;
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A[0] = {{(2**width-1){1'b0}}, {1'b1}};
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C[0] = {{(width-1){1'b0}}, {1'b1}};
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B[0] = {2**width{1'b0}};
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Y_exp[0] = {{(2**width-2){1'b0}}, {2'b10}};
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// Test left shift by B
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ops[1] = 3'b100;
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A[1] = {{(2**width-1){1'b0}}, {1'b1}};
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C[1] = {{(width-1){1'b0}}, {1'b1}};
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B[1] = {{(2**width-2){1'b0}}, 2'b10};
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Y_exp[1] = {{(2**width-3){1'b0}}, {3'b100}};
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// Test Logical right shift by C
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ops[2] = 3'b001;
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A[2] = {{(2**width-2){1'b0}}, {2'b10}};
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C[2] = {{(width-1){1'b0}}, {1'b1}};
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B[2] = {2**width{1'b0}};
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Y_exp[2] = {{(2**width-1){1'b0}}, {1'b1}};
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// Test Logical right shift by B
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ops[3] = 3'b101;
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A[3] = {{(2**width-1){1'b0}}, {2'b10}};
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C[3] = {{(width-1){1'b0}}, {1'b1}};
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B[3] = {{(2**width-2){1'b0}}, 2'b10};
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Y_exp[3] = {{(2**width-1){1'b0}}, {1'b0}};
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// Test arithmetic shift right by C
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ops[4] = 3'b011;
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A[4] = {{(2**width-1){1'b1}}, 1'b0}; // -2
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C[4] = {{(width-1){1'b0}}, 1'b1}; // 1
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B[4] = {{(2**width-2){1'b0}}, 2'b10}; // 2
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Y_exp[4] = {2**width{1'b1}}; // -1
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// Test arithmetic shift right by B
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ops[5] = 3'b111;
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A[5] = {{(2**width-2){1'b1}}, 2'b00}; // -4
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C[5] = {{(width-1){1'b0}}, 1'b1}; // 1
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B[5] = {{(2**width-2){1'b0}}, 2'b10}; // 2
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Y_exp[5] = {2**width{1'b1}}; // -1
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error_count = 0;
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$display("Beginning Shifter tests");
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for (integer N = 0; N < $size(ops); ++N) begin
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op = ops[N];
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A_in = A[N];
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B_in = B[N];
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C_in = C[N];
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#1;
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if (Y != Y_exp[N]) begin
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$display("\t\x1b[38;5;9mShifter(%0d) Op 0b%b(0b%b, 0b%b, 0b%b) produced 0b%b but 0b%b was expected\x1b[m", N, op, A_in, B_in, C_in, Y, Y_exp[N]);
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error_count = error_count + 1;
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end
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end
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if (error_count == 0) $display("\x1b[38;5;10mAll Shifter tests passing\x1b[m");
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else $display("\x1b[38;5;9m%0d Shifter test(s) failing\x1b[m", error_count);
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end
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endmodule
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