Implemented ALU test cases for all operations. Added ALU testbench to active testing. Fixed bug where alu_flags module argument was defined as a 2-element logic array output rather than a 2-bit logic output
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+205
-21
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+17
-12
@@ -1,3 +1,6 @@
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`ifndef ALU_H_SV
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`define ALU_H_SV
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`include "asu.sv"
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`include "lu.sv"
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@@ -5,8 +8,9 @@
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// flags[1:1] = Overflow
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module alu #(parameter width=2)(input logic [3:0] op,
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input logic [2**width-1:0] A, input logic [2**width-1:0] B,
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output logic [2**width-1:0] OUT_1, output logic flags[1:0]);
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output logic [2**width-1:0] OUT_1, output logic[1:0] flags);
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logic [0:0] asu_op;
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logic [2**width-1:0] asu_out;
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logic [1:0] asu_flags;
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asu #(width) adder_unit(asu_op[op[1]], A, B, asu_out, asu_flags[0], asu_flags[1]);
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@@ -16,17 +20,18 @@ module alu #(parameter width=2)(input logic [3:0] op,
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always_comb begin
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case (op)
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2'b0000: begin OUT_1 = asu_out; flags = asu_flags; end
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2'b0001: begin OUT_1 = asu_out; flags = asu_flags; end
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2'b0010: begin OUT_1 = asu_out; flags = asu_flags; end
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2'b0011: begin OUT_1 = asu_out; flags = asu_flags; end
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2'b0100: OUT_1 = lu_out;
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2'b0101: OUT_1 = lu_out;
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2'b0110: OUT_1 = lu_out;
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2'b0111: OUT_1 = lu_out;
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2'b1010: OUT_1 = (asu_out[2**width-1] ^ asu_flags[1]);
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2'b1011: OUT_1 = ~asu_flags[0];
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default: '0;
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4'b0000: begin OUT_1 = asu_out; flags = asu_flags; end
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4'b0001: begin OUT_1 = asu_out; flags = asu_flags; end
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4'b0010: begin OUT_1 = asu_out; flags = asu_flags; end
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4'b0011: begin OUT_1 = asu_out; flags = asu_flags; end
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4'b0100: OUT_1 = lu_out;
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4'b0101: OUT_1 = lu_out;
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4'b0110: OUT_1 = lu_out;
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4'b0111: OUT_1 = lu_out;
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4'b1010: OUT_1 = (asu_out[2**width-1] ^ asu_flags[1]) & {{(width-1){1'b0}}, 1'b1};
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4'b1011: OUT_1 = ~asu_flags[0] & {{(width-1){1'b0}}, 1'b1};
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default: OUT_1 = {(2**width){1'b0}};
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endcase
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end
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endmodule
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`endif
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+187
-9
@@ -1,33 +1,211 @@
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`#include "alu.sv"
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`include "alu.sv"
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module alu_tb #(width=2)();
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localparam bitwidth = 2**width;
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// Guard against future me by testing the tests
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generate
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if (bitwidth < 4) begin : param_asserts
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initial begin
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$fatal(1, "Can not instantiate an ALU testbench with less than 4 bits (n=2)");
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end
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end
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endgenerate
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logic [3:0] op_in;
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logic [2**width-1:0] A_in;
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logic [2**width-1:0] B_in;
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logic [2**width-1:0] Y_out;
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logic [1:0] flags_out;
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logic [3:0] ops[1];
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logic [2**width-1:0] A_cases[$size(ops)];
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logic [2**width-1:0] B_cases[$size(ops)];
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logic [2**width-1:0] Y_exp[$size(ops)];
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logic [1:0] flags_exp[$size(ops)];
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localparam int NUM_TESTS = 28;
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logic [3:0] ops[NUM_TESTS];
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logic [2**width-1:0] A_cases[NUM_TESTS];
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logic [2**width-1:0] B_cases[NUM_TESTS];
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logic [2**width-1:0] Y_exp[NUM_TESTS];
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logic [1:0] flags_exp[NUM_TESTS];
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alu #(width)(op_in, A_in, B_in, Y_out, flags_out);
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alu #(width) dut (op_in, A_in, B_in, Y_out, flags_out);
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integer error_count;
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initial begin
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ops[0] = 4'b0000; // sadd
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A_in[0] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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B_in[0] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[0] = {{(bitwidth-2){1'b0}}, 2'b10}; // 0
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flags_exp[0] = {2'b00}; // ~Cout, ~Overflow
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ops[1] = 4'b0000; // sadd
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A_in[1] = {bitwidth{1'b1}}; // UINTMAX
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B_in[1] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[1] = {bitwidth{1'b0}}; // 0
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flags_exp[1] = {2'b01}; // Cout, ~Overflow
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ops[2] = 4'b0000; // sadd
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A_in[2] = {{1'b0}, {(bitwidth-1){1'b1}}}; // INTMAX
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B_in[2] = {{(bitwidth-1){1'b0}} , {1'b1}}; // 1
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Y_exp[2] = {{1'b1}, {(bitwidth-1){1'b0}} };// -INTMAX
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flags_exp[2] = {2'b10}; // ~Cout, Overflow
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ops[3] = 4'b0000; // sadd
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A_in[3] = {{1'b1}, {(bitwidth-1){1'b0}}}; // -INTMAX
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B_in[3] = {{1'b1}, {(bitwidth-1){1'b0}}}; // -INTMAX
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Y_exp[3] = {bitwidth{1'b0}}; // 0
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flags_exp[3] = {2'b11}; // Cout, Overflow
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ops[4] = 4'b0001; // uadd
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A_in[4] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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B_in[4] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[4] = {{(bitwidth-2){1'b0}}, 2'b10}; // 0
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flags_exp[4] = {2'b00}; // ~Cout, ~Overflow
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ops[5] = 4'b0001; // uadd
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A_in[5] = {bitwidth{1'b1}}; // UINTMAX
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B_in[5] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[5] = {bitwidth{1'b0}}; // 0
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flags_exp[5] = {2'b01}; // Cout, ~Overflow
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ops[6] = 4'b0001; // uadd
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A_in[6] = {{1'b0}, {(bitwidth-1){1'b1}}}; // INTMAX
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B_in[6] = {{(bitwidth-1){1'b0}} , {1'b1}}; // 1
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Y_exp[6] = {{1'b1}, {(bitwidth-1){1'b0}} };// -INTMAX
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flags_exp[6] = {2'b10}; // ~Cout, Overflow
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ops[7] = 4'b0001; // uadd
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A_in[7] = {{1'b1}, {(bitwidth-1){1'b0}}}; // -INTMAX
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B_in[7] = {{1'b1}, {(bitwidth-1){1'b0}}}; // -INTMAX
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Y_exp[7] = {bitwidth{1'b0}}; // 0
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flags_exp[7] = {2'b11}; // Cout, Overflow
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ops[8] = 4'b0010; // ssub
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A_in[8] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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B_in[8] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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Y_exp[8] = {bitwidth{1'b1}}; // -1
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flags_exp[8] = {2'b00}; // ~Cout, ~Overflow
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ops[9] = 4'b0010; // ssub
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A_in[9] = {1'b0, {(bitwidth-1){1'b1}}}; // INTMAX
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B_in[9] = {{(bitwidth-1){1'b0}}, 1'b1}; // -1
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Y_exp[9] = {1'b1, {(bitwidth-1){1'b0}}}; // -INTMAX
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flags_exp[9] = {2'b10}; // ~Cout, Overflow
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ops[10] = 4'b0010; // ssub
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A_in[10] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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B_in[10] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[10] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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flags_exp[10] = {2'b01}; // Cout, ~Overflow
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ops[11] = 4'b0010; // ssub
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A_in[11] = {1'b1, {(bitwidth-1){1'b0}}}; // -INTMAX
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B_in[11] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[11] = {1'b0, {(bitwidth-1){1'b1}}}; // INTMAX
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flags_exp[11] = {2'b11}; // Cout, Overflow
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ops[12] = 4'b0011; // ssub
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A_in[12] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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B_in[12] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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Y_exp[12] = {bitwidth{1'b1}}; // -1
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flags_exp[12] = {2'b00}; // ~Cout, ~Overflow
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ops[13] = 4'b0011; // ssub
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A_in[13] = {1'b0, {(bitwidth-1){1'b1}}}; // INTMAX
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B_in[13] = {{(bitwidth-1){1'b0}}, 1'b1}; // -1
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Y_exp[13] = {1'b1, {(bitwidth-1){1'b0}}}; // -INTMAX
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flags_exp[13] = {2'b10}; // ~Cout, Overflow
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ops[14] = 4'b0011; // ssub
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A_in[14] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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B_in[14] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[14] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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flags_exp[14] = {2'b01}; // Cout, ~Overflow
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ops[15] = 4'b0011; // ssub
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A_in[15] = {1'b1, {(bitwidth-1){1'b0}}}; // -INTMAX
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B_in[15] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[15] = {1'b0, {(bitwidth-1){1'b1}}}; // INTMAX
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flags_exp[15] = {2'b11}; // Cout, Overflow
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ops[16] = 4'b0100; // and
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A_in[16] = {{(bitwidth-4){1'b0}}, 4'b1100}; // c
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B_in[16] = {{(bitwidth-4){1'b0}}, 4'b1010}; // a
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Y_exp[16] = {{(bitwidth-4){1'b0}}, 4'b1000}; // 8
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flags_exp[16] = {2'bxx}; // Don't care
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ops[17] = 4'b0101; // or
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A_in[17] = {{(bitwidth-4){1'b0}}, 4'b1100}; // c
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B_in[17] = {{(bitwidth-4){1'b0}}, 4'b1010}; // a
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Y_exp[17] = {{(bitwidth-4){1'b0}}, 4'b1110}; // e
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flags_exp[17] = {2'bxx}; // Don't care
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ops[18] = 4'b0110; // xor
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A_in[18] = {{(bitwidth-4){1'b0}}, 4'b1100}; // c
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B_in[18] = {{(bitwidth-4){1'b0}}, 4'b1010}; // a
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Y_exp[18] = {{(bitwidth-4){1'b0}}, 4'b0110}; // 6
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flags_exp[18] = {2'bxx}; // Don't care
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ops[19] = 4'b0111; // nor
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A_in[19] = {{(bitwidth-4){1'b0}}, 4'b1100}; // c
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B_in[19] = {{(bitwidth-4){1'b0}}, 4'b1010}; // a
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Y_exp[19] = {{(bitwidth-4){1'b0}}, 4'b0001}; // 1
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flags_exp[19] = {2'bxx}; // Don't care
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ops[20] = 4'b1010; // sslt: 1 < 2 (No overflow)
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A_in[20] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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B_in[20] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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Y_exp[20] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1 (True)
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flags_exp[20] = {2'b00}; // ~Cout, ~Overflow
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ops[21] = 4'b1010; // sslt: 2 < 1 (No overflow)
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A_in[21] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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B_in[21] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[21] = {bitwidth{1'b0}}; // 0 (False)
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flags_exp[21] = {2'b10}; // Cout, ~Overflow
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ops[22] = 4'b1010; // sslt: -INTMAX < 1 (Overflow test)
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A_in[22] = {1'b1, {(bitwidth-1){1'b0}}}; // -INTMAX
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B_in[22] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[22] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1 (True)
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flags_exp[22] = {2'b11}; // Cout, Overflow
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ops[23] = 4'b1010; // sslt: INTMAX < -1 (Overflow test)
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A_in[23] = {1'b0, {(bitwidth-1){1'b1}}}; // INTMAX
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B_in[23] = {bitwidth{1'b1}}; // -1
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Y_exp[23] = {bitwidth{1'b0}}; // 0 (False)
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flags_exp[23] = {2'b01}; // ~Cout, Overflow
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ops[24] = 4'b1011; // uslt: 1 < 2
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A_in[24] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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B_in[24] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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Y_exp[24] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1 (True)
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flags_exp[24] = {2'b00}; // ~Cout, ~Overflow
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ops[25] = 4'b1011; // uslt: 2 < 1
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A_in[25] = {{(bitwidth-2){1'b0}}, 2'b10}; // 2
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B_in[25] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[25] = {bitwidth{1'b0}}; // 0 (False)
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flags_exp[25] = {2'b10}; // Cout, ~Overflow
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ops[26] = 4'b1011; // uslt: 1 < UINTMAX
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A_in[26] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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B_in[26] = {bitwidth{1'b1}}; // UINTMAX
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Y_exp[26] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1 (True)
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flags_exp[26] = {2'b00}; // ~Cout, ~Overflow
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ops[27] = 4'b1011; // uslt: UINTMAX < 1
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A_in[27] = {bitwidth{1'b1}}; // UINTMAX
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B_in[27] = {{(bitwidth-1){1'b0}}, 1'b1}; // 1
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Y_exp[27] = {bitwidth{1'b0}}; // 0 (False)
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flags_exp[27] = {2'b10}; // Cout, ~Overflow
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error_count = 0;
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$display("Beginning ALU tests");
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for (integer N = 0; N < $size(ops); ++N) begin
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op = ops[N];
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op_in = ops[N];
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A_in = A_cases[N];
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B_in = B_cases[N];
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#1;
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if (Y_out != Y_exp[N]) begin
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$display("\t\x1b[38;5;9mALU Instruction 0b%b produced 0b%b_%b but 0b%b_%b was expected\x1b[m", op, flags_out, Y_out, flags_exp[N], Y_exp[N]);
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$display("\t\x1b[38;5;9m[%0d] ALU Instruction 0b%b produced 0b%b_%b but 0b%b_%b was expected\x1b[m", N, op_in, flags_out, Y_out, flags_exp[N], 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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@@ -3,3 +3,4 @@
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`include "tests/asu_tb.sv"
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`include "tests/instruction_classifier_tb.sv"
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`include "tests/shifter_tb.sv"
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`include "tests/alu_tb.sv"
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