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FPGA_Uni/Submission/Q3.txt

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// Sumbission for ELEC4720 Assignment 1 Question 3
// Oliver Boutros (c3428958)
// Riley King-Saunders (cc3430382)
`ifndef ASU_H_SV
`define ASU_H_SV
`ifndef SEVEN_SEG_H_SV
`define SEVEN_SEG_H_SV
module seven_seg(input logic [3:0] num, input logic [0:0] rbi_inv, output logic [7:0] segments);
always_comb begin
case (num)
4'b0000: segments = (rbi_inv) ? ~(8'b01111111) : ~(8'b00000000);
4'b0001: segments = ~(8'b00001101);
4'b0010: segments = ~(8'b10110111);
4'b0011: segments = ~(8'b10011111);
4'b0100: segments = ~(8'b11001101);
4'b0101: segments = ~(8'b11011011);
4'b0110: segments = ~(8'b11111011);
4'b0111: segments = ~(8'b00001111);
4'b1000: segments = ~(8'b11111111);
4'b1001: segments = ~(8'b11001111);
4'b1010: segments = ~(8'b11101111);
4'b1011: segments = ~(8'b11111001);
4'b1100: segments = ~(8'b01110011);
4'b1101: segments = ~(8'b10111101);
4'b1110: segments = ~(8'b11110011);
4'b1111: segments = ~(8'b11100011);
default: segments = ~(8'bxxxxxxxx);
endcase
end
endmodule
`endif
module asu #(parameter width = 2)(
input logic [0:0] op,
input logic[2**width-1:0] A, input logic[2**width-1:0] B,
output logic[2**width-1:0] OUT_1, output logic[0:0] COUT, output logic[0:0] OUT_CIN
// Used to switch between demo mode and testbench mode
// TODO: Strip for assignment 2
`ifdef SYNTHESIS
, output logic[7:0] out_seg_1);
`else
);
`endif
logic [2**width-1:0] operand;
always_comb begin
// A + (sub) ? B : -B
// Adds an extra bit to all operands to calculate the carry bit. Not optimal for hardware synthesis
//operand = (B ^ {(2**width){op}});
operand = op == 1'b0 ? B : ~B;
{COUT, OUT_1} = A + operand + {{(2**width-1){1'b0}}, op};
end
// Need to do this outside of the always_comb block because parameter-based bitslicing/indexing isn't supported?
// Cin for final bit in adder to later be xor'ed with COUT to determine if a signed overflow occured for the MIPS architecture
assign OUT_CIN = A[2**width-1] ^ operand[2**width-1] ^ OUT_1[2**width-1];
// Include seven segment visual output for hardware builds only
// TODO: Strip this for assignment 2 outright
`ifdef SYNTHESIS
seven_seg dut(OUT_1, 1'b1, out_seg_1);
`endif
endmodule
`endif
// Testbench
module asu_tb #(width=4)();
logic [0:0] op;
logic [width-1:0] A;
logic [width-1:0] B;
logic [width-1:0] C;
logic [0:0] Cout;
logic [0:0] Cin;
logic [width-1:0] C_exp;
logic [0:0] Cout_exp;
logic [0:0] Cin_exp; // TODO
asu #($clog2(width)) dut(op, A, B, C, Cout, Cin);
integer error_count;
initial begin
error_count = 0;
$display("Beginning ASU tests");
// Test basic addition of 0+1 = 1
op = 1'b0;
A = {width{1'b0}};
B = { {(width-1){1'b0}}, 1'b1};
C_exp = { {(width-1){1'b0}}, 1'b1};
Cout_exp = 1'b0;
Cin_exp = 1'b0;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
// Test underflow from 0-1 = UINTMAX
op = 1'b1;
C_exp = {(width){1'b1}};
Cout_exp = 1'b0;
Cin_exp = 1'b0;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
// Test carry addition of 1+1 = 2
op = 1'b0;
A = { {(width-1){1'b0}}, 1'b1};
B = { {(width-1){1'b0}}, 1'b1};
C_exp = { {(width-2){1'b0}}, 2'b10};
Cout_exp = 1'b0;
Cin_exp = 1'b0;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
// Test overflow from UINTMAX+1 = 0
A = {(width){1'b1}}; // UINTMAX
B = { {(width-1){1'b0}}, 1'b1}; // 1
C_exp = {(width){1'b0}};
Cout_exp = 1'b1;
Cin_exp = 1'b1;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
// Tests INTMAX+1
op = 1'b0;
A = {1'b0, {(width-1){1'b1}}}; // INTMAX
B = {{(width-1){1'b0}}, 1'b1}; // 1
C_exp = {1'b1, {(width-1){1'b0}}}; // -INTMAX
Cin_exp = 1'b1;
Cout_exp = 1'b0;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
op = 1'b0;
A = {1'b1, {(width-1){1'b0}}}; // -INTMAX
B = {1'b1, {(width-1){1'b0}}}; // -INTMAX
C_exp = {width{1'b0}}; // 0
Cin_exp = 1'b0;
Cout_exp = 1'b1;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
op = 1'b1;
A = {1'b0, {(width-1){1'b1}}}; // INTMAX
B = {1'b1, {(width-1){1'b0}}}; // -INTMAX
C_exp = {width{1'b1}}; // -1
Cin_exp = 1'b1;
Cout_exp = 1'b0;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
op = 1'b1;
A = {1'b1, {(width-1){1'b0}}}; // -INTMAX
B = {{(width-1){1'b0}}, 1'b1}; // 1
C_exp = {1'b0, {(width-1){1'b1}}}; // INTMAX
Cin_exp = 1'b0;
Cout_exp = 1'b1;
#1;
if (C != C_exp || Cout != Cout_exp || Cin != Cin_exp || (Cin ^ Cout) != (Cin_exp ^ Cout_exp)) begin
$display("\t\x1b[38;5;9mOp 0b%b(0b%b, 0b%b) produced 0b%b%b_%b but 0b%b%b_%b was expected\x1b[m", op, A, B, Cin, Cout, C, Cin_exp, Cout_exp, C_exp);
error_count = error_count + 1;
end
if (error_count == 0) $display("\x1b[38;5;10mAll ASU tests passing\x1b[m");
else $display("\x1b[38;5;9m%0d ASU test(s) failing\x1b[m", error_count);
end
endmodule