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module top;
integer x, y, z;
task check;
input integer a, b, c;
assert (x == a);
assert (y == b);
assert (z == c);
endtask
always_comb begin
x = 0; y = 0; z = 0;
check(0, 0, 0);
// post-increment/decrement statements
x++;
check(1, 0, 0);
(* bar *) y (* foo *) ++;
check(1, 1, 0);
z--;
check(1, 1, -1);
(* bar *) z (* foo *) --;
check(1, 1, -2);
// pre-increment/decrement statements are equivalent
++z;
check(1, 1, -1);
(* bar *) ++ (* foo *) z;
check(1, 1, 0);
--x;
check(0, 1, 0);
(* bar *) -- (* foo *) y;
check(0, 0, 0);
// procedural pre-increment/decrement expressions
z = ++x;
check(1, 0, 1);
z = ++ (* foo *) x;
check(2, 0, 2);
y = --x;
check(1, 1, 2);
y = -- (* foo *) x;
// procedural post-increment/decrement expressions
// TODO: support attributes on post-increment/decrement
check(0, 0, 2);
y = x++;
check(1, 0, 2);
y = x--;
check(0, 1, 2);
// procedural assignment expressions
x = (y = (z = 99) + 1) + 1;
check(101, 100, 99);
x = (y *= 2);
check(200, 200, 99);
x = (z >>= 2) * 4;
check(96, 200, 24);
y = (z >>= 1'sb1) * 2; // shift is implicitly cast to unsigned
check(96, 24, 12);
// check width of post-increment expressions
z = (y = 0);
begin
byte w;
w = 0;
x = {1'b1, ++w};
check(257, 0, 0);
assert (w == 1);
x = {2'b10, w++};
check(513, 0, 0);
assert (w == 2);
end
end
endmodule
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