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const addv = @import("addo.zig");
const builtin = @import("builtin");
const std = @import("std");
const testing = std.testing;
const math = std.math;
fn test__addoti4(a: i128, b: i128) !void {
var result_ov: c_int = undefined;
var expected_ov: c_int = undefined;
const result = addv.__addoti4(a, b, &result_ov);
const expected: i128 = simple_addoti4(a, b, &expected_ov);
try testing.expectEqual(expected, result);
try testing.expectEqual(expected_ov, result_ov);
}
fn simple_addoti4(a: i128, b: i128, overflow: *c_int) i128 {
overflow.* = 0;
const min: i128 = math.minInt(i128);
const max: i128 = math.maxInt(i128);
if (((a > 0) and (b > max - a)) or
((a < 0) and (b < min - a)))
overflow.* = 1;
return a +% b;
}
test "addoti4" {
if (builtin.zig_backend == .stage2_aarch64) return error.SkipZigTest;
const min: i128 = math.minInt(i128);
const max: i128 = math.maxInt(i128);
var i: i128 = 1;
while (i < max) : (i *|= 2) {
try test__addoti4(i, i);
try test__addoti4(-i, -i);
try test__addoti4(i, -i);
try test__addoti4(-i, i);
}
// edge cases
// 0 + 0 = 0
// MIN + MIN overflow
// MAX + MAX overflow
// 0 + MIN MIN
// 0 + MAX MAX
// MIN + 0 MIN
// MAX + 0 MAX
// MIN + MAX -1
// MAX + MIN -1
try test__addoti4(0, 0);
try test__addoti4(min, min);
try test__addoti4(max, max);
try test__addoti4(0, min);
try test__addoti4(0, max);
try test__addoti4(min, 0);
try test__addoti4(max, 0);
try test__addoti4(min, max);
try test__addoti4(max, min);
// derived edge cases
// MIN+1 + MIN overflow
// MAX-1 + MAX overflow
// 1 + MIN = MIN+1
// -1 + MIN overflow
// -1 + MAX = MAX-1
// +1 + MAX overflow
// MIN + 1 = MIN+1
// MIN + -1 overflow
// MAX + 1 overflow
// MAX + -1 = MAX-1
try test__addoti4(min + 1, min);
try test__addoti4(max - 1, max);
try test__addoti4(1, min);
try test__addoti4(-1, min);
try test__addoti4(-1, max);
try test__addoti4(1, max);
try test__addoti4(min, 1);
try test__addoti4(min, -1);
try test__addoti4(max, -1);
try test__addoti4(max, 1);
}
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