Add first bigint test

Signed-off-by: Davide Bettio <davide@uninstall.it>

Author: bettio

tests/erlang_tests/CMakeLists.txt

@@ -520,6 +520,8 @@ compile_erlang(test_raw_raise)
 
 compile_erlang(test_ets)
 
+compile_erlang(bigint)
+
 add_custom_target(erlang_test_modules DEPENDS
     code_load_files
 
@@ -1004,4 +1006,5 @@ add_custom_target(erlang_test_modules DEPENDS
     test_raw_raise.beam
 
     test_ets.beam
+    bigint.beam
 )

tests/erlang_tests/bigint.erl

@@ -0,0 +1,107 @@
+%
+% This file is part of AtomVM.
+%
+% Copyright 2025 Davide Bettio <davide@uninstall.it>
+%
+% Licensed under the Apache License, Version 2.0 (the "License");
+% you may not use this file except in compliance with the License.
+% You may obtain a copy of the License at
+%
+%    http://www.apache.org/licenses/LICENSE-2.0
+%
+% Unless required by applicable law or agreed to in writing, software
+% distributed under the License is distributed on an "AS IS" BASIS,
+% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+% See the License for the specific language governing permissions and
+% limitations under the License.
+%
+% SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later
+%
+
+-module(bigint).
+-export([start/0, mul/2, shrink/0, pow/2, twice/1, fact/1, get_machine_atom/0, expect_overflow/1]).
+
+start() ->
+    test_mul().
+
+test_mul() ->
+    Expected_INT64_MIN = ?MODULE:pow(-2, 63),
+    Expected_INT64_MIN = ?MODULE:shrink(),
+    A = ?MODULE:mul(16#10101010CAFECAFE, 16#AABB),
+    Square = ?MODULE:mul(A, A),
+    <<"2559181265480533323615999200984578944503596644">> = erlang:integer_to_binary(Square),
+
+    B = ?MODULE:mul(16#10101010CAFECAFE, 16#AABBCCDD),
+    C = ?MODULE:mul(-(16#17322539CAFECAFE), 16#A2CBFCDD),
+    D = ?MODULE:mul(16#19171411CAFECAFE, -(16#AF8BCCFD)),
+    E = ?MODULE:mul(-(16#34143919CAFECAFE), -(16#8C8BCCED)),
+
+    F = ?MODULE:mul(16#34143919CAFECAFE, 16#1234CAFE5678CAFE),
+    G = ?MODULE:mul(-(16#34143919CAFECAFE), 16#1234CAFE5678CAFE),
+    H = ?MODULE:twice(?MODULE:twice(G)),
+
+    <<"3315418878780451855276287302">> = erlang:integer_to_binary(B),
+    <<"-4565164722186152120719328582">> = erlang:integer_to_binary(C),
+    <<"-5324687047716540217489556742">> = erlang:integer_to_binary(D),
+    <<"8848732046695083633938421030">> = erlang:integer_to_binary(E),
+    <<"4923137486833276011090373091921613828">> = erlang:integer_to_binary(F),
+    <<"-4923137486833276011090373091921613828">> = erlang:integer_to_binary(G),
+    <<"-19692549947333104044361492367686455312">> = erlang:integer_to_binary(H),
+
+    0 = ?MODULE:mul(0, E),
+    0 = ?MODULE:mul(0, H),
+
+    INT255_MIN = ?MODULE:pow(-2, 255),
+    ok = ?MODULE:expect_overflow(fun() -> ?MODULE:twice(INT255_MIN) end),
+    ok = ?MODULE:expect_overflow(fun() -> ?MODULE:mul(INT255_MIN, -1) end),
+    ok = ?MODULE:expect_overflow(fun() -> ?MODULE:mul(-1, INT255_MIN) end),
+    <<"-57896044618658097711785492504343953926634992332820282019728792003956564819968">> = erlang:integer_to_binary(
+        INT255_MIN
+    ),
+    erlang:display(INT255_MIN),
+
+    Fact55 = ?MODULE:fact(55),
+    <<"12696403353658275925965100847566516959580321051449436762275840000000000000">> = erlang:integer_to_binary(
+        Fact55
+    ),
+
+    ?MODULE:mul(0, INT255_MIN) + ?MODULE:mul(INT255_MIN, 0).
+
+mul(A, B) ->
+    A * B.
+
+shrink() ->
+    S1 = ?MODULE:mul(4611686018427387904, 2),
+    S2 = ?MODULE:mul(-1, S1),
+    S2.
+
+pow(_A, 0) ->
+    1;
+pow(A, N) ->
+    A * pow(A, N - 1).
+
+twice(N) ->
+    2 * N.
+
+fact(0) ->
+    1;
+fact(N) when N rem 2 == 0 ->
+    N * fact(N - 1);
+fact(N) when N rem 2 == 1 ->
+    fact(N - 1) * N.
+
+expect_overflow(OvfFun) ->
+    Machine = ?MODULE:get_machine_atom(),
+    try {Machine, OvfFun()} of
+        {beam, I} when is_integer(I) -> ok;
+        {atomvm, Result} -> {unexpected_result, Result}
+    catch
+        error:overflow -> ok;
+        _:E -> {unexpected_error, E}
+    end.
+
+get_machine_atom() ->
+    case erlang:system_info(machine) of
+        "BEAM" -> beam;
+        _ -> atomvm
+    end.

tests/test.c

@@ -578,6 +578,8 @@ struct Test tests[] = {
 
     TEST_CASE(test_ets),
 
+    TEST_CASE(bigint),
+
     // TEST CRASHES HERE: TEST_CASE(memlimit),
 
     { NULL, 0, false, false }