f034fab620
Previously we supplied only unsigned divisions on platforms that need software division. Yet compiler may itself use a signed division. A typical example would be a difference between 2 pointers which involves division by object size.
189 lines
6.5 KiB
C
189 lines
6.5 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2013 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/test.h>
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#include <grub/dl.h>
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#include <grub/misc.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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static grub_uint64_t vectors[][2] = {
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{ 0xffffffffffffffffULL, 1},
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{ 1, 0xffffffffffffffffULL},
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{ 0xffffffffffffffffULL, 0xffffffffffffffffULL},
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{ 1, 1 },
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{ 2, 1 }
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};
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static void
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test32 (grub_uint32_t a, grub_uint32_t b)
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{
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grub_uint64_t q, r;
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if (b == 0)
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return;
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q = grub_divmod64 (a, b, &r);
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grub_test_assert (r < b, "remainder is larger than dividend: 0x%llx %% 0x%llx = 0x%llx",
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(long long) a, (long long) b, (long long) r);
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grub_test_assert (q * b + r == a, "division doesn't satisfy base property: 0x%llx * 0x%llx + 0x%llx != 0x%llx", (long long) q, (long long) b, (long long) r,
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(long long) a);
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/* Overflow check. */
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grub_test_assert ((q >> 32) == 0,
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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grub_test_assert ((r >> 32) == 0,
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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/* q * b + r is at most:
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0xffffffff * 0xffffffff + 0xffffffff = 0xffffffff00000000
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so no overflow
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*/
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grub_test_assert (q == (a / b),
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"C compiler division failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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grub_test_assert (r == (a % b),
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"C compiler modulo failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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}
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static void
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test64 (grub_uint64_t a, grub_uint64_t b)
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{
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grub_uint64_t q, r;
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grub_uint64_t x1, x2;
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q = grub_divmod64 (a, b, &r);
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grub_test_assert (r < b, "remainder is larger than dividend: 0x%llx %% 0x%llx = 0x%llx",
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(long long) a, (long long) b, (long long) r);
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grub_test_assert (q * b + r == a, "division doesn't satisfy base property: 0x%llx * 0x%llx + 0x%llx != 0x%llx", (long long) q, (long long) b, (long long) r,
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(long long) a);
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/* Overflow checks. */
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grub_test_assert ((q >> 32) * (b >> 32) == 0,
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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x1 = (q >> 32) * (b & 0xffffffff);
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grub_test_assert (x1 < (1LL << 32),
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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x1 <<= 32;
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x2 = (b >> 32) * (q & 0xffffffff);
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grub_test_assert (x2 < (1LL << 32),
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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x2 <<= 32;
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grub_test_assert (x1 <= ~x2,
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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x1 += x2;
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x2 = (q & 0xffffffff) * (b & 0xffffffff);
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grub_test_assert (x1 <= ~x2,
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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x1 += x2;
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grub_test_assert (x1 <= ~r,
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"division overflow in 0x%llx, 0x%llx", (long long) a, (long long) b);
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x1 += r;
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grub_test_assert (a == x1,
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"division overflow test failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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#if GRUB_TARGET_SIZEOF_VOID_P == 8
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grub_test_assert (q == (a / b),
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"C compiler division failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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grub_test_assert (r == (a % b),
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"C compiler modulo failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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#endif
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}
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static grub_int64_t
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abs64(grub_int64_t a)
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{
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return a > 0 ? a : -a;
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}
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static void
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test32s (grub_int32_t a, grub_int32_t b)
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{
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grub_int64_t q, r;
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if (b == 0)
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return;
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q = grub_divmod64s (a, b, &r);
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grub_test_assert (a > 0 ? r >= 0 : r <= 0, "remainder sign mismatch: %lld %% %lld = %lld",
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(long long) a, (long long) b, (long long) r);
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grub_test_assert (((a > 0) == (b > 0)) ? q >= 0 : q <= 0, "quotient sign mismatch: %lld / %lld = %lld",
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(long long) a, (long long) b, (long long) q);
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grub_test_assert (abs64(r) < abs64(b), "remainder is larger than dividend: %lld %% %lld = %lld",
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(long long) a, (long long) b, (long long) r);
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grub_test_assert (q * b + r == a, "division doesn't satisfy base property: %lld * %lld + %lld != %lld", (long long) q, (long long) b, (long long) r,
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(long long) a);
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if (0) { grub_test_assert (q == (a / b),
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"C compiler division failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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grub_test_assert (r == (a % b),
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"C compiler modulo failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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}
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}
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static void
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test64s (grub_int64_t a, grub_int64_t b)
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{
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grub_int64_t q, r;
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q = grub_divmod64s (a, b, &r);
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grub_test_assert (a > 0 ? r >= 0 : r <= 0, "remainder sign mismatch: %lld %% %lld = %lld",
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(long long) a, (long long) b, (long long) r);
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grub_test_assert (((a > 0) == (b > 0)) ? q >= 0 : q <= 0, "quotient sign mismatch: %lld / %lld = %lld",
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(long long) a, (long long) b, (long long) q);
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grub_test_assert (abs64(r) < abs64(b), "remainder is larger than dividend: %lld %% %lld = %lld",
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(long long) a, (long long) b, (long long) r);
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grub_test_assert (q * b + r == a, "division doesn't satisfy base property: 0x%llx * 0x%llx + 0x%llx != 0x%llx", (long long) q, (long long) b, (long long) r,
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(long long) a);
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#if GRUB_TARGET_SIZEOF_VOID_P == 8
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grub_test_assert (q == (a / b),
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"C compiler division failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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grub_test_assert (r == (a % b),
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"C compiler modulo failure in 0x%llx, 0x%llx", (long long) a, (long long) b);
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#endif
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}
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static void
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test_all(grub_uint64_t a, grub_uint64_t b)
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{
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test64 (a, b);
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test32 (a, b);
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test64s (a, b);
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test32s (a, b);
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test64s (a, -b);
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test32s (a, -b);
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test64s (-a, b);
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test32s (-a, b);
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test64s (-a, -b);
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test32s (-a, -b);
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}
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static void
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div_test (void)
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{
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grub_uint64_t a = 404, b = 7;
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grub_size_t i;
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for (i = 0; i < ARRAY_SIZE (vectors); i++)
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{
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test_all (vectors[i][0], vectors[i][1]);
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}
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for (i = 0; i < 40000; i++)
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{
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a = 17 * a + 13 * b;
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b = 23 * a + 29 * b;
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if (b == 0)
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b = 1;
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if (a == 0)
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a = 1;
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test_all (a, b);
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}
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}
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/* Register example_test method as a functional test. */
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GRUB_FUNCTIONAL_TEST (div_test, div_test);
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