064360e667
libgcc for boot environment isn't always present and compatible. libgcc is often absent if endianness or bit-size at boot is different from running OS. libgcc may use optimised opcodes that aren't available on boot time. So instead of relying on libgcc shipped with the compiler, supply the functions in GRUB directly. Tests are present to ensure that those replacement functions behave the way compiler expects them to.
157 lines
3.6 KiB
C
157 lines
3.6 KiB
C
/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2015 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[] = {
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0xffffffffffffffffULL, 1, 2, 0, 0x0102030405060708ULL
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};
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/* We're testing shifts, don't replace access to this with a shift. */
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static const grub_uint8_t bitmask[] =
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{ 0x01, 0x02, 0x04, 0x08, 0x10, 0x20, 0x40, 0x80 };
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typedef union {
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grub_uint64_t v64;
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grub_uint8_t v8[8];
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} grub_raw_u64_t;
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static int
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get_bit64 (grub_uint64_t v, int b)
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{
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grub_raw_u64_t vr = { .v64 = v };
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grub_uint8_t *p = vr.v8;
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if (b >= 64)
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return 0;
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#ifdef GRUB_CPU_WORDS_BIGENDIAN
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p += 7 - b / 8;
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#else
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p += b / 8;
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#endif
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return !!(*p & bitmask[b % 8]);
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}
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static grub_uint64_t
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set_bit64 (grub_uint64_t v, int b)
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{
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grub_raw_u64_t vr = { .v64 = v };
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grub_uint8_t *p = vr.v8;
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if (b >= 64)
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return v;
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#ifdef GRUB_CPU_WORDS_BIGENDIAN
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p += 7 - b / 8;
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#else
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p += b / 8;
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#endif
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*p |= bitmask[b % 8];
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return vr.v64;
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}
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static grub_uint64_t
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left_shift64 (grub_uint64_t v, int s)
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{
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grub_uint64_t r = 0;
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int i;
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for (i = 0; i + s < 64; i++)
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if (get_bit64 (v, i))
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r = set_bit64 (r, i + s);
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return r;
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}
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static grub_uint64_t
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right_shift64 (grub_uint64_t v, int s)
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{
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grub_uint64_t r = 0;
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int i;
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for (i = s; i < 64; i++)
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if (get_bit64 (v, i))
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r = set_bit64 (r, i - s);
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return r;
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}
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static grub_uint64_t
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arithmetic_right_shift64 (grub_uint64_t v, int s)
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{
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grub_uint64_t r = 0;
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int i;
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for (i = s; i < 64; i++)
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if (get_bit64 (v, i))
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r = set_bit64 (r, i - s);
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if (get_bit64 (v, 63))
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for (i -= s; i < 64; i++)
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r = set_bit64 (r, i);
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return r;
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}
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static void
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test64 (grub_uint64_t v)
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{
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int i;
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for (i = 0; i < 64; i++)
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{
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grub_test_assert ((v << i) == left_shift64 (v, i),
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"lshift wrong: 0x%llx << %d: 0x%llx, 0x%llx",
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(long long) v, i,
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(long long) (v << i), (long long) left_shift64 (v, i));
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grub_test_assert ((v >> i) == right_shift64 (v, i),
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"rshift wrong: 0x%llx >> %d: 0x%llx, 0x%llx",
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(long long) v, i,
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(long long) (v >> i), (long long) right_shift64 (v, i));
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grub_test_assert ((((grub_int64_t) v) >> i) == (grub_int64_t) arithmetic_right_shift64 (v, i),
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"arithmetic rshift wrong: ((grub_int64_t) 0x%llx) >> %d: 0x%llx, 0x%llx",
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(long long) v, i,
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(long long) (((grub_int64_t) v) >> i), (long long) arithmetic_right_shift64 (v, i));
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}
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}
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static void
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test_all(grub_uint64_t a)
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{
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test64 (a);
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}
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static void
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shift_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]);
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}
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for (i = 0; i < 4000; 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);
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test_all (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 (shift_test, shift_test);
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