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qemu/int128: add int128_urshift

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Implement an unsigned right shift for Int128 values and add the same
tests cases of int128_rshift in the unit test.

Signed-off-by: Matheus Ferst <matheus.ferst@eldorado.org.br>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220330175932.6995-3-matheus.ferst@eldorado.org.br>
[danielhb: fixed long lines in test_urshift()]
Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
This commit is contained in:
Matheus Ferst 2022-03-30 14:59:26 -03:00 committed by Daniel Henrique Barboza
parent f290a23868
commit 613cf0fcba
2 changed files with 69 additions and 0 deletions
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19
include/qemu/int128.h
View file

@ -83,6 +83,11 @@ static inline Int128 int128_rshift(Int128 a, int n)
return a >> n;
}
static inline Int128 int128_urshift(Int128 a, int n)
{
return (__uint128_t)a >> n;
}
static inline Int128 int128_lshift(Int128 a, int n)
{
return a << n;
@ -299,6 +304,20 @@ static inline Int128 int128_rshift(Int128 a, int n)
}
}
static inline Int128 int128_urshift(Int128 a, int n)
{
uint64_t h = a.hi;
if (!n) {
return a;
}
h = h >> (n & 63);
if (n >= 64) {
return int128_make64(h);
} else {
return int128_make128((a.lo >> n) | ((uint64_t)a.hi << (64 - n)), h);
}
}
static inline Int128 int128_lshift(Int128 a, int n)
{
uint64_t l = a.lo << (n & 63);

50
tests/unit/test-int128.c
View file

@ -206,6 +206,55 @@ static void test_rshift(void)
test_rshift_one(0xFFFE8000U, 0, 0xFFFFFFFFFFFFFFFEULL, 0x8000000000000000ULL);
}
static void __attribute__((__noinline__)) ATTRIBUTE_NOCLONE
test_urshift_one(uint32_t x, int n, uint64_t h, uint64_t l)
{
Int128 a = expand(x);
Int128 r = int128_urshift(a, n);
g_assert_cmpuint(int128_getlo(r), ==, l);
g_assert_cmpuint(int128_gethi(r), ==, h);
}
static void test_urshift(void)
{
test_urshift_one(0x00010000U, 64, 0x0000000000000000ULL,
0x0000000000000001ULL);
test_urshift_one(0x80010000U, 64, 0x0000000000000000ULL,
0x8000000000000001ULL);
test_urshift_one(0x7FFE0000U, 64, 0x0000000000000000ULL,
0x7FFFFFFFFFFFFFFEULL);
test_urshift_one(0xFFFE0000U, 64, 0x0000000000000000ULL,
0xFFFFFFFFFFFFFFFEULL);
test_urshift_one(0x00010000U, 60, 0x0000000000000000ULL,
0x0000000000000010ULL);
test_urshift_one(0x80010000U, 60, 0x0000000000000008ULL,
0x0000000000000010ULL);
test_urshift_one(0x00018000U, 60, 0x0000000000000000ULL,
0x0000000000000018ULL);
test_urshift_one(0x80018000U, 60, 0x0000000000000008ULL,
0x0000000000000018ULL);
test_urshift_one(0x7FFE0000U, 60, 0x0000000000000007ULL,
0xFFFFFFFFFFFFFFE0ULL);
test_urshift_one(0xFFFE0000U, 60, 0x000000000000000FULL,
0xFFFFFFFFFFFFFFE0ULL);
test_urshift_one(0x7FFE8000U, 60, 0x0000000000000007ULL,
0xFFFFFFFFFFFFFFE8ULL);
test_urshift_one(0xFFFE8000U, 60, 0x000000000000000FULL,
0xFFFFFFFFFFFFFFE8ULL);
test_urshift_one(0x00018000U, 0, 0x0000000000000001ULL,
0x8000000000000000ULL);
test_urshift_one(0x80018000U, 0, 0x8000000000000001ULL,
0x8000000000000000ULL);
test_urshift_one(0x7FFE0000U, 0, 0x7FFFFFFFFFFFFFFEULL,
0x0000000000000000ULL);
test_urshift_one(0xFFFE0000U, 0, 0xFFFFFFFFFFFFFFFEULL,
0x0000000000000000ULL);
test_urshift_one(0x7FFE8000U, 0, 0x7FFFFFFFFFFFFFFEULL,
0x8000000000000000ULL);
test_urshift_one(0xFFFE8000U, 0, 0xFFFFFFFFFFFFFFFEULL,
0x8000000000000000ULL);
}
int main(int argc, char **argv)
{
g_test_init(&argc, &argv, NULL);
@ -219,5 +268,6 @@ int main(int argc, char **argv)
g_test_add_func("/int128/int128_ge", test_ge);
g_test_add_func("/int128/int128_gt", test_gt);
g_test_add_func("/int128/int128_rshift", test_rshift);
g_test_add_func("/int128/int128_urshift", test_urshift);
return g_test_run();
}