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[RFC PATCH 2/8] qemu/int128: add int128_urshift
From: |
matheus . ferst |
Subject: |
[RFC PATCH 2/8] qemu/int128: add int128_urshift |
Date: |
Wed, 30 Mar 2022 14:59:26 -0300 |
From: Matheus Ferst <matheus.ferst@eldorado.org.br>
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>
---
include/qemu/int128.h | 19 +++++++++++++++++++
tests/unit/test-int128.c | 32 ++++++++++++++++++++++++++++++++
2 files changed, 51 insertions(+)
diff --git a/include/qemu/int128.h b/include/qemu/int128.h
index 2a19558ac6..ca32b0b276 100644
--- a/include/qemu/int128.h
+++ b/include/qemu/int128.h
@@ -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 (__uint128_t)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);
diff --git a/tests/unit/test-int128.c b/tests/unit/test-int128.c
index b86a3c76e6..ae0f552193 100644
--- a/tests/unit/test-int128.c
+++ b/tests/unit/test-int128.c
@@ -206,6 +206,37 @@ 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 +250,6 @@ 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();
}
--
2.25.1
- [RFC PATCH 0/8] Alternative softfloat 128-bit integer support, matheus . ferst, 2022/03/30
- [RFC PATCH 1/8] qemu/int128: avoid undefined behavior in int128_lshift, matheus . ferst, 2022/03/30
- [RFC PATCH 2/8] qemu/int128: add int128_urshift,
matheus . ferst <=
- [RFC PATCH 3/8] softfloat: add uint128_to_float128, matheus . ferst, 2022/03/30
- [RFC PATCH 4/8] softfloat: add int128_to_float128, matheus . ferst, 2022/03/30
- [RFC PATCH 5/8] softfloat: add float128_to_uint128, matheus . ferst, 2022/03/30
- [RFC PATCH 6/8] softfloat: add float128_to_int128, matheus . ferst, 2022/03/30
- [RFC PATCH 7/8] target/ppc: implement xscv[su]qqp, matheus . ferst, 2022/03/30