We are about to allow passing Int128 to/from tcg helper functions,
but libffi doesn't support __int128_t, so use the structure.
In order for atomic128.h to continue working, we must provide
a mechanism to frob between real __int128_t and the structure.
Provide a new union, Int128Alias, for this. We cannot modify
Int128 itself, as any changed alignment would also break libffi.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
include/qemu/atomic128.h | 29 +++++++++++++++++++++------
include/qemu/int128.h | 25 +++++++++++++++++++++---
util/int128.c | 42 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 87 insertions(+), 9 deletions(-)
diff --git a/include/qemu/atomic128.h b/include/qemu/atomic128.h
index adb9a1a260..d0ba0b9c65 100644
--- a/include/qemu/atomic128.h
+++ b/include/qemu/atomic128.h
@@ -44,13 +44,23 @@
#if defined(CONFIG_ATOMIC128)
static inline Int128 atomic16_cmpxchg(Int128 *ptr, Int128 cmp, Int128 new)
{
- return qatomic_cmpxchg__nocheck(ptr, cmp, new);
+ Int128Alias r, c, n;
+
+ c.s = cmp;
+ n.s = new;
+ r.i = qatomic_cmpxchg__nocheck((__int128_t *)ptr, c.i, n.i);
+ return r.s;
}
# define HAVE_CMPXCHG128 1
#elif defined(CONFIG_CMPXCHG128)
static inline Int128 atomic16_cmpxchg(Int128 *ptr, Int128 cmp, Int128 new)
{
- return __sync_val_compare_and_swap_16(ptr, cmp, new);
+ Int128Alias r, c, n;
+
+ c.s = cmp;
+ n.s = new;
+ r.i = __sync_val_compare_and_swap_16((__int128_t *)ptr, c.i, n.i);
+ return r.s;
}
# define HAVE_CMPXCHG128 1
#elif defined(__aarch64__)
@@ -89,12 +99,18 @@ Int128 QEMU_ERROR("unsupported atomic")
#if defined(CONFIG_ATOMIC128)
static inline Int128 atomic16_read(Int128 *ptr)
{
- return qatomic_read__nocheck(ptr);
+ Int128Alias r;
+
+ r.i = qatomic_read__nocheck((__int128_t *)ptr);
+ return r.s;
}
static inline void atomic16_set(Int128 *ptr, Int128 val)
{
- qatomic_set__nocheck(ptr, val);
+ Int128Alias v;
+
+ v.s = val;
+ qatomic_set__nocheck((__int128_t *)ptr, v.i);
}
# define HAVE_ATOMIC128 1
@@ -132,7 +148,8 @@ static inline void atomic16_set(Int128 *ptr, Int128 val)
static inline Int128 atomic16_read(Int128 *ptr)
{
/* Maybe replace 0 with 0, returning the old value. */
- return atomic16_cmpxchg(ptr, 0, 0);
+ Int128 z = int128_make64(0);
+ return atomic16_cmpxchg(ptr, z, z);
}
static inline void atomic16_set(Int128 *ptr, Int128 val)
@@ -141,7 +158,7 @@ static inline void atomic16_set(Int128 *ptr, Int128 val)
do {
cmp = old;
old = atomic16_cmpxchg(ptr, cmp, val);
- } while (old != cmp);
+ } while (int128_ne(old, cmp));
}
# define HAVE_ATOMIC128 1
diff --git a/include/qemu/int128.h b/include/qemu/int128.h
index d2b76ca6ac..f62a46b48c 100644
--- a/include/qemu/int128.h
+++ b/include/qemu/int128.h
@@ -3,7 +3,12 @@
#include "qemu/bswap.h"
-#ifdef CONFIG_INT128
+/*
+ * With TCI, we need to use libffi for interfacing with TCG helpers.
+ * But libffi does not support __int128_t, and therefore cannot pass
+ * or return values of this type, force use of the Int128 struct.
+ */
+#if defined(CONFIG_INT128) && !defined(CONFIG_TCG_INTERPRETER)
typedef __int128_t Int128;
static inline Int128 int128_make64(uint64_t a)
@@ -460,8 +465,7 @@ Int128 int128_divu(Int128, Int128);
Int128 int128_remu(Int128, Int128);
Int128 int128_divs(Int128, Int128);
Int128 int128_rems(Int128, Int128);
-
-#endif /* CONFIG_INT128 */
+#endif /* CONFIG_INT128 && !CONFIG_TCG_INTERPRETER */
static inline void bswap128s(Int128 *s)
{
@@ -472,4 +476,19 @@ static inline void bswap128s(Int128 *s)
#define INT128_MAX int128_make128(UINT64_MAX, INT64_MAX)
#define INT128_MIN int128_make128(0, INT64_MIN)
+/*
+ * When compiler supports a 128-bit type, define a combination of
+ * a possible structure and the native types. Ease parameter passing
+ * via use of the transparent union extension.
+ */
+#ifdef CONFIG_INT128
+typedef union {
+ Int128 s;
+ __int128_t i;
+ __uint128_t u;
+} Int128Alias __attribute__((transparent_union));
+#else
+typedef Int128 Int128Alias;
+#endif /* CONFIG_INT128 */
+
#endif /* INT128_H */
diff --git a/util/int128.c b/util/int128.c
index ed8f25fef1..df6c6331bd 100644
--- a/util/int128.c
+++ b/util/int128.c
@@ -144,4 +144,46 @@ Int128 int128_rems(Int128 a, Int128 b)
return r;
}
+#elif defined(CONFIG_TCG_INTERPRETER)
+
+Int128 int128_divu(Int128 a_s, Int128 b_s)
+{
+ Int128Alias r, a, b;
+
+ a.s = a_s;
+ b.s = b_s;
+ r.u = a.u / b.u;
+ return r.s;
+}
+
+Int128 int128_remu(Int128 a_s, Int128 b_s)
+{
+ Int128Alias r, a, b;
+
+ a.s = a_s;
+ b.s = b_s;
+ r.u = a.u % b.u;
+ return r.s;
+}
+
+Int128 int128_divs(Int128 a_s, Int128 b_s)
+{
+ Int128Alias r, a, b;
+
+ a.s = a_s;
+ b.s = b_s;
+ r.i = a.i / b.i;
+ return r.s;
+}
+
+Int128 int128_rems(Int128 a_s, Int128 b_s)
+{
+ Int128Alias r, a, b;
+
+ a.s = a_s;
+ b.s = b_s;
+ r.i = a.i % b.i;
+ return r.s;
+}
+
#endif
--
2.34.1
