On Wed, 3 May 2023 at 08:11, Richard Henderson
<[email protected]> wrote:
>
> Signed-off-by: Richard Henderson <[email protected]>
> ---
> accel/tcg/cputlb.c | 103 +++----
> accel/tcg/user-exec.c | 12 +-
> accel/tcg/ldst_atomicity.c.inc | 491 +++++++++++++++++++++++++++++++++
> 3 files changed, 540 insertions(+), 66 deletions(-)
> +/**
> + * store_atom_insert_al16:
> + * @p: host address
> + * @val: shifted value to store
> + * @msk: mask for value to store
> + *
> + * Atomically store @val to @p masked by @msk.
> + */
> +static void store_atom_insert_al16(Int128 *ps, Int128Alias val, Int128Alias
> msk)
> +{
> +#if defined(CONFIG_ATOMIC128)
> + __uint128_t *pu, old, new;
> +
> + /* With CONFIG_ATOMIC128, we can avoid the memory barriers. */
> + pu = __builtin_assume_aligned(ps, 16);
> + old = *pu;
> + do {
> + new = (old & ~msk.u) | val.u;
> + } while (!__atomic_compare_exchange_n(pu, &old, new, true,
> + __ATOMIC_RELAXED,
> __ATOMIC_RELAXED));
> +#elif defined(CONFIG_CMPXCHG128)
> + __uint128_t *pu, old, new;
> +
> + /*
> + * Without CONFIG_ATOMIC128, __atomic_compare_exchange_n will always
> + * defer to libatomic, so we must use __sync_val_compare_and_swap_16
> + * and accept the sequential consistency that comes with it.
> + */
> + pu = __builtin_assume_aligned(ps, 16);
> + do {
> + old = *pu;
> + new = (old & ~msk.u) | val.u;
> + } while (!__sync_bool_compare_and_swap_16(pu, old, new));
Comment says "__sync_val..." but code says "__sync_bool...". Which is right?
> +#else
> + qemu_build_not_reached();
> +#endif
> +}
-- PMM
