[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [RFC v2 2/5] cputlb: Replace switches in load/store_helper with call
From: |
David Hildenbrand |
Subject: |
Re: [RFC v2 2/5] cputlb: Replace switches in load/store_helper with callback |
Date: |
Thu, 19 Sep 2019 16:53:09 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.8.0 |
On 18.09.19 20:02, Richard Henderson wrote:
> Add a function parameter to perform the actual load/store to ram.
> With optimization, this results in identical code.
>
> Signed-off-by: Richard Henderson <address@hidden>
> ---
> accel/tcg/cputlb.c | 159 +++++++++++++++++++++++----------------------
> 1 file changed, 83 insertions(+), 76 deletions(-)
I would have guessed the compiler propagates the constant and eliminates
the switch completely for the variants. After all, we now have more LOC ...
I would have moved the actual read/write to a separate function
containing the switch statement instead.
But I am pretty sure you know what you're doing here :)
>
> diff --git a/accel/tcg/cputlb.c b/accel/tcg/cputlb.c
> index 2222b87764..b4a63d3928 100644
> --- a/accel/tcg/cputlb.c
> +++ b/accel/tcg/cputlb.c
> @@ -1280,11 +1280,38 @@ static void *atomic_mmu_lookup(CPUArchState *env,
> target_ulong addr,
>
> typedef uint64_t FullLoadHelper(CPUArchState *env, target_ulong addr,
> TCGMemOpIdx oi, uintptr_t retaddr);
> +typedef uint64_t LoadHelper(const void *);
> +
> +/* Wrap the unaligned load helpers to that they have a common signature. */
> +static inline uint64_t wrap_ldub(const void *haddr)
> +{
> + return ldub_p(haddr);
I wonder if you should just add proper type cast to all of the <
uint64_t accessors (e.g., here (uint8_t) ). Shouldn't hurt and makes
people wonder less how the conversion from the int these accessors
return to uint64_t will turn out.
But yeah, you're simply moving code here.
> +}
> +
> +static inline uint64_t wrap_lduw_be(const void *haddr)
> +{
> + return lduw_be_p(haddr);
> +}
> +
> +static inline uint64_t wrap_lduw_le(const void *haddr)
> +{
> + return lduw_le_p(haddr);
> +}
> +
> +static inline uint64_t wrap_ldul_be(const void *haddr)
> +{
> + return (uint32_t)ldl_be_p(haddr);
> +}
> +
> +static inline uint64_t wrap_ldul_le(const void *haddr)
> +{
> + return (uint32_t)ldl_le_p(haddr);
> +}
Looks sane to me!
--
Thanks,
David / dhildenb
- [Qemu-devel] [RFC v2 0/5] Move notdirty handling to cputlb, Richard Henderson, 2019/09/18
- [Qemu-devel] [RFC v2 1/5] cputlb: Disable __always_inline__ without optimization, Richard Henderson, 2019/09/18
- [Qemu-devel] [RFC v2 2/5] cputlb: Replace switches in load/store_helper with callback, Richard Henderson, 2019/09/18
- Re: [RFC v2 2/5] cputlb: Replace switches in load/store_helper with callback,
David Hildenbrand <=
- [Qemu-devel] [RFC v2 4/5] exec: Adjust notdirty tracing, Richard Henderson, 2019/09/18
- [Qemu-devel] [RFC v2 5/5] cputlb: Move NOTDIRTY handling from I/O path to TLB path, Richard Henderson, 2019/09/18
- [Qemu-devel] [RFC v2 3/5] cputlb: Introduce TLB_BSWAP, Richard Henderson, 2019/09/18
- Re: [Qemu-devel] [RFC v2 0/5] Move notdirty handling to cputlb, no-reply, 2019/09/19
- Re: [Qemu-devel] [RFC v2 0/5] Move notdirty handling to cputlb, no-reply, 2019/09/19
- Re: [Qemu-devel] [RFC v2 0/5] Move notdirty handling to cputlb, no-reply, 2019/09/19