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Re: [PATCH 3/4] qemu/bswap: Add const_le64() and const_be64()
From: |
Richard Henderson |
Subject: |
Re: [PATCH 3/4] qemu/bswap: Add const_le64() and const_be64() |
Date: |
Thu, 17 Sep 2020 14:19:20 -0700 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 |
On 9/17/20 9:31 AM, Philippe Mathieu-Daudé wrote:
> From: Philippe Mathieu-Daudé <f4bug@amsat.org>
>
> We already have the const_endian() macros for 16-bit and
> 32-bit values. Implement the 64-bit equivalent macros.
>
> Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
> ---
> include/qemu/bswap.h | 22 +++++++++++++++++++++-
> 1 file changed, 21 insertions(+), 1 deletion(-)
>
> diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
> index 6885984e00c..de256cea3ab 100644
> --- a/include/qemu/bswap.h
> +++ b/include/qemu/bswap.h
> @@ -83,11 +83,20 @@ static inline void bswap64s(uint64_t *s)
> #endif
>
> /*
> - * Same as cpu_to_{be,le}{16,32} described below, except that gcc will
> + * Same as cpu_to_{be,le}{16,32,64} described below, except that gcc will
> * figure the result is a compile-time constant if you pass in a constant.
> * So this can be used to initialize static variables.
> */
> #if defined(HOST_WORDS_BIGENDIAN)
> +# define const_le64(_x) \
> + ((((_x) & 0x00000000000000ffU) << 56) | \
> + (((_x) & 0x000000000000ff00U) << 40) | \
> + (((_x) & 0x0000000000ff0000U) << 24) | \
> + (((_x) & 0x00000000ff000000U) << 8) | \
> + (((_x) & 0x000000ff00000000U) >> 8) | \
> + (((_x) & 0x0000ff0000000000U) >> 24) | \
> + (((_x) & 0x00ff000000000000U) >> 40) | \
> + (((_x) & 0xff00000000000000U) >> 56))
> # define const_le32(_x) \
> ((((_x) & 0x000000ffU) << 24) | \
> (((_x) & 0x0000ff00U) << 8) | \
> @@ -96,11 +105,22 @@ static inline void bswap64s(uint64_t *s)
> # define const_le16(_x) \
> ((((_x) & 0x00ff) << 8) | \
> (((_x) & 0xff00) >> 8))
> +# define const_be64(_x) (_x)
> # define const_be32(_x) (_x)
> # define const_be16(_x) (_x)
> #else
> +# define const_le64(_x) (_x)
> # define const_le32(_x) (_x)
> # define const_le16(_x) (_x)
> +# define const_be64(_x) \
> + ((((_x) & 0x00000000000000ffU) << 56) | \
> + (((_x) & 0x000000000000ff00U) << 40) | \
> + (((_x) & 0x0000000000ff0000U) << 24) | \
> + (((_x) & 0x00000000ff000000U) << 8) | \
> + (((_x) & 0x000000ff00000000U) >> 8) | \
> + (((_x) & 0x0000ff0000000000U) >> 24) | \
> + (((_x) & 0x00ff000000000000U) >> 40) | \
> + (((_x) & 0xff00000000000000U) >> 56))
> # define const_be32(_x) \
> ((((_x) & 0x000000ffU) << 24) | \
> (((_x) & 0x0000ff00U) << 8) | \
>
This duplication suggests that we define these as const_bswap64, and define
const_le64/be64 on top of that. Similar for the other defines as you're moving
them.
r~