Re: [PATCH v4 08/10] qemu/bswap: Add const_le64()

[Fan Ni]

On Mon, Feb 06, 2023 at 05:28:14PM +0000, Jonathan Cameron wrote:
> From: Ira Weiny <ira.weiny@intel.com>
> 
> Gcc requires constant versions of cpu_to_le* calls.
> 
> Add a 64 bit version.
> 
> Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
> Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> Reviewed-by: Gregory Price <gregory.price@memverge.com>
> Tested-by: Gregory Price <gregory.price@memverge.com>
> Signed-off-by: Ira Weiny <ira.weiny@intel.com>
> Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
> 

Reviewed-by: Fan Ni <fan.ni@samsung.com>

> ---
> v2: Update comment (Philippe)
> ---
>  include/qemu/bswap.h | 12 +++++++++++-
>  1 file changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/include/qemu/bswap.h b/include/qemu/bswap.h
> index 3cbe52246b..eb3bcf2520 100644
> --- a/include/qemu/bswap.h
> +++ b/include/qemu/bswap.h
> @@ -129,11 +129,20 @@ CPU_CONVERT(le, 32, uint32_t)
>  CPU_CONVERT(le, 64, uint64_t)
>  
>  /*
> - * Same as cpu_to_le{16,32}, except that gcc will figure the result is
> + * Same as cpu_to_le{16,32,64}, 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 HOST_BIG_ENDIAN
> +# 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) |              \
> @@ -143,6 +152,7 @@ CPU_CONVERT(le, 64, uint64_t)
>      ((((_x) & 0x00ff) << 8) |                    \
>       (((_x) & 0xff00) >> 8))
>  #else
> +# define const_le64(_x) (_x)
>  # define const_le32(_x) (_x)
>  # define const_le16(_x) (_x)
>  #endif
> -- 
> 2.37.2
> 
>