[virtio] [PATCH] introduction: add note on bitfield portability

[virtio] [PATCH] introduction: add note on bitfield portability

[Michael S. Tsirkin]

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 introduction.tex | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/introduction.tex b/introduction.tex
index d0b770e..18ad76e 100644
--- a/introduction.tex
+++ b/introduction.tex
@@ -175,5 +175,12 @@ packed by C compilers on little-endian architectures but not the
 way bitfields are packed by C compilers on big-endian
 architectures.
 
+Assuming that CPU_TO_BE16 converts a 16-bit integer from a native
+CPU to the big-endian byte order, the following is the equivalent
+portable C code to generate a value in this format:
+\begin{lstlisting}
+CPU_TO_BE16(B << 15 | A)
+\end{lstlisting}
+
 \newpage
 
-- 
MST

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Re: [virtio] [PATCH] introduction: add note on bitfield portability

[Cornelia Huck]

On Tue, 6 Mar 2018 16:35:46 +0200
"Michael S. Tsirkin" <mst@redhat.com> wrote:

[You picked my old email address :)]

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  introduction.tex | 7 +++++++
>  1 file changed, 7 insertions(+)
> 
> diff --git a/introduction.tex b/introduction.tex
> index d0b770e..18ad76e 100644
> --- a/introduction.tex
> +++ b/introduction.tex
> @@ -175,5 +175,12 @@ packed by C compilers on little-endian architectures but not the
>  way bitfields are packed by C compilers on big-endian
>  architectures.
>  
> +Assuming that CPU_TO_BE16 converts a 16-bit integer from a native
> +CPU to the big-endian byte order, the following is the equivalent
> +portable C code to generate a value in this format:
> +\begin{lstlisting}
> +CPU_TO_BE16(B << 15 | A)
> +\end{lstlisting}
> +
>  \newpage
>  

Reviewed-by: Cornelia Huck <cohuck@redhat.com>

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