Re: [PATCH mini-os enhancements for vtpm 3/8] add endian support to mini-os

[Samuel Thibault <samuel.thibault@ens-lyon.org>]

Matthew Fioravante, le Mon 17 Sep 2012 17:57:11 -0400, a écrit :
> diff --git a/extras/mini-os/include/byteorder.h
> b/extras/mini-os/include/byteorder.h
> --- /dev/null
> +++ b/extras/mini-os/include/byteorder.h

Ok.

> -static inline uint16_t bswap_16(uint16_t x)
> -{
> -    return
> -    ((((x) & 0xff00) >> 8) | (((x) & 0xff) << 8));
> -}
> -
> +#define bswap_16(x) ((uint16_t)(                         \
> +             (((uint16_t)(x) & (uint16_t)0x00ffU) << 8)
> |                  \
> +             (((uint16_t)(x) & (uint16_t)0xff00U) >> 8)))

Why replacing the inline with a macro?  AIUI, inlines provide the same
efficiency while providing some minimal type checking (and safety
against things like bswap_16(x++).

> diff --git a/extras/mini-os/include/endian.h
> diff --git a/extras/mini-os/include/ia64/arch_endian.h
> diff --git a/extras/mini-os/include/ia64/arch_wordsize.h
> diff --git a/extras/mini-os/include/x86/arch_endian.h
> diff --git a/extras/mini-os/include/x86/x86_32/arch_wordsize.h
> diff --git a/extras/mini-os/include/x86/x86_64/arch_wordsize.h

Ok.

Samuel