On Wed, 10 May 2023 18:29:32 +0200,
Oswald Buddenhagen wrote:
>
> The idea to encode the bitfield manipulation in the register address is
> quite clever, but doing that by hand is ugly and error-prone. So derive
> it automatically from the mask instead.
>
> Macros cannot #define other macros, so we now declare enums instead.
>
> This also adds macros for decoding the register definitions. These will
> be used by later commits.
>
> Signed-off-by: Oswald Buddenhagen <oswald.buddenhagen@xxxxxx>
> ---
> include/sound/emu10k1.h | 113 ++++++++++++++++++----------------------
> 1 file changed, 50 insertions(+), 63 deletions(-)
>
> diff --git a/include/sound/emu10k1.h b/include/sound/emu10k1.h
> index 8fe80dcee71b..f4e05a2897e8 100644
> --- a/include/sound/emu10k1.h
> +++ b/include/sound/emu10k1.h
> @@ -38,6 +38,22 @@
>
> #define IP_TO_CP(ip) ((ip == 0) ? 0 : (((0x00001000uL | (ip & 0x00000FFFL)) << (((ip >> 12) & 0x000FL) + 4)) & 0xFFFF0000uL))
>
> +#define SUB_REG_NC(reg, field, mask) \
> + enum { \
> + field ## _MASK = mask, \
> + field = reg | \
> + (__builtin_ctz(mask) << 16) | \
> + (__builtin_popcount(mask) << 24), \
> + };
> +#define SUB_REG(reg, field, mask) SUB_REG_NC(reg, reg ## _ ## field, mask)
This macro needs some more comments. It's a good opportunity to
explain what's the real raw register and what's the sub(?) register,
and which one is used for which helper, etc.
thanks,
Takashi
