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@gmx.de
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