On Wed, 2007-08-15 at 16:30 -0500, Timur Tabi wrote: > This patch adds the setmaskedbits_xxx() macros, which are used to set a > multiple-bit bit pattern in a register. The macros include a mask, which > zeros the respective bits before applying the value via a bitwise-OR. > There are big-endian and little-endian versions for 8, 16, 32, and 64 bits. > > These new macros are useful because the setbits macros can only be used > to set single-bit fields. For example, if you have a 32-bit register > where bits 17-20 need to be set to 0100, you would do > setmaskedbits_be32(p, 4 << 11, 0xF << 11). > > Signed-off-by: Timur Tabi <[EMAIL PROTECTED]> > --- > > Updated the changelog to include a reason why you'd want these macros. > I have a number of new SOC device drivers coming up that will use these > macros, if this patch is accepted. > > include/asm-powerpc/io.h | 13 +++++++++++++ > 1 files changed, 13 insertions(+), 0 deletions(-) > > diff --git a/include/asm-powerpc/io.h b/include/asm-powerpc/io.h > index bb8d965..ac3defb 100644 > --- a/include/asm-powerpc/io.h > +++ b/include/asm-powerpc/io.h > @@ -734,6 +734,19 @@ static inline void * bus_to_virt(unsigned long address) > #define setbits16(_addr, _v) out_be16((_addr), in_be16(_addr) | (_v)) > #define clrbits16(_addr, _v) out_be16((_addr), in_be16(_addr) & ~(_v)) > > +#ifdef __powerpc64__ > +#define setmaskedbits_be64(a, v, m) out_be64((a), (in_be64(a) & ~(m)) | (v)) > +#define setmaskedbits_le64(a, v, m) out_le64((a), (in_le64(a) & ~(m)) | (v)) > +#endif > + > +#define setmaskedbits_be32(a, v, m) out_be32((a), (in_be32(a) & ~(m)) | (v)) > +#define setmaskedbits_be16(a, v, m) out_be16((a), (in_be16(a) & ~(m)) | (v)) > + > +#define setmaskedbits_le32(a, v, m) out_le32((a), (in_le32(a) & ~(m)) | (v)) > +#define setmaskedbits_le16(a, v, m) out_le16((a), (in_le16(a) & ~(m)) | (v)) > + > +#define setmaskedbits_8(a, v, m) out_8((a), (in_8(a) & ~(m)) | (v))
Can you extract the masking logic, rather than repeating it 7 times: #define maskbits(a, v, m) ((a) & ~(m) | (v)) And if you're going to the trouble of making a macro, why not make it a bit more useful and have it check that the value and the mask match, ie: (v & ~m == 0) Final random thought, you could make the size/endian an argument: #define setmaskedbits(a, v, m, s) out_##s((a), (in_##s(a) & ~(m) | (v)) cheers -- Michael Ellerman OzLabs, IBM Australia Development Lab wwweb: http://michael.ellerman.id.au phone: +61 2 6212 1183 (tie line 70 21183) We do not inherit the earth from our ancestors, we borrow it from our children. - S.M.A.R.T Person
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