----- Original Message -----
> On 04/25/2016 03:48 PM, Sam Ravnborg wrote:
> > Hi Dave.
> >
> >> Sparc64 requires type-aligned memory access. Since data buffers may not
> >> be properly aligned, implement a safe copy from memory per data type.
> >>
> >> Signed-off-by: Dave Kleikamp <[email protected]>
> >> ---
> >> defs.h | 41 +++++++++++++++++++++++++++++++++++++++++
> >> 1 files changed, 41 insertions(+), 0 deletions(-)
> >>
> >> diff --git a/defs.h b/defs.h
> >> index e3afc58..d9d4559 100644
> >> --- a/defs.h
> >> +++ b/defs.h
> >> @@ -2187,6 +2187,45 @@ struct builtin_debug_table {
> >> * Facilitators for pulling correctly-sized data out of a buffer at a
> >> * known address.
> >> */
> >> +
> >> +#ifdef NEED_ALIGNED_MEM_ACCESS
> >> +
> >> +#define DEF_LOADER(TYPE) \
> >> +static inline TYPE \
> >> +load_##TYPE (char *addr) \
> >> +{ \
> >> + TYPE ret; \
> >> + size_t i = sizeof(TYPE); \
> >> + while (i--) \
> >> + ((char *)&ret)[i] = addr[i]; \
> >> + return ret; \
> >> +}
> >> +
> >> +DEF_LOADER(int);
> >> +DEF_LOADER(uint);
> >> +DEF_LOADER(long);
> >> +DEF_LOADER(ulong);
> >> +DEF_LOADER(ulonglong);
> >> +DEF_LOADER(ushort);
> >> +DEF_LOADER(short);
> >> +typedef void *pointer_t;
> >> +DEF_LOADER(pointer_t);
> >> +
> >> +#define LOADER(TYPE) load_##TYPE
> > A simpler model would be
> > #define LOADER(TYPE, addr) \
> > ({ \
> > TYPE ret; \
> > memcpy(&ret, (void *)addr, sizeof(TYPE)); \
> > ret; \
> > })
>
> This does simplify things a bit.
>
> >
> > I would expect the compiler to optimize this away for archs
> > that do not require aligned access.
>
> I hesitate to to replace the macros for every architecture with this.
> I'll let Dave A. make that call, but I think it can improve the
> NEED_ALIGNED_MEM_ACCESS case.
Do not modify the macros for the existing architectures.
Thanks,
Dave
>
> >
> > Quick test:
> >
> > #include <string.h>
> > #include <stdio.h>
> >
> > #define LOADER(TYPE, addr) \
> > ({ \
> > TYPE ret; \
> > memcpy(&ret, (void*)addr, sizeof(TYPE)); \
> > ret; \
> > })
> >
> > #define INT(ADDR) LOADER(int, ADDR)
> >
> > void main(void)
> > {
> > int i = 37;
> > int j = -17;
> >
> > printf("i=%d j=%d\n", INT(&i), INT(&j));
> > }
> >
> >
> > Sam
> >
>
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>
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