On Thu, 13 Aug 2009, Nicolas Pitre wrote:
>
> In addition to X86, PowerPC and S390 are capable of unaligned memory
> accesses.
>
> Signed-off-by: Nicolas Pitre <nico@xxxxxxx>
Ack on all your patches (1-3 + this). Looks fine to me.
I do wonder if we should try to do basically "per-architecture hack
header-files", and then have for each architecture a small trivial
'hack-x86.h' kind of thing that just does
/* x86 hacks */
#define get_be32(p) ntohl(*(unsigned int *)(p))
#define put_be32(p, v) do { *(unsigned int *)(p) = htonl(v); } while (0)
#define setW(x, val) (*(volatile unsigned int *)&W(x) = (val))
#define SHA_ASM(op, x, n) ({ unsigned int __res; __asm__(op " %1,%0":"=r" (__res):"i" (n), "0" (x)); __res; })
#define SHA_ROL(x,n) SHA_ASM("rol", x, n)
#define SHA_ROR(x,n) SHA_ASM("ror", x, n)
and then we'd have each architecture separated out. Add a few
"generic helpers":
- be32-generic.h:
#define get_be32(p) ( \
(*((unsigned char *)(p) + 0) << 24) | \
(*((unsigned char *)(p) + 1) << 16) | \
(*((unsigned char *)(p) + 2) << 8) | \
(*((unsigned char *)(p) + 3) << 0) )
#define put_be32(p, v) do { \
unsigned int __v = (v); \
*((unsigned char *)(p) + 0) = __v >> 24; \
*((unsigned char *)(p) + 1) = __v >> 16; \
*((unsigned char *)(p) + 2) = __v >> 8; \
*((unsigned char *)(p) + 3) = __v >> 0; } while (0)
- rotate-generic.h:
#define SHA_ROT(X,l,r) (((X) << (l)) | ((X) >> (r)))
#define SHA_ROL(X,n) SHA_ROT(X,n,32-(n))
#define SHA_ROR(X,n) SHA_ROT(X,32-(n),n)
that architectures could use when they want to use some particular
portable version. Then, add a final "hack-generic.h" with the fallback
cases that just does
#include "be32-generic.h"
#include "rotate-generic.h"
#define setW(x,val) (W(x) = (val))
and you'd have all the hacks separated out and fairly easily used by
different architectures.. (ie the ARM version would just look like
- hack-arm.h:
#include "be32-generic.h"
#include "rotate-generic.h"
#define setW(x, val) do { W(x) = (val); __asm__("":::"memory"); } while (0)
and you'd be all done.
Hmm? I don't know if this kind of generalization is strictly needed, so
I'm just throwing it out as an idea.
Linus
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