On Fri, May 30, 2014 at 1:21 PM, H. Peter Anvin <hpa@xxxxxxxxx> wrote: > On 05/30/2014 01:09 PM, Andy Lutomirski wrote: >>> >>> I came up with the following, it seems like a reasonable simplification: >>> >>>> #define _LE(x, bits, ifnot) \ >>>> __builtin_choose_expr( \ >>>> (sizeof(x) == bits/8), \ >>>> (__typeof__(x))le##bits##toh(x), ifnot) >> >> This will do awful things if x is a floating-point type, and, for >> integers, the cast is probably unnecessary. But it should be okay. >> > > I mostly wanted to preserve the signedness. Yes, if we care about > floating-point it gets trickier. > > At some point hopefully there will be a native C feature to handle this > crap. > >>>> extern void bad_le(uint64_t); >> >> If this ever goes in a common header, then we should do the >> __attribute__((error)) thing. I wonder if it would ever make sense to >> have __LINUX_HOSTPROG__ and make some of the basic headers work. Hmm. >> >>>> #define _LAST_LE(x) \ >>>> __builtin_choose_expr(sizeof(x) == 1, (x), bad_le(x)) >>>> >>>> #define LE(x) \ >>>> _LE(x, 64, _LE(x, 32, _LE(x, 16, _LAST_LE(x)))) >>> >>> What do you think? >> >> My only real real objection is that _LE sounds like converting *to* >> little-endian to me. Admittedly, that's the same thing on any >> remotely sane architecture, but still. > > GET_LE() then? Sounds good. Are you planning on writing the patch? I think my v2 is good -- the only diff I could find in my image.c files and Stephen's was in the alt_xyz output, and I think I fixed that in v2. --Andy -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
