* Nikolay Borisov:
> +/*
> + * Compare A and B bytewise in the byte order of the machine.
> + * A and B are known to be different. This is needed only on little-endian
> + * machines.
> + */
> +static inline int memcmp_bytes(unsigned long a, unsigned long b)
> +{
> + long srcp1 = (long) &a;
> + long srcp2 = (long) &b;
> + unsigned long a0, b0;
> +
> + do {
> + a0 = ((uint8_t *) srcp1)[0];
> + b0 = ((uint8_t *) srcp2)[0];
> + srcp1 += 1;
> + srcp2 += 1;
> + } while (a0 == b0);
> + return a0 - b0;
> +}
Should this be this?
static inline int memcmp_bytes(unsigned long a, unsigned long b)
{
if (sizeof(a) == 4)
return __builtin_bswap32(a) < __builtin_bswap32(b) ? -1 : 0;
else
return __builtin_bswap64(a) < __builtin_bswap64(b) ? -1 : 0;
}
(Or whatever macro versions the kernel has for this.)
Or is the expectation that targets that don't have an assembler
implementation for memcmp have also bad bswap built-ins?
Thanks,
Florian
