------- Comment #4 from rguenth at gcc dot gnu dot org 2009-04-18 10:22 -------
typedef unsigned char u8;
struct __large_struct { unsigned long buf[100]; };
static inline __attribute__((always_inline)) unsigned long
__copy_from_user_inatomic(void *to, const void *from, unsigned long n)
{
unsigned long ret = 0;
asm volatile("1: mov""b"" %2,%""b""1\n" "2:\n"
".section .fixup,\"ax\"\n"
"3: mov %3,%0\n"
" xor""b"" %""b""1,%""b""1\n"
" jmp 2b\n"
".previous\n"
" .section __ex_table,\"a\"\n"
" " ".balign 4" " " "\n"
" " ".long" " " "1b" "," "3b" "\n"
" .previous\n"
: "=r" (ret), "=q"(*(u8 *)to)
: "m" ((*(struct __large_struct *)(from))), "i" (1), "0" (ret));
return ret;
}
int romchecksum(const unsigned char *rom, unsigned char c)
{
unsigned char sum;
for (sum = 0;
!__copy_from_user_inatomic(&(c), ( typeof(c) *)(rom++), sizeof(c));)
sum += c;
}
Likely some missed corner-case in walking address-taken operations in asms.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=39804
