Quoting Pavel Roskin <[EMAIL PROTECTED]>:
366976 original
364988 "=q", xchgb
365460 "=q", rolw $8,%w0
365420 "=r", rolw $8,%w0
364996 monstrosity ("=r", conditional xchgb/rolw)
364728 "little details"
Marginally better (by just 12 bytes):
364716 "little details" + "monstrosity"
#define grub_swap_lo(x) \
({ \
grub_uint32_t _x = (x), _y; \
asm ( \
".ifc %0,%%eax\n" \
"xchgb %b0,%h0\n" \
".else\n" \
".ifc %0,%%ebx\n" \
"xchgb %b0,%h0\n" \
".else\n" \
".ifc %0,%%ecx\n" \
"xchgb %b0,%h0\n" \
".else\n" \
".ifc %0,%%edx\n" \
"xchgb %b0,%h0\n" \
".else\n" \
"rolw $8,%w0\n" \
".endif\n" \
".endif\n" \
".endif\n" \
".endif\n" \
: "=r"(_y) : "0"(_x) \
); \
_y; \
})
#define grub_swap_hi(x) \
({ \
grub_uint32_t _x = (x), _y; \
asm ( \
"roll $0x10,%0\n" \
: "=r"(_y) : "0"(_x) \
); \
_y; \
})
#define grub_swap_bytes32(x) grub_swap_lo(grub_swap_hi(grub_swap_lo(x)))
--
Regards,
Pavel Roskin
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