Re: Endianness macros capitalization

[Pavel Roskin]

Quoting Pavel Roskin <address@hidden>:

> 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