diff options
Diffstat (limited to 'libc/sysdeps/linux/i386/bits/byteswap.h')
| -rw-r--r-- | libc/sysdeps/linux/i386/bits/byteswap.h | 86 |
1 files changed, 52 insertions, 34 deletions
diff --git a/libc/sysdeps/linux/i386/bits/byteswap.h b/libc/sysdeps/linux/i386/bits/byteswap.h index d08a342ab..33af20888 100644 --- a/libc/sysdeps/linux/i386/bits/byteswap.h +++ b/libc/sysdeps/linux/i386/bits/byteswap.h @@ -1,5 +1,5 @@ /* Macros to swap the order of bytes in integer values. - Copyright (C) 1997, 1998, 2000, 2002 Free Software Foundation, Inc. + Copyright (C) 1997, 1998, 2000, 2002, 2003 Free Software Foundation, Inc. This file is part of the GNU C Library. The GNU C Library is free software; you can redistribute it and/or @@ -28,60 +28,78 @@ #define __bswap_constant_16(x) \ ((((x) >> 8) & 0xff) | (((x) & 0xff) << 8)) -#if defined __GNUC__ && __GNUC__ >= 2 -# define __bswap_16(x) \ +#ifdef __GNUC__ +# if __GNUC__ >= 2 +# define __bswap_16(x) \ (__extension__ \ - ({ register unsigned short int __v; \ - if (__builtin_constant_p (x)) \ - __v = __bswap_constant_16 (x); \ + ({ register unsigned short int __v, __x = (x); \ + if (__builtin_constant_p (__x)) \ + __v = __bswap_constant_16 (__x); \ else \ - __asm__ __volatile__ ("rorw $8, %w0" \ - : "=r" (__v) \ - : "0" ((unsigned short int) (x)) \ - : "cc"); \ + __asm__ ("rorw $8, %w0" \ + : "=r" (__v) \ + : "0" (__x) \ + : "cc"); \ __v; })) -#else +# else /* This is better than nothing. */ -# define __bswap_16(x) __bswap_constant_16 (x) +# define __bswap_16(x) \ + (__extension__ \ + ({ register unsigned short int __x = (x); __bswap_constant_16 (__x); })) +# endif +#else +static __inline unsigned short int +__bswap_16 (unsigned short int __bsx) +{ + return __bswap_constant_16 (__bsx); +} #endif - /* Swap bytes in 32 bit value. */ #define __bswap_constant_32(x) \ ((((x) & 0xff000000) >> 24) | (((x) & 0x00ff0000) >> 8) | \ (((x) & 0x0000ff00) << 8) | (((x) & 0x000000ff) << 24)) -#if defined __GNUC__ && __GNUC__ >= 2 +#ifdef __GNUC__ +# if __GNUC__ >= 2 /* To swap the bytes in a word the i486 processors and up provide the `bswap' opcode. On i386 we have to use three instructions. */ -# if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ -# define __bswap_32(x) \ +# if !defined __i486__ && !defined __pentium__ && !defined __pentiumpro__ \ + && !defined __pentium4__ +# define __bswap_32(x) \ (__extension__ \ - ({ register unsigned int __v; \ - if (__builtin_constant_p (x)) \ - __v = __bswap_constant_32 (x); \ + ({ register unsigned int __v, __x = (x); \ + if (__builtin_constant_p (__x)) \ + __v = __bswap_constant_32 (__x); \ else \ - __asm__ __volatile__ ("rorw $8, %w0;" \ - "rorl $16, %0;" \ - "rorw $8, %w0" \ - : "=r" (__v) \ - : "0" ((unsigned int) (x)) \ - : "cc"); \ + __asm__ ("rorw $8, %w0;" \ + "rorl $16, %0;" \ + "rorw $8, %w0" \ + : "=r" (__v) \ + : "0" (__x) \ + : "cc"); \ __v; })) -# else -# define __bswap_32(x) \ +# else +# define __bswap_32(x) \ (__extension__ \ - ({ register unsigned int __v; \ - if (__builtin_constant_p (x)) \ - __v = __bswap_constant_32 (x); \ + ({ register unsigned int __v, __x = (x); \ + if (__builtin_constant_p (__x)) \ + __v = __bswap_constant_32 (__x); \ else \ - __asm__ __volatile__ ("bswap %0" \ - : "=r" (__v) \ - : "0" ((unsigned int) (x))); \ + __asm__ ("bswap %0" : "=r" (__v) : "0" (__x)); \ __v; })) +# endif +# else +# define __bswap_32(x) \ + (__extension__ \ + ({ register unsigned int __x = (x); __bswap_constant_32 (__x); })) # endif #else -# define __bswap_32(x) __bswap_constant_32 (x) +static __inline unsigned int +__bswap_32 (unsigned int __bsx) +{ + return __bswap_constant_32 (__bsx); +} #endif |