com32/include/byteswap.h

   1 #ifndef _BYTESWAP_H
   2 #define _BYTESWAP_H
   3
   4 /* COM32 will be running on an i386 platform */
   5
   6 #include <stdint.h>
   7 #include <klibc/compiler.h>
   8
   9 #define __bswap_16_macro(v) ((uint16_t)                                 \
  10                              (((uint16_t)(v) << 8) |                    \
  11                               ((uint16_t)(v) >> 8)))
  12
  13 static inline __constfunc uint16_t __bswap_16(uint16_t v)
  14 {
  15     return __bswap_16_macro(v);
  16 }
  17
  18 #define bswap_16(x) (__builtin_constant_p(x) ?                          \
  19                         __bswap_16_macro(x) : __bswap_16(x))
  20
  21 #define __bswap_32_macro(v) ((uint32_t)                                 \
  22                              ((((uint32_t)(v) & 0x000000ff) << 24) |    \
  23                               (((uint32_t)(v) & 0x0000ff00) << 8)  |    \
  24                              (((uint32_t)(v) & 0x00ff0000) >> 8)  |     \
  25                               (((uint32_t)(v) & 0xff000000) >> 24)))
  26
  27 static inline __constfunc uint32_t __bswap_32(uint32_t v)
  28 {
  29 #if __SIZEOF_POINTER__ == 4
  30     asm("xchgb %h0,%b0 ; roll $16,%0 ; xchgb %h0,%b0"
  31         : "+q" (v));
  32 #elif __SIZEOF_POINTER__ == 8
  33     asm("bswap  %0"
  34         : "=r" (v)
  35         : "0" (v));
  36 #else
  37 #error "unable to build for architecture"
  38 #endif
  39     return v;
  40 }
  41
  42 #define bswap_32(x) (__builtin_constant_p(x) ?                          \
  43                          __bswap_32_macro(x) : __bswap_32(x))
  44
  45
  46 #define __bswap_64_macro(v) ((uint64_t)                                 \
  47     (((uint64_t)__bswap_32_macro((uint32_t)(v)) << 32) |                \
  48      (__bswap_32_macro((uint32_t)((uint64_t)(v) >> 32)))))
  49
  50 static inline __constfunc uint64_t __bswap_64(uint64_t v)
  51 {
  52     return ((uint64_t)__bswap_32(v) << 32) | __bswap_32(v >> 32);
  53 }
  54
  55 #define bswap_64(x) (__builtin_constant_p(x) ?                          \
  56                         __bswap_64_macro(x) :  __bswap_64(x))
  57
  58 #endif /* byteswap.h */