/*!\file sys/swap.h
 * Swapping of short/long values.
 */

#ifndef __SYS_SWAP_BYTES_H
#define __SYS_SWAP_BYTES_H

#ifndef __SYS_W32API_H
#include <sys/w32api.h>
#endif

#ifndef __SYS_CDEFS_H
#include <sys/cdefs.h>
#endif

#ifndef __NETINET_IN_H
#include <netinet/in.h>
#endif

#if defined(__dj_include_netinet_in_h_)
#error "You are using the wrong version of <netinet/in.h>. Ref. point 10 of the INSTALL file"
#endif


__BEGIN_DECLS

#if defined(WIN32) || defined(_WIN32) /* provide some real versions too */
  W32_FUNC unsigned short W32_CALL ntohs (unsigned short);
  W32_FUNC unsigned short W32_CALL htons (unsigned short);
  W32_FUNC unsigned long  W32_CALL ntohl (unsigned long);
  W32_FUNC unsigned long  W32_CALL htonl (unsigned long);
  W32_FUNC unsigned long  cdecl   _w32_intel   (unsigned long x);
  W32_FUNC unsigned short cdecl   _w32_intel16 (unsigned short x);
#endif

#undef  ntohs
#undef  htons
#undef  ntohl
#undef  htonl
#define ntohs(x)  intel16(x)
#define htons(x)  intel16(x)
#define ntohl(x)  intel(x)
#define htonl(x)  intel(x)


/*
 * Hard to believe, but someone uses Watt-32 on a
 * Motorola/PowerPC embedded target.
 */
#if defined(BIG_ENDIAN_MACHINE) || defined(USE_BIGENDIAN)
  #define intel(x)    x
  #define intel16(x)  x

#elif defined(__GNUC__) && !defined(__NO_INLINE__)  /* -O0 */
  #define intel(x)   __ntohl(x)
  #define intel16(x) __ntohs(x)

  /*
   * Ripped (and adapted) from <linux/include/asm-386/byteorder.h>
   */
  /*@unused@*/ _W32_EXTERN_INLINE unsigned long __ntohl (unsigned long x)
  {
    __asm__ __volatile__ (
             "xchgb %b0, %h0\n\t"   /* swap lower bytes  */
             "rorl  $16, %0\n\t"    /* swap words        */
             "xchgb %b0, %h0"       /* swap higher bytes */
            : "=q" (x) : "0" (x));
    return (x);
  }

  /*@unused@*/ _W32_EXTERN_INLINE unsigned short __ntohs (unsigned short x)
  {
    __asm__ __volatile__ (
              "xchgb %b0, %h0"       /* swap bytes */
            : "=q" (x) : "0" (x));
    return (x);
  }

#elif defined(__POCC__)             /* PellesC */
  #define intel(x)   __ntohl(x)
  #define intel16(x) __ntohs(x)

  __declspec(naked) inline unsigned long __fastcall __ntohl (unsigned long x)
  {
    __asm xchg cl, ch    /* 'x' is in ecx */
    __asm ror  ecx, 16
    __asm xchg cl, ch
    __asm mov  eax, ecx
    __asm ret
  }

  __declspec(naked) inline unsigned short __fastcall __ntohs (unsigned short x)
  {
    __asm xchg  cl, ch    /* 'x' is in ecx */
    __asm movzx eax, cx
    __asm ret
  }

#elif (defined(_MSC_VER) && (_MSC_VER >= 1200)) &&  /* MSVC 6+ */ \
      !defined(__POCC__)           /* "pocc -Ze" sets _MSC_VER */
  #define intel(x)   __ntohl(x)
  #define intel16(x) __ntohs(x)

  __declspec(naked) static unsigned long __ntohl (unsigned long x)
  {
    __asm mov  eax, [esp+4]
    __asm xchg al, ah
    __asm ror  eax, 16
    __asm xchg al, ah
    __asm ret
  }

  __declspec(naked) static unsigned short __ntohs (unsigned short x)
  {
    __asm mov  ax, [esp+4]
    __asm xchg al, ah
    __asm ret
  }

#elif defined(__WATCOMC__) && defined(__FLAT__)  /* Watcom 32-bit */
  #define intel(x)   __ntohl(x)
  #define intel16(x) __ntohs(x)

  extern unsigned long __ntohl (unsigned long x);
  #pragma aux  __ntohl =     \
              "xchg al, ah"  \
              "ror  eax, 16" \
              "xchg al, ah"  \
              parm   [eax]   \
              modify [eax];

  extern unsigned short __ntohs (unsigned short x);
  #pragma aux __ntohs =     \
              "xchg al, ah" \
              parm   [ax]   \
              modify [ax];

#elif defined(__WATCOMC__) && !defined(__FLAT__)  /* Watcom 16-bit */
  #define intel(x)   __ntohl(x)
  #define intel16(x) __ntohs(x)

  extern unsigned long __ntohl (unsigned long x);
  #pragma aux  __ntohl =     \
              "xchg al, dh"  \
              "xchg ah, dl"  \
              parm   [dx ax] \
              modify [dx ax];

  extern unsigned short __ntohs (unsigned short x);
  #pragma aux __ntohs =     \
              "xchg al, ah" \
              parm   [ax]   \
              modify [ax];

#elif (defined(__BORLANDC__) && defined(__FLAT__)) || /* bcc32 */ \
      (defined(__DMC__) && (__INTSIZE==4))            /* dmc -mx */
  #include <dos.h>

  #define intel(x)    __ntohl(x)
  #define intel16(x)  __ntohs(x)

  #define __ntohs(x)  (_AX = x, \
                       __emit__(0x86,0xC4),      /* xchg al, ah */ \
                       _AX)

  #define __ntohl(x)  (_EAX = x, \
                       __emit__(0x86,0xC4),      /* xchg al, ah  */ \
                       __emit__(0xC1,0xC8,0x10), /* ror  eax, 16 */ \
                       __emit__(0x86,0xC4),      /* xchg al, ah  */ \
                       _EAX)

#elif defined(__CCDL__) && defined(__386__)      /* LadSoft 386 */
  #define intel(x)    __ntohl(x)
  #define intel16(x)  __ntohs(x)

  static unsigned long __ntohl (unsigned long x)
  {
    asm { mov  eax, [x]
          xchg al, ah
          ror  eax, 16
          xchg al, ah
        }
    return (_EAX);
  }
  static unsigned short __ntohs (unsigned short x)
  {
    asm { mov  ax, [x]
          xchg al, ah
        }
    return (unsigned short)_EAX;  /* doesn't have _AX */
  }

  /* This crashes mysteriously if we use _bswap()
   */
#elif defined(__LCC__) && 0              /* LCC-Win32 */
  #define intel(x)    __ntohl(x)
  #define intel16(x)  __ntohs(x)
  #if 0
    #include <intrinsics.h>
    #define W32_LCC_INTRINSICS_INCLUDED  /* header guard is missing */
    #define __ntohl(x)   (unsigned long) _bswap(x)
    #define __ntohs(x)  ((unsigned short) (_bswap(x) >> 16))
  #else
    unsigned long inline __declspec(naked) __ntohl (unsigned long x)
    {
      _asm ("movl (%esp), %eax");
      _asm ("xchg %ah, %al");
      _asm ("rorl $16, %eax");
      _asm ("xchg %ah, %al");
    }
    unsigned short inline __declspec(naked) __ntohs (unsigned short x)
    {
      _asm ("movs (%esp), %ax");
      _asm ("xchg %ah, %al");
    }
  #endif

#else  /* no inlining possible (or worth the effort) */
  #define intel   W32_NAMESPACE (intel)
  #define intel16 W32_NAMESPACE (intel16)
  #define WATT_NO_INLINE_INTEL

  W32_FUNC unsigned long  cdecl intel   (unsigned long x);
  W32_FUNC unsigned short cdecl intel16 (unsigned short x);
#endif

__END_DECLS

#endif /* __SYS_SWAP_BYTES_H */
