/*	Public domain	*/

#ifndef _LIBPERCGI_BYTESWAP_H_
#define _LIBPERCGI_BYTESWAP_H_

#include <percgi/config/have_64bit.h>
#include <percgi/config/have_long_double.h>
#include <percgi/config/_mk_big_endian.h>
#include <percgi/config/_mk_little_endian.h>

__BEGIN_DECLS
/*
 * Swap 16-bit
 */
#if defined(__GNUC__) && defined(__i386__) && \
   !(__GNUC__ == 2 && __GNUC_MINOR__ == 95)
static __inline__ Uint16
CGI_Swap16(Uint16 x)
{
	__asm__("xchgb %b0,%h0" :
	        "=q" (x) :
		"0" (x));
	return (x);
}
#elif defined(__GNUC__) && defined(__x86_64__)
static __inline__ Uint16
CGI_Swap16(Uint16 x)
{
	__asm__("xchgb %b0,%h0" :
	        "=Q" (x) :
		"0" (x));
	return (x);
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
static __inline__ Uint16
CGI_Swap16(Uint16 x)
{
	Uint16 rv;
	__asm__("rlwimi %0,%2,8,16,23" :
	        "=&r" (rv) :
		"0" (x >> 8), "r" (x));
	return (rv);
}
#else
static __inline__ Uint16
CGI_Swap16(Uint16 x)
{
	return ((x<<8)|(x>>8));
}
#endif

/*
 * Swap 32-bit
 */
#if defined(__GNUC__) && defined(__i386__)
static __inline__ Uint32
CGI_Swap32(Uint32 x)
{
	__asm__("bswap %0" :
	        "=r" (x) :
		"0" (x));
	return (x);
}
#elif defined(__GNUC__) && defined(__x86_64__)
static __inline__ Uint32
CGI_Swap32(Uint32 x)
{
	__asm__("bswapl %0" :
	        "=r" (x) :
		"0" (x));
	return (x);
}
#elif defined(__GNUC__) && (defined(__powerpc__) || defined(__ppc__))
static __inline__ Uint32
CGI_Swap32(Uint32 x)
{
	Uint32 rv;
	__asm__("rlwimi %0,%2,24,16,23" :
	        "=&r" (rv) :
		"0" (x>>24), "r" (x));
	__asm__("rlwimi %0,%2,8,8,15" :
	        "=&r" (rv) :
		"0" (rv), "r" (x));
	__asm__("rlwimi %0,%2,24,0,7" :
	        "=&r" (rv) :
		"0" (rv), "r" (x));
	return (rv);
}
#else
static __inline__ Uint32
CGI_Swap32(Uint32 x)
{
	return ((x << 24) |
	       ((x << 8) & 0x00FF0000) | ((x >> 8) & 0x0000FF00) | 
	        (x >> 24));
}
#endif

/*
 * Swap 64-bit
 */
#ifdef HAVE_64BIT
# if defined(__GNUC__) && defined(__i386__)
static __inline__ Uint64
CGI_Swap64(Uint64 x)
{
	union { 
		struct { Uint32 a, b; } s;
		Uint64 u;
	} v;
	v.u = x;
	__asm__("bswapl %0 ; bswapl %1 ; xchgl %0,%1" :
	        "=r" (v.s.a), "=r" (v.s.b) :
		"0" (v.s.a), "1" (v.s.b)); 
	return (v.u);
}
# elif defined(__GNUC__) && defined(__x86_64__)
static __inline__ Uint64
CGI_Swap64(Uint64 x)
{
	__asm__("bswapq %0" :
	        "=r" (x) :
		"0" (x));
	return (x);
}
# else /* !MD */
static __inline__ Uint64
CGI_Swap64(Uint64 x)
{
	Uint32 high, low;

	low = (Uint32)(x & 0xFFFFFFFF);
	x >>= 32;
	high = (Uint32)(x & 0xFFFFFFFF);
	x = CGI_Swap32(low);
	x <<= 32;
	x |= CGI_Swap32(high);
	return (x);
}
# endif /* MD */
#endif /* HAVE_64BIT */

/*
 * Swap floating-point types.
 */
static __inline__ float
CGI_SwapFLT(float v)
{
	union { Uint32 i; float v; } u;

	u.v = v;
	u.i = CGI_Swap32(u.i);
	return (u.v);
}

#ifdef HAVE_64BIT
static __inline__ double
CGI_SwapDBL(double v)
{
	union { Uint64 i; double v; } u;
	
	u.v = v;
	u.i = CGI_Swap64(u.i);
	return (u.v);
}
#else
static __inline__ double
CGI_SwapDBL(double v)
{
	union { Uint8 data[8]; double v; } uIn;
	union { Uint8 data[8]; double v; } uOut;
	int i;
	
	uIn.v = v;
	for (i = 0; i < 8; i++) {
		uOut.data[i] = uIn.data[7-i];
	}
	return (uOut.v);
}
#endif /* HAVE_64BIT */

#ifdef HAVE_LONG_DOUBLE
static __inline__ long double
CGI_SwapLDBL(long double v)
{
	union { Uint8 data[10]; long double v; } uIn;
	union { Uint8 data[10]; long double v; } uOut;
	int i;

	uIn.v = v;
	for (i = 0; i < 10; i++) {
		uOut.data[i] = uIn.data[9-i];
	}
	return (uOut.v);
}
#endif /* HAVE_LONG_DOUBLE */

__END_DECLS

#if CGI_BYTEORDER == CGI_BIG_ENDIAN
# define CGI_SwapLE16(X)	CGI_Swap16(X)
# define CGI_SwapLE32(X)	CGI_Swap32(X)
# define CGI_SwapLE64(X)	CGI_Swap64(X)
# define CGI_SwapLEFLT(X)	CGI_SwapFLT(X)
# define CGI_SwapLEDBL(X)	CGI_SwapDBL(X)
# define CGI_SwapLELDBL(X)	CGI_SwapLDBL(X)
# define CGI_SwapBE16(X)	(X)
# define CGI_SwapBE32(X)	(X)
# define CGI_SwapBE64(X)	(X)
# define CGI_SwapBEFLT(X)	(X)
# define CGI_SwapBEDBL(X)	(X)
# define CGI_SwapBELDBL(X)	(X)
#else
# define CGI_SwapLE16(X)	(X)
# define CGI_SwapLE32(X)	(X)
# define CGI_SwapLE64(X)	(X)
# define CGI_SwapLEFLT(X)	(X)
# define CGI_SwapLEDBL(X)	(X)
# define CGI_SwapLELDBL(X)	(X)
# define CGI_SwapBE16(X)	CGI_Swap16(X)
# define CGI_SwapBE32(X)	CGI_Swap32(X)
# define CGI_SwapBE64(X)	CGI_Swap64(X)
# define CGI_SwapBEFLT(X)	CGI_SwapFLT(X)
# define CGI_SwapBEDBL(X)	CGI_SwapDBL(X)
# define CGI_SwapBELDBL(X)	CGI_SwapLDBL(X)
#endif

#endif /* _LIBPERCGI_BYTESWAP_H_ */