blargg_endian.h

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// CPU Byte Order Utilities
 
#ifndef BLARGG_ENDIAN
#define BLARGG_ENDIAN
 
#include "blargg_common.h"
 
// BLARGG_CPU_CISC: Defined if CPU has very few general-purpose registers (< 16)
#if defined (__i386__) || defined (__x86_64__) || defined (_M_IX86) || defined (_M_X64)
        #define BLARGG_CPU_X86 1
        #define BLARGG_CPU_CISC 1
#endif
 
#if defined (__powerpc__) || defined (__ppc__) || defined (__ppc64__) || \
                defined (__POWERPC__) || defined (__powerc)
        #define BLARGG_CPU_POWERPC 1
        #define BLARGG_CPU_RISC 1
#endif
 
// BLARGG_BIG_ENDIAN, BLARGG_LITTLE_ENDIAN: Determined automatically, otherwise only
// one may be #defined to 1. Only needed if something actually depends on byte order.
#if !defined (BLARGG_BIG_ENDIAN) && !defined (BLARGG_LITTLE_ENDIAN)
#ifdef __GLIBC__
        // GCC handles this for us
        #include <endian.h>
        #if __BYTE_ORDER == __LITTLE_ENDIAN
                #define BLARGG_LITTLE_ENDIAN 1
        #elif __BYTE_ORDER == __BIG_ENDIAN
                #define BLARGG_BIG_ENDIAN 1
        #endif
#else
 
#if defined (LSB_FIRST) || defined (__LITTLE_ENDIAN__) || BLARGG_CPU_X86 || \
                (defined (LITTLE_ENDIAN) && LITTLE_ENDIAN+0 != 1234)
        #define BLARGG_LITTLE_ENDIAN 1
#endif
 
#if defined (MSB_FIRST)     || defined (__BIG_ENDIAN__) || defined (WORDS_BIGENDIAN) || \
        defined (__sparc__)     ||  BLARGG_CPU_POWERPC || \
        (defined (BIG_ENDIAN) && BIG_ENDIAN+0 != 4321)
        #define BLARGG_BIG_ENDIAN 1
#elif !defined (__mips__)
        // No endian specified; assume little-endian, since it's most common
        #define BLARGG_LITTLE_ENDIAN 1
#endif
#endif
#endif
 
#if BLARGG_LITTLE_ENDIAN && BLARGG_BIG_ENDIAN
        #undef BLARGG_LITTLE_ENDIAN
        #undef BLARGG_BIG_ENDIAN
#endif
 
inline void blargg_verify_byte_order()
{
        #ifndef NDEBUG
                #if BLARGG_BIG_ENDIAN
                        volatile int i = 1;
                        assert( *(volatile char*) &i == 0 );
                #elif BLARGG_LITTLE_ENDIAN
                        volatile int i = 1;
                        assert( *(volatile char*) &i != 0 );
                #endif
        #endif
}
 
inline unsigned get_le16( void const* p )
{
        return  (unsigned) ((unsigned char const*) p) [1] << 8 |
                        (unsigned) ((unsigned char const*) p) [0];
}
 
inline unsigned get_be16( void const* p )
{
        return  (unsigned) ((unsigned char const*) p) [0] << 8 |
                        (unsigned) ((unsigned char const*) p) [1];
}
 
inline blargg_ulong get_le32( void const* p )
{
        return  (blargg_ulong) ((unsigned char const*) p) [3] << 24 |
                        (blargg_ulong) ((unsigned char const*) p) [2] << 16 |
                        (blargg_ulong) ((unsigned char const*) p) [1] <<  8 |
                        (blargg_ulong) ((unsigned char const*) p) [0];
}
 
inline blargg_ulong get_be32( void const* p )
{
        return  (blargg_ulong) ((unsigned char const*) p) [0] << 24 |
                        (blargg_ulong) ((unsigned char const*) p) [1] << 16 |
                        (blargg_ulong) ((unsigned char const*) p) [2] <<  8 |
                        (blargg_ulong) ((unsigned char const*) p) [3];
}
 
inline void set_le16( void* p, unsigned n )
{
        ((unsigned char*) p) [1] = (unsigned char) (n >> 8);
        ((unsigned char*) p) [0] = (unsigned char) n;
}
 
inline void set_be16( void* p, unsigned n )
{
        ((unsigned char*) p) [0] = (unsigned char) (n >> 8);
        ((unsigned char*) p) [1] = (unsigned char) n;
}
 
inline void set_le32( void* p, blargg_ulong n )
{
        ((unsigned char*) p) [0] = (unsigned char) n;
        ((unsigned char*) p) [1] = (unsigned char) (n >> 8);
        ((unsigned char*) p) [2] = (unsigned char) (n >> 16);
        ((unsigned char*) p) [3] = (unsigned char) (n >> 24);
}
 
inline void set_be32( void* p, blargg_ulong n )
{
        ((unsigned char*) p) [3] = (unsigned char) n;
        ((unsigned char*) p) [2] = (unsigned char) (n >> 8);
        ((unsigned char*) p) [1] = (unsigned char) (n >> 16);
        ((unsigned char*) p) [0] = (unsigned char) (n >> 24);
}
 
#if BLARGG_NONPORTABLE
        // Optimized implementation if byte order is known
        #if BLARGG_LITTLE_ENDIAN
                #define GET_LE16( addr )        (*(uint16_t*) (addr))
                #define GET_LE32( addr )        (*(uint32_t*) (addr))
                #define SET_LE16( addr, data )  (void) (*(uint16_t*) (addr) = (data))
                #define SET_LE32( addr, data )  (void) (*(uint32_t*) (addr) = (data))
        #elif BLARGG_BIG_ENDIAN
                #define GET_BE16( addr )        (*(uint16_t*) (addr))
                #define GET_BE32( addr )        (*(uint32_t*) (addr))
                #define SET_BE16( addr, data )  (void) (*(uint16_t*) (addr) = (data))
                #define SET_BE32( addr, data )  (void) (*(uint32_t*) (addr) = (data))
                
                #if BLARGG_CPU_POWERPC
                        // PowerPC has special byte-reversed instructions
                        #if defined (__MWERKS__)
                                #define GET_LE16( addr )        (__lhbrx( addr, 0 ))
                                #define GET_LE32( addr )        (__lwbrx( addr, 0 ))
                                #define SET_LE16( addr, in )    (__sthbrx( in, addr, 0 ))
                                #define SET_LE32( addr, in )    (__stwbrx( in, addr, 0 ))
                        #elif defined (__GNUC__)
                                #define GET_LE16( addr )        ({unsigned short ppc_lhbrx_; __asm__ volatile( "lhbrx %0,0,%1" : "=r" (ppc_lhbrx_) : "r" (addr) : "memory" ); ppc_lhbrx_;})
                                #define GET_LE32( addr )        ({unsigned short ppc_lwbrx_; __asm__ volatile( "lwbrx %0,0,%1" : "=r" (ppc_lwbrx_) : "r" (addr) : "memory" ); ppc_lwbrx_;})
                                #define SET_LE16( addr, in )    ({__asm__ volatile( "sthbrx %0,0,%1" : : "r" (in), "r" (addr) : "memory" );})
                                #define SET_LE32( addr, in )    ({__asm__ volatile( "stwbrx %0,0,%1" : : "r" (in), "r" (addr) : "memory" );})
                        #endif
                #endif
        #endif
#endif
 
#ifndef GET_LE16
        #define GET_LE16( addr )        get_le16( addr )
        #define SET_LE16( addr, data )  set_le16( addr, data )
#endif
 
#ifndef GET_LE32
        #define GET_LE32( addr )        get_le32( addr )
        #define SET_LE32( addr, data )  set_le32( addr, data )
#endif
 
#ifndef GET_BE16
        #define GET_BE16( addr )        get_be16( addr )
        #define SET_BE16( addr, data )  set_be16( addr, data )
#endif
 
#ifndef GET_BE32
        #define GET_BE32( addr )        get_be32( addr )
        #define SET_BE32( addr, data )  set_be32( addr, data )
#endif
 
// auto-selecting versions
 
inline void set_le( uint16_t* p, unsigned     n ) { SET_LE16( p, n ); }
inline void set_le( uint32_t* p, blargg_ulong n ) { SET_LE32( p, n ); }
inline void set_be( uint16_t* p, unsigned     n ) { SET_BE16( p, n ); }
inline void set_be( uint32_t* p, blargg_ulong n ) { SET_BE32( p, n ); }
inline unsigned     get_le( uint16_t* p ) { return GET_LE16( p ); }
inline blargg_ulong get_le( uint32_t* p ) { return GET_LE32( p ); }
inline unsigned     get_be( uint16_t* p ) { return GET_BE16( p ); }
inline blargg_ulong get_be( uint32_t* p ) { return GET_BE32( p ); }
 
#endif