FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/icp/algs/skein/skein_port.h

     /*
      * Platform-specific definitions for Skein hash function.
      *
      * Source code author: Doug Whiting, 2008.
      *
      * This algorithm and source code is released to the public domain.
      *
      * Many thanks to Brian Gladman for his portable header files.
      *
     * To port Skein to an "unsupported" platform, change the definitions
     * in this file appropriately.
     */
    /* Copyright 2013 Doug Whiting. This code is released to the public domain. */
    
    #ifndef _SKEIN_PORT_H_
    #define _SKEIN_PORT_H_
    
    #include <sys/types.h>  /* get integer type definitions */
    
    #ifndef RotL_64
    #define RotL_64(x, N)   (((x) << (N)) | ((x) >> (64 - (N))))
    #endif
    
    /*
     * Skein is "natively" little-endian (unlike SHA-xxx), for optimal
     * performance on x86 CPUs. The Skein code requires the following
     * definitions for dealing with endianness:
     *
     *    SKEIN_NEED_SWAP:  0 for little-endian, 1 for big-endian
     *    Skein_Put64_LSB_First
     *    Skein_Get64_LSB_First
     *    Skein_Swap64
     *
     * If SKEIN_NEED_SWAP is defined at compile time, it is used here
     * along with the portable versions of Put64/Get64/Swap64, which
     * are slow in general.
     *
     * Otherwise, an "auto-detect" of endianness is attempted below.
     * If the default handling doesn't work well, the user may insert
     * platform-specific code instead (e.g., for big-endian CPUs).
     *
     */
    #ifndef SKEIN_NEED_SWAP         /* compile-time "override" for endianness? */
    
    #include <sys/isa_defs.h>       /* get endianness selection */
    
    #if     defined(_ZFS_BIG_ENDIAN)
    /* here for big-endian CPUs */
    #define SKEIN_NEED_SWAP   (1)
    #else
    /* here for x86 and x86-64 CPUs (and other detected little-endian CPUs) */
    #define SKEIN_NEED_SWAP   (0)
    #define Skein_Put64_LSB_First(dst08, src64, bCnt) memcpy(dst08, src64, bCnt)
    #define Skein_Get64_LSB_First(dst64, src08, wCnt) \
            memcpy(dst64, src08, 8 * (wCnt))
    #endif
    
    #endif                          /* ifndef SKEIN_NEED_SWAP */
    
    /*
     * Provide any definitions still needed.
     */
    #ifndef Skein_Swap64    /* swap for big-endian, nop for little-endian */
    #if     SKEIN_NEED_SWAP
    #define Skein_Swap64(w64)                               \
            (((((uint64_t)(w64)) & 0xFF) << 56) |           \
            (((((uint64_t)(w64)) >> 8) & 0xFF) << 48) |     \
            (((((uint64_t)(w64)) >> 16) & 0xFF) << 40) |    \
            (((((uint64_t)(w64)) >> 24) & 0xFF) << 32) |    \
            (((((uint64_t)(w64)) >> 32) & 0xFF) << 24) |    \
            (((((uint64_t)(w64)) >> 40) & 0xFF) << 16) |    \
            (((((uint64_t)(w64)) >> 48) & 0xFF) << 8) |     \
            (((((uint64_t)(w64)) >> 56) & 0xFF)))
    #else
    #define Skein_Swap64(w64)  (w64)
    #endif
    #endif                          /* ifndef Skein_Swap64 */
    
    #ifndef Skein_Put64_LSB_First
    static inline void
    Skein_Put64_LSB_First(uint8_t *dst, const uint64_t *src, size_t bCnt)
    {
            /*
             * this version is fully portable (big-endian or little-endian),
             * but slow
             */
            size_t n;
    
            for (n = 0; n < bCnt; n++)
                    dst[n] = (uint8_t)(src[n >> 3] >> (8 * (n & 7)));
    }
    #endif                          /* ifndef Skein_Put64_LSB_First */
    
    #ifndef Skein_Get64_LSB_First
    static inline void
    Skein_Get64_LSB_First(uint64_t *dst, const uint8_t *src, size_t wCnt)
    {
            /*
             * this version is fully portable (big-endian or little-endian),
            * but slow
            */
           size_t n;
   
           for (n = 0; n < 8 * wCnt; n += 8)
                   dst[n / 8] = (((uint64_t)src[n])) +
                       (((uint64_t)src[n + 1]) << 8) +
                       (((uint64_t)src[n + 2]) << 16) +
                       (((uint64_t)src[n + 3]) << 24) +
                       (((uint64_t)src[n + 4]) << 32) +
                       (((uint64_t)src[n + 5]) << 40) +
                       (((uint64_t)src[n + 6]) << 48) +
                       (((uint64_t)src[n + 7]) << 56);
   }
   #endif                          /* ifndef Skein_Get64_LSB_First */
   
   #endif  /* _SKEIN_PORT_H_ */

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