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/*

 *  C library memcpy routine

 *

 *  This routine has code to optimize performance on the CPU32+

 *  and another version for other 68k machines.

 *

 *  It could be optimized more for machines with MOVE16 instructions.

 *

 *  The routine is placed in this source directory to ensure that it

 *  is picked up by all applications.

 *

 *  W. Eric Norum

 *  Saskatchewan Accelerator Laboratory

 *  University of Saskatchewan

 *  Saskatoon, Saskatchewan, CANADA

 *  eric@skatter.usask.ca

 */

#include <string.h>

#include <rtems/score/m68k.h>

#if defined(__mcpu32__)

#define COPYSETUP(n)    n--

#define COPY(to,from,n,size) \

        asm volatile ("1:\n" \

             "\tmove." size " (%0)+,(%1)+\n" \

             "\tdbf %2,1b\n"  \

             "\tsub.l #0x10000,%2\n" \

             "\tbpl.b 1b\n" : \

                "=a" (from), "=a" (to), "=d" (n) :\

                 "0" (from),  "1" (to), "2" (n) : \

                 "cc", "memory")

#else

#define COPYSETUP(n)

#define COPY(to,from,n,size) \

        asm volatile ("1:\n" \

             "\tmove." size " (%0)+,(%1)+\n" \

             "\tsubq.l #1,%2\n\tbne.b 1b\n" : \

                "=a" (from), "=a" (to), "=d" (n) :\

                 "0" (from),  "1" (to), "2" (n) : \

                 "cc", "memory")

#endif

void *

memcpy(void *s1, const void *s2, size_t n)

{

        char *p1 = s1;

        const char *p2 = s2;

        if (n) {

                if (n < 16) {

                        COPYSETUP (n);

                        COPY (p1, p2, n, "b");

                }

                else {

                        int nbyte;

                        int nl;

                        nbyte = (int)p1 & 0x3;

                        if (nbyte) {

                                nbyte = 4 - nbyte;

                                n -= nbyte;

                                COPYSETUP (nbyte);

                                COPY (p1, p2, nbyte, "b");

                        }

#if (M68K_HAS_MISALIGNED == 0)

                        /*

                         * Take care of machines that can't

                         * handle misaligned references.

                         */

                        if ((int)p2 & 0x1) {

                                COPYSETUP (n);

                                COPY (p1, p2, n, "b");

                                return s1;

                        }

#endif

                        nl = (unsigned int)n >> 2;

                        COPYSETUP (nl);

                        COPY (p1, p2, nl, "l");

                        nbyte = (int)n & 0x3;

                        if (nbyte) {

                                COPYSETUP (nbyte);

                                COPY (p1, p2, nbyte, "b");

                        }

                }

        }

        return s1;

}