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/*

 * memmove routine for Z8000

 * Copyright (C) 2004 Christian Groessler 

 *

 * Permission to use, copy, modify, and distribute this file

 * for any purpose is hereby granted without fee, provided that

 * the above copyright notice and this notice appears in all

 * copies.

 *

 * This file is distributed WITHOUT ANY WARRANTY; without even the implied

 * warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

 */

/* void *memmove(void *dest, const void *src, size_t length);

 */

        name    "memmove.S"

        .text

        even

global  _memmove

_memmove:

#ifdef __Z8001__

        segm

#ifdef __STD_CALL__

        ldl     rr6,rr14(#4)

        ldl     rr4,rr14(#8)

        ldl     rr2,rr14(#12)

#else

        pushl   @rr14,rr6

#endif

/* rr2  - length        (high word ignored)

 * rr4  - src

 * rr6  - dest

 */

        testl   rr2

        jr      z,finish

/*  check for destructive overlap (src < dest && dest < src + length) */

        cpl     rr6,rr4

        jp      ule,memmove_entry       /* non-destructive, let memcpy do the work */

        ldl     rr0,rr2

        addl    rr0,rr4                 /* rr0 = src + length */

        cpl     rr0,rr6

        jp      ult,memmove_entry       /* non-destructive, let memcpy do the work */

/* set-up pointers to copy backwards, add (length - 1) */

        addl    rr4,rr2                 /* src + length */

        addl    rr6,rr2                 /* dest + length */

        subl    rr4,#1

        subl    rr6,#1

/* check alignment */

        bitb    rl7,#0          /* odd destination address? */

        jr      z,testsrc

        bitb    rl5,#0          /* odd source address? */

        jr      z,odd_copy

        jr      even_copy

testsrc:

        bitb    rl5,#0

        jr      nz,odd_copy     /* src even, dest odd */

        lddb    @rr6,@rr4,r3

        jr      ov,finish       /* jump if r5 is zero now */

/* copy words */

even_copy:

        ld      r2,r3                   /* remember length */

        srl     r3,#1

/*      jr      z,no_words         it cannot be zero here */

        dec     r5,#1

        dec     r7,#1

        lddr    @rr6,@rr4,r3

no_words:

        bitb    rl2,#0          /* odd length? */

        jr      z,finish

        inc     r5,#1

        inc     r7,#1

        lddb    @rr6,@rr4,r2    /* yes, copy last byte */

        jr      finish

/* copy bytes */

odd_copy:

        lddrb   @rr6,@rr4,r3

finish:

#ifdef __STD_CALL__

        ldl     rr6,rr14(#4)

#else

        popl    rr2,@rr14

#endif

#else           /* above Z8001, below Z8002 */

        unsegm

#ifdef __STD_CALL__

        ld      r7,r15(#2)

        ld      r6,r15(#4)

        ld      r5,r15(#6)

#else

        ld      r2,r7           /* buffer pointer return value */

#endif

/* r5  - length

 * r6  - src

 * r7  - dest

 */

        test    r5

        jr      z,finish

/*  check for destructive overlap (src < dest && dest < src + length) */

        cp      r7,r6

        jp      ule,memmove_entry       /* non-destructive, let memcpy do the work */

        ld      r0,r5

        add     r0,r6                   /* r0 = src + length */

        cp      r0,r7

        jp      ult,memmove_entry       /* non-destructive, let memcpy do the work */

/* set-up pointers to copy backwards, add (length - 1) */

        add     r6,r5                   /* src + length */

        add     r7,r5                   /* dest + length */

        dec     r6,#1

        dec     r7,#1

/* check alignment */

        bitb    rl7,#0          /* odd destination address? */

        jr      z,testsrc

        bitb    rl6,#0          /* odd source address? */

        jr      z,odd_copy

        jr      even_copy

testsrc:

        bitb    rl6,#0

        jr      nz,odd_copy     /* src even, dest odd */

        lddb    @r7,@r6,r5

        jr      ov,finish       /* jump if r5 is zero now */

/* copy words */

even_copy:

        ld      r4,r5           /* remember length */

        srl     r5,#1

/*      jr      z,no_words         it cannot be zero here */

        dec     r6,#1

        dec     r7,#1

        lddr    @r7,@r6,r5

no_words:

        bitb    rl4,#0          /* odd length? */

        jr      z,finish

        inc     r6,#1

        inc     r7,#1

        lddb    @r7,@r6,r4      /* yes, copy last byte */

        jr      finish

/* copy bytes */

odd_copy:

        lddrb   @r7,@r6,r5

finish:

#ifdef __STD_CALL__

        ld      r7,r15(#2)

#endif

#endif  /* Z8002 */

        ret

        .end