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C/C++ Source or Header  |  1992-03-17  |  4KB  |  96 lines
  1. /* memcopy.h -- definitions for memory copy functions.  Motorola 68020 version.
  2.    Copyright (C) 1991 Free Software Foundation, Inc.
  3.    Contributed by Torbjorn Granlund (tege@sics.se).
  4.  
  5. The GNU C Library is free software; you can redistribute it and/or
  6. modify it under the terms of the GNU Library General Public License as
  7. published by the Free Software Foundation; either version 2 of the
  8. License, or (at your option) any later version.
  9.  
  10. The GNU C Library is distributed in the hope that it will be useful,
  11. but WITHOUT ANY WARRANTY; without even the implied warranty of
  12. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13. Library General Public License for more details.
  14.  
  15. You should have received a copy of the GNU Library General Public
  16. License along with the GNU C Library; see the file COPYING.LIB.  If
  17. not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18. Cambridge, MA 02139, USA.  */
  19.  
  20. #include <sysdeps/generic/memcopy.h>
  21.  
  22. #if    defined(__mc68020__) || defined(mc68020)
  23.  
  24. #undef    OP_T_THRES
  25. #define    OP_T_THRES    16
  26.  
  27. /* WORD_COPY_FWD and WORD_COPY_BWD are not symmetric on the 68020,
  28.    because of its weird instruction overlap characteristics.  */
  29.  
  30. #undef    WORD_COPY_FWD
  31. #define WORD_COPY_FWD(dst_bp, src_bp, nbytes_left, nbytes)              \
  32.   do                                          \
  33.     {                                          \
  34.       size_t __nwords = (nbytes) / sizeof (op_t);                  \
  35.       size_t __nblocks = __nwords / 8 + 1;                      \
  36.       dst_bp -= (8 - __nwords % 8) * sizeof (op_t);                  \
  37.       src_bp -= (8 - __nwords % 8) * sizeof (op_t);                  \
  38.       switch (__nwords % 8)                              \
  39.     do                                      \
  40.       {                                      \
  41.         ((op_t *) dst_bp)[0] = ((op_t *) src_bp)[0];              \
  42.       case 7:                                  \
  43.         ((op_t *) dst_bp)[1] = ((op_t *) src_bp)[1];              \
  44.       case 6:                                  \
  45.         ((op_t *) dst_bp)[2] = ((op_t *) src_bp)[2];              \
  46.       case 5:                                  \
  47.         ((op_t *) dst_bp)[3] = ((op_t *) src_bp)[3];              \
  48.       case 4:                                  \
  49.         ((op_t *) dst_bp)[4] = ((op_t *) src_bp)[4];              \
  50.       case 3:                                  \
  51.         ((op_t *) dst_bp)[5] = ((op_t *) src_bp)[5];              \
  52.       case 2:                                  \
  53.         ((op_t *) dst_bp)[6] = ((op_t *) src_bp)[6];              \
  54.       case 1:                                  \
  55.         ((op_t *) dst_bp)[7] = ((op_t *) src_bp)[7];              \
  56.       case 0:                                  \
  57.         src_bp += 32;                              \
  58.         dst_bp += 32;                              \
  59.         __nblocks--;                              \
  60.       }                                      \
  61.       while (__nblocks != 0);                              \
  62.       (nbytes_left) = (nbytes) % sizeof (op_t);                      \
  63.     } while (0)
  64.  
  65. #undef    WORD_COPY_BWD
  66. #define WORD_COPY_BWD(dst_ep, src_ep, nbytes_left, nbytes)              \
  67.   do                                          \
  68.     {                                          \
  69.       size_t __nblocks = (nbytes) / 32 + 1;                      \
  70.       switch ((nbytes) / sizeof (op_t) % 8)                      \
  71.     do                                      \
  72.       {                                      \
  73.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  74.       case 7:                                  \
  75.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  76.       case 6:                                  \
  77.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  78.       case 5:                                  \
  79.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  80.       case 4:                                  \
  81.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  82.       case 3:                                  \
  83.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  84.       case 2:                                  \
  85.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  86.       case 1:                                  \
  87.         *--((op_t *) dst_ep) = *--((op_t *) src_ep);              \
  88.       case 0:                                  \
  89.         __nblocks--;                              \
  90.       }                                      \
  91.       while (__nblocks != 0);                              \
  92.       (nbytes_left) = (nbytes) % sizeof (op_t);                      \
  93.     } while (0)
  94.  
  95. #endif
  96.