memset.c 2.3 KB

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  1. /* Copyright (C) 1991, 1997, 2003 Free Software Foundation, Inc.
  2. This file is part of the GNU C Library.
  3. The GNU C Library is free software; you can redistribute it and/or
  4. modify it under the terms of the GNU Lesser General Public
  5. License as published by the Free Software Foundation; either
  6. version 2.1 of the License, or (at your option) any later version.
  7. The GNU C Library is distributed in the hope that it will be useful,
  8. but WITHOUT ANY WARRANTY; without even the implied warranty of
  9. MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
  10. Lesser General Public License for more details.
  11. You should have received a copy of the GNU Lesser General Public
  12. License along with the GNU C Library; if not, write to the Free
  13. Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  14. 02111-1307 USA. */
  15. #include <string.h>
  16. #include "memcopy.h"
  17. libc_hidden_proto(memset)
  18. void *memset (void *dstpp, int c, size_t len)
  19. {
  20. long int dstp = (long int) dstpp;
  21. if (len >= 8)
  22. {
  23. size_t xlen;
  24. op_t cccc;
  25. cccc = (unsigned char) c;
  26. cccc |= cccc << 8;
  27. cccc |= cccc << 16;
  28. if (OPSIZ > 4)
  29. /* Do the shift in two steps to avoid warning if long has 32 bits. */
  30. cccc |= (cccc << 16) << 16;
  31. /* There are at least some bytes to set.
  32. No need to test for LEN == 0 in this alignment loop. */
  33. while (dstp % OPSIZ != 0)
  34. {
  35. ((byte *) dstp)[0] = c;
  36. dstp += 1;
  37. len -= 1;
  38. }
  39. /* Write 8 `op_t' per iteration until less than 8 `op_t' remain. */
  40. xlen = len / (OPSIZ * 8);
  41. while (xlen > 0)
  42. {
  43. ((op_t *) dstp)[0] = cccc;
  44. ((op_t *) dstp)[1] = cccc;
  45. ((op_t *) dstp)[2] = cccc;
  46. ((op_t *) dstp)[3] = cccc;
  47. ((op_t *) dstp)[4] = cccc;
  48. ((op_t *) dstp)[5] = cccc;
  49. ((op_t *) dstp)[6] = cccc;
  50. ((op_t *) dstp)[7] = cccc;
  51. dstp += 8 * OPSIZ;
  52. xlen -= 1;
  53. }
  54. len %= OPSIZ * 8;
  55. /* Write 1 `op_t' per iteration until less than OPSIZ bytes remain. */
  56. xlen = len / OPSIZ;
  57. while (xlen > 0)
  58. {
  59. ((op_t *) dstp)[0] = cccc;
  60. dstp += OPSIZ;
  61. xlen -= 1;
  62. }
  63. len %= OPSIZ;
  64. }
  65. /* Write the last few bytes. */
  66. while (len > 0)
  67. {
  68. ((byte *) dstp)[0] = c;
  69. dstp += 1;
  70. len -= 1;
  71. }
  72. return dstpp;
  73. }
  74. libc_hidden_def(memset)