memset.c 2.4 KB

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192
  1. /* Copyright (C) 1991, 1997 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. /* Slight modifications for pa-risc linux - Paul Bame <bame@debian.org> */
  16. #include <linux/types.h>
  17. #include <asm/string.h>
  18. #define OPSIZ (BITS_PER_LONG/8)
  19. typedef unsigned long op_t;
  20. void *
  21. memset (void *dstpp, int sc, size_t len)
  22. {
  23. unsigned int c = sc;
  24. long int dstp = (long int) dstpp;
  25. if (len >= 8)
  26. {
  27. size_t xlen;
  28. op_t cccc;
  29. cccc = (unsigned char) c;
  30. cccc |= cccc << 8;
  31. cccc |= cccc << 16;
  32. if (OPSIZ > 4)
  33. /* Do the shift in two steps to avoid warning if long has 32 bits. */
  34. cccc |= (cccc << 16) << 16;
  35. /* There are at least some bytes to set.
  36. No need to test for LEN == 0 in this alignment loop. */
  37. while (dstp % OPSIZ != 0)
  38. {
  39. ((unsigned char *) dstp)[0] = c;
  40. dstp += 1;
  41. len -= 1;
  42. }
  43. /* Write 8 `op_t' per iteration until less than 8 `op_t' remain. */
  44. xlen = len / (OPSIZ * 8);
  45. while (xlen > 0)
  46. {
  47. ((op_t *) dstp)[0] = cccc;
  48. ((op_t *) dstp)[1] = cccc;
  49. ((op_t *) dstp)[2] = cccc;
  50. ((op_t *) dstp)[3] = cccc;
  51. ((op_t *) dstp)[4] = cccc;
  52. ((op_t *) dstp)[5] = cccc;
  53. ((op_t *) dstp)[6] = cccc;
  54. ((op_t *) dstp)[7] = cccc;
  55. dstp += 8 * OPSIZ;
  56. xlen -= 1;
  57. }
  58. len %= OPSIZ * 8;
  59. /* Write 1 `op_t' per iteration until less than OPSIZ bytes remain. */
  60. xlen = len / OPSIZ;
  61. while (xlen > 0)
  62. {
  63. ((op_t *) dstp)[0] = cccc;
  64. dstp += OPSIZ;
  65. xlen -= 1;
  66. }
  67. len %= OPSIZ;
  68. }
  69. /* Write the last few bytes. */
  70. while (len > 0)
  71. {
  72. ((unsigned char *) dstp)[0] = c;
  73. dstp += 1;
  74. len -= 1;
  75. }
  76. return dstpp;
  77. }