cmd_setexpr.c 2.0 KB

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  1. /*
  2. * Copyright 2008 Freescale Semiconductor, Inc.
  3. *
  4. * See file CREDITS for list of people who contributed to this
  5. * project.
  6. *
  7. * This program is free software; you can redistribute it and/or
  8. * modify it under the terms of the GNU General Public License as
  9. * published by the Free Software Foundation; either version 2 of
  10. * the License, or (at your option) any later version.
  11. *
  12. * This program is distributed in the hope that it will be useful,
  13. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  15. * GNU General Public License for more details.
  16. *
  17. * You should have received a copy of the GNU General Public License
  18. * along with this program; if not, write to the Free Software
  19. * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  20. * MA 02111-1307 USA
  21. */
  22. /*
  23. * This file provides a shell like 'expr' function to return.
  24. */
  25. #include <common.h>
  26. #include <config.h>
  27. #include <command.h>
  28. int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
  29. {
  30. ulong a, b;
  31. char buf[16];
  32. /* Validate arguments */
  33. if ((argc != 5) || (strlen(argv[3]) != 1)) {
  34. cmd_usage(cmdtp);
  35. return 1;
  36. }
  37. a = simple_strtoul(argv[2], NULL, 16);
  38. b = simple_strtoul(argv[4], NULL, 16);
  39. switch (argv[3][0]) {
  40. case '|': sprintf(buf, "%lx", (a | b)); break;
  41. case '&': sprintf(buf, "%lx", (a & b)); break;
  42. case '+': sprintf(buf, "%lx", (a + b)); break;
  43. case '^': sprintf(buf, "%lx", (a ^ b)); break;
  44. case '-': sprintf(buf, "%lx", (a - b)); break;
  45. case '*': sprintf(buf, "%lx", (a * b)); break;
  46. case '/': sprintf(buf, "%lx", (a / b)); break;
  47. case '%': sprintf(buf, "%lx", (a % b)); break;
  48. default:
  49. printf("invalid op\n");
  50. return 1;
  51. }
  52. setenv(argv[1], buf);
  53. return 0;
  54. }
  55. U_BOOT_CMD(
  56. setexpr, 5, 0, do_setexpr,
  57. "set environment variable as the result of eval expression",
  58. "name value1 <op> value2\n"
  59. " - set environment variable 'name' to the result of the evaluated\n"
  60. " express specified by <op>. <op> can be &, |, ^, +, -, *, /, %"
  61. );