cmd_setexpr.c 2.5 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. static ulong get_arg(char *s, int w)
  29. {
  30. ulong *p;
  31. /*
  32. * if the parameter starts with a '*' then assume
  33. * it is a pointer to the value we want
  34. */
  35. if (s[0] == '*') {
  36. p = (ulong *)simple_strtoul(&s[1], NULL, 16);
  37. switch (w) {
  38. case 1: return((ulong)(*(uchar *)p));
  39. case 2: return((ulong)(*(ushort *)p));
  40. case 4:
  41. default: return(*p);
  42. }
  43. } else {
  44. return simple_strtoul(s, NULL, 16);
  45. }
  46. }
  47. int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  48. {
  49. ulong a, b;
  50. char buf[16];
  51. int w;
  52. /* Validate arguments */
  53. if ((argc != 5) || (strlen(argv[3]) != 1))
  54. return CMD_RET_USAGE;
  55. w = cmd_get_data_size(argv[0], 4);
  56. a = get_arg(argv[2], w);
  57. b = get_arg(argv[4], w);
  58. switch (argv[3][0]) {
  59. case '|': sprintf(buf, "%lx", (a | b)); break;
  60. case '&': sprintf(buf, "%lx", (a & b)); break;
  61. case '+': sprintf(buf, "%lx", (a + b)); break;
  62. case '^': sprintf(buf, "%lx", (a ^ b)); break;
  63. case '-': sprintf(buf, "%lx", (a - b)); break;
  64. case '*': sprintf(buf, "%lx", (a * b)); break;
  65. case '/': sprintf(buf, "%lx", (a / b)); break;
  66. case '%': sprintf(buf, "%lx", (a % b)); break;
  67. default:
  68. printf("invalid op\n");
  69. return 1;
  70. }
  71. setenv(argv[1], buf);
  72. return 0;
  73. }
  74. U_BOOT_CMD(
  75. setexpr, 5, 0, do_setexpr,
  76. "set environment variable as the result of eval expression",
  77. "[.b, .w, .l] name value1 <op> value2\n"
  78. " - set environment variable 'name' to the result of the evaluated\n"
  79. " express specified by <op>. <op> can be &, |, ^, +, -, *, /, %\n"
  80. " size argument is only meaningful if value1 and/or value2 are memory addresses"
  81. );