common/cmd_setexpr.c

   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 /*
  24  * This file provides a shell like 'expr' function to return.
  25  */
  26
  27 #include <common.h>
  28 #include <config.h>
  29 #include <command.h>
  30
  31 int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
  32 {
  33         ulong a, b;
  34         char buf[16];
  35
  36         /* Validate arguments */
  37         if ((argc != 5) || (strlen(argv[3]) != 1)) {
  38                 printf("Usage:\n%s\n", cmdtp->usage);
  39                 return 1;
  40         }
  41
  42         a = simple_strtoul(argv[2], NULL, 16);
  43         b = simple_strtoul(argv[4], NULL, 16);
  44
  45         switch (argv[3][0]) {
  46         case '|': sprintf(buf, "%lx", (a | b)); break;
  47         case '&': sprintf(buf, "%lx", (a & b)); break;
  48         case '+': sprintf(buf, "%lx", (a + b)); break;
  49         case '^': sprintf(buf, "%lx", (a ^ b)); break;
  50         case '-': sprintf(buf, "%lx", (a - b)); break;
  51         case '*': sprintf(buf, "%lx", (a * b)); break;
  52         case '/': sprintf(buf, "%lx", (a / b)); break;
  53         case '%': sprintf(buf, "%lx", (a % b)); break;
  54         default:
  55                 printf("invalid op\n");
  56                 return 1;
  57         }
  58
  59         setenv(argv[1], buf);
  60
  61         return 0;
  62 }
  63
  64 U_BOOT_CMD(
  65         setexpr, 5, 0, do_setexpr,
  66         "setexpr - set environment variable as the result of eval expression\n",
  67         "name value1 <op> value2\n"
  68         "    - set environment variable 'name' to the result of the evaluated\n"
  69         "      express specified by <op>.  <op> can be &, |, ^, +, -, *, /, %\n"
  70 );