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 static ulong get_arg(char *s, int w)
  32 {
  33         ulong *p;
  34
  35         /*
  36          * if the parameter starts with a '*' then assume
  37          * it is a pointer to the value we want
  38          */
  39
  40         if (s[0] == '*') {
  41                 p = (ulong *)simple_strtoul(&s[1], NULL, 16);
  42                 switch (w) {
  43                 case 1: return((ulong)(*(uchar *)p));
  44                 case 2: return((ulong)(*(ushort *)p));
  45                 case 4:
  46                 default: return(*p);
  47                 }
  48         } else {
  49                 return simple_strtoul(s, NULL, 16);
  50         }
  51 }
  52
  53 int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char * const argv[])
  54 {
  55         ulong a, b;
  56         char buf[16];
  57         int w;
  58
  59         /* Validate arguments */
  60         if ((argc != 5) || (strlen(argv[3]) != 1))
  61                 return CMD_RET_USAGE;
  62
  63         w = cmd_get_data_size(argv[0], 4);
  64
  65         a = get_arg(argv[2], w);
  66         b = get_arg(argv[4], w);
  67
  68         switch (argv[3][0]) {
  69         case '|': sprintf(buf, "%lx", (a | b)); break;
  70         case '&': sprintf(buf, "%lx", (a & b)); break;
  71         case '+': sprintf(buf, "%lx", (a + b)); break;
  72         case '^': sprintf(buf, "%lx", (a ^ b)); break;
  73         case '-': sprintf(buf, "%lx", (a - b)); break;
  74         case '*': sprintf(buf, "%lx", (a * b)); break;
  75         case '/': sprintf(buf, "%lx", (a / b)); break;
  76         case '%': sprintf(buf, "%lx", (a % b)); break;
  77         default:
  78                 printf("invalid op\n");
  79                 return 1;
  80         }
  81
  82         setenv(argv[1], buf);
  83
  84         return 0;
  85 }
  86
  87 U_BOOT_CMD(
  88         setexpr, 5, 0, do_setexpr,
  89         "set environment variable as the result of eval expression",
  90         "[.b, .w, .l] name value1 <op> value2\n"
  91         "    - set environment variable 'name' to the result of the evaluated\n"
  92         "      express specified by <op>.  <op> can be &, |, ^, +, -, *, /, %\n"
  93         "      size argument is only meaningful if value1 and/or value2 are memory addresses"
  94 );