u-boot/common/cmd_setexpr.c
Kumar Gala d058698fd2 Add setexpr command
Add a simple expr style command that will set an env variable as the result
of the command.  This allows us to do simple math in shell.  The following
operations are supported: &, |, ^, +, -, *, /.

Signed-off-by: Kumar Gala <galak@kernel.crashing.org>
2008-03-25 22:16:15 +01:00

70 lines
2 KiB
C

/*
* Copyright 2008 Freescale Semiconductor, Inc.
*
* See file CREDITS for list of people who contributed to this
* project.
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation; either version 2 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
* MA 02111-1307 USA
*/
/*
* This file provides a shell like 'expr' function to return.
*/
#include <common.h>
#include <config.h>
#include <command.h>
int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
{
ulong a, b;
char buf[16];
/* Validate arguments */
if ((argc != 5) || (strlen(argv[3]) != 1)) {
printf("Usage:\n%s\n", cmdtp->usage);
return 1;
}
a = simple_strtoul(argv[2], NULL, 16);
b = simple_strtoul(argv[4], NULL, 16);
switch (argv[3][0]) {
case '|': sprintf(buf, "%lx", (a | b)); break;
case '&': sprintf(buf, "%lx", (a & b)); break;
case '+': sprintf(buf, "%lx", (a + b)); break;
case '^': sprintf(buf, "%lx", (a ^ b)); break;
case '-': sprintf(buf, "%lx", (a - b)); break;
case '*': sprintf(buf, "%lx", (a * b)); break;
case '/': sprintf(buf, "%lx", (a / b)); break;
case '%': sprintf(buf, "%lx", (a % b)); break;
default:
printf("invalid op\n");
return 1;
}
setenv(argv[1], buf);
return 0;
}
U_BOOT_CMD(
setexpr, 5, 0, do_setexpr,
"setexpr - set environment variable as the result of eval expression\n",
"name value1 <op> value2\n"
" - set environment variable 'name' to the result of the evaluated\n"
" express specified by <op>. <op> can be &, |, ^, +, -, *, /, %\n"
);