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Add setexpr command

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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>
This commit is contained in:
Kumar Gala 2008-02-14 20:44:42 -06:00 committed by Wolfgang Denk
parent 0d48926c87
commit d058698fd2
3 changed files with 72 additions and 0 deletions
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1
common/Makefile
View File

@ -88,6 +88,7 @@ COBJS-$(CONFIG_CMD_REGINFO) += cmd_reginfo.o
COBJS-$(CONFIG_CMD_REISER) += cmd_reiser.o
COBJS-y += cmd_sata.o
COBJS-$(CONFIG_CMD_SCSI) += cmd_scsi.o
COBJS-$(CONFIG_CMD_SETEXPR) += cmd_setexpr.o
COBJS-$(CONFIG_CMD_SPI) += cmd_spi.o
COBJS-$(CONFIG_CMD_STRINGS) += cmd_strings.o
COBJS-$(CONFIG_CMD_TERMINAL) += cmd_terminal.o

70
common/cmd_setexpr.c Normal file
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@ -0,0 +1,70 @@
/*
* 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"
);

1
include/config_cmd_all.h
View File

@ -70,6 +70,7 @@
#define CONFIG_CMD_SAVES /* save S record dump */
#define CONFIG_CMD_SCSI /* SCSI Support */
#define CONFIG_CMD_SDRAM /* SDRAM DIMM SPD info printout */
#define CONFIG_CMD_SETEXPR /* setexpr support */
#define CONFIG_CMD_SETGETDCR /* DCR support on 4xx */
#define CONFIG_CMD_SNTP /* SNTP support */
#define CONFIG_CMD_SPI /* SPI utility */