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authorFrans Meulenbroeks <fransmeulenbroeks@gmail.com>2010-02-26 14:00:19 +0100
committerWolfgang Denk <wd@denx.de>2010-03-21 22:44:43 +0100
commit47ab5ad14575531798431f0d1e8f83ee9bb0a87e (patch)
tree83edf71dd440464ff9f0f506fab461e14165a497
parent652e53546b23c25f80756287eaf607b713afdc87 (diff)
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cmd_setexpr: allow memory addresses in expressions
This patch add functionality to use memory addresses in expressions. This increases the power of expressions substantially It adheres to the standard convemtions: memory addresses can be given in the format *address (e.g. *1000) Rationale for this change is that it allows masking off bits from a byte that is obtained by reading data from e.g. i2c. Signed-off-by: Frans Meulenbroeks <fransmeulenbroeks@gmail.com> Fix warning: control reaches end of non-void function Signed-off-by: Wolfgang Denk <wd@denx.de>
-rw-r--r--common/cmd_setexpr.c34
1 files changed, 30 insertions, 4 deletions
diff --git a/common/cmd_setexpr.c b/common/cmd_setexpr.c
index f8b5d4d..2d37197 100644
--- a/common/cmd_setexpr.c
+++ b/common/cmd_setexpr.c
@@ -28,10 +28,33 @@
#include <config.h>
#include <command.h>
+static ulong get_arg(char *s, int w)
+{
+ ulong *p;
+
+ /*
+ * if the parameter starts with a '*' then assume
+ * it is a pointer to the value we want
+ */
+
+ if (s[0] == '*') {
+ p = (ulong *)simple_strtoul(&s[1], NULL, 16);
+ switch (w) {
+ case 1: return((ulong)(*(uchar *)p));
+ case 2: return((ulong)(*(ushort *)p));
+ case 4:
+ default: return(*p);
+ }
+ } else {
+ return simple_strtoul(s, NULL, 16);
+ }
+}
+
int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
{
ulong a, b;
char buf[16];
+ int w;
/* Validate arguments */
if ((argc != 5) || (strlen(argv[3]) != 1)) {
@@ -39,8 +62,10 @@ int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
return 1;
}
- a = simple_strtoul(argv[2], NULL, 16);
- b = simple_strtoul(argv[4], NULL, 16);
+ w = cmd_get_data_size(argv[0], 4);
+
+ a = get_arg(argv[2], w);
+ b = get_arg(argv[4], w);
switch (argv[3][0]) {
case '|': sprintf(buf, "%lx", (a | b)); break;
@@ -64,7 +89,8 @@ int do_setexpr(cmd_tbl_t *cmdtp, int flag, int argc, char *argv[])
U_BOOT_CMD(
setexpr, 5, 0, do_setexpr,
"set environment variable as the result of eval expression",
- "name value1 <op> value2\n"
+ "[.b, .w, .l] name value1 <op> value2\n"
" - set environment variable 'name' to the result of the evaluated\n"
- " express specified by <op>. <op> can be &, |, ^, +, -, *, /, %"
+ " express specified by <op>. <op> can be &, |, ^, +, -, *, /, %\n"
+ " size argument is only meaningful if value1 and/or value2 are memory addresses"
);