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 <fransmeulenbro...@gmail.com>
---
common/cmd_setexpr.c | 29 +++++++++++++++++++++++++----
1 files changed, 25 insertions(+), 4 deletions(-)
diff --git a/common/cmd_setexpr.c b/common/cmd_setexpr.c
index f8b5d4d..86e371b 100644
--- a/common/cmd_setexpr.c
+++ b/common/cmd_setexpr.c
@@ -28,10 +28,28 @@
#include <config.h>
#include <command.h>
+static ulong get_arg(char *s, int w)
+{
+ ulong *p;
+
+ /* if the parameter starts with a * then assume 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: 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 +57,10 @@ 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 +84,8 @@ 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"
);
--
1.7.0
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