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>

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>
Frans Meulenbroeks · Wolfgang Denk · Eric Lee
1 parent 652e53546b
Showing 1 changed file with 30 additions and 4 deletions Side-by-side Diff
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)) {
  
@@ -39,9 +62,11 @@
 		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;
 	case '&': sprintf(buf, "%lx", (a & b)); break;
  
@@ -64,8 +89,9 @@
 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"
 );
...	...	@@ -28,10 +28,33 @@
28	28	#include <config.h>
29	29	#include <command.h>
30	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	+
31	53	int do_setexpr(cmd_tbl_t cmdtp, int flag, int argc, char argv[])
32	54	{
33	55	ulong a, b;
34	56	char buf[16];
	57	+ int w;
35	58
36	59	/* Validate arguments */
37	60	if ((argc != 5) \|\| (strlen(argv[3]) != 1)) {
38	61
...	...	@@ -39,9 +62,11 @@
39	62	return 1;
40	63	}
41	64
42		- a = simple_strtoul(argv[2], NULL, 16);
43		- b = simple_strtoul(argv[4], NULL, 16);
	65	+ w = cmd_get_data_size(argv[0], 4);
44	66
	67	+ a = get_arg(argv[2], w);
	68	+ b = get_arg(argv[4], w);
	69	+
45	70	switch (argv[3][0]) {
46	71	case '\|': sprintf(buf, "%lx", (a \| b)); break;
47	72	case '&': sprintf(buf, "%lx", (a & b)); break;
48	73
...	...	@@ -64,8 +89,9 @@
64	89	U_BOOT_CMD(
65	90	setexpr, 5, 0, do_setexpr,
66	91	"set environment variable as the result of eval expression",
67		- "name value1 <op> value2\n"
	92	+ "[.b, .w, .l] name value1 <op> value2\n"
68	93	" - set environment variable 'name' to the result of the evaluated\n"
69		- " express specified by <op>. <op> can be &, \|, ^, +, -, *, /, %"
	94	+ " express specified by <op>. <op> can be &, \|, ^, +, -, *, /, %\n"
	95	+ " size argument is only meaningful if value1 and/or value2 are memory addresses"
70	96	);