[src/trunk]: src New modifiers for the "write" command: /BHL. They act like /...

[phx <phx%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/c37a75e0bbc1
branches:  trunk
changeset: 751330:c37a75e0bbc1
user:      phx <phx%NetBSD.org@localhost>
date:      Sun Jan 31 21:52:23 2010 +0000

description:
New modifiers for the "write" command: /BHL. They act like /bhl but do not
read the old value from memory before writing.

diffstat:

 share/man/man4/ddb.4   |  15 ++++++++++++---
 sys/ddb/db_write_cmd.c |  21 ++++++++++++++-------
 2 files changed, 26 insertions(+), 10 deletions(-)

diffs (96 lines):

diff -r 1a678e4b324d -r c37a75e0bbc1 share/man/man4/ddb.4
--- a/share/man/man4/ddb.4      Sun Jan 31 21:36:38 2010 +0000
+++ b/share/man/man4/ddb.4      Sun Jan 31 21:52:23 2010 +0000
@@ -1,4 +1,4 @@
-.\"    $NetBSD: ddb.4,v 1.133 2010/01/29 10:48:45 wiz Exp $
+.\"    $NetBSD: ddb.4,v 1.134 2010/01/31 21:52:23 phx Exp $
 .\"
 .\" Copyright (c) 1997 - 2009 The NetBSD Foundation, Inc.
 .\" All rights reserved.
@@ -56,7 +56,7 @@
 .\" any improvements or extensions that they make and grant Carnegie Mellon
 .\" the rights to redistribute these changes.
 .\"
-.Dd January 28, 2010
+.Dd January 31, 2010
 .Dt DDB 4
 .Os
 .Sh NAME
@@ -852,7 +852,7 @@
 Watchpoints on user addresses work the best.
 .It Ic whatis Ar address
 Describe what an address is.
-.It Ic write Ns Oo Cm /bhl Oc Ar address Ar expression Oo Ar expression ... Oc
+.It Ic write Ns Oo Cm /bhlBHL Oc Ar address Ar expression Oo Ar expression ... Oc
 Write the
 .Ar expression Ns s
 at succeeding locations.
@@ -867,6 +867,15 @@
 .Cm /l
 is used.
 .Pp
+Specifying the modifiers in upper case,
+.Cm /B ,
+.Cm /H ,
+.Cm /L ,
+will prevent
+.Nm
+from reading the memory location first, which is useful for avoiding
+side effects when writing to I/O memory regions.
+.Pp
 Warning: since there is no delimiter between
 .Ar expression Ns s ,
 strange things may occur.
diff -r 1a678e4b324d -r c37a75e0bbc1 sys/ddb/db_write_cmd.c
--- a/sys/ddb/db_write_cmd.c    Sun Jan 31 21:36:38 2010 +0000
+++ b/sys/ddb/db_write_cmd.c    Sun Jan 31 21:52:23 2010 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: db_write_cmd.c,v 1.23 2009/03/07 22:02:17 ad Exp $     */
+/*     $NetBSD: db_write_cmd.c,v 1.24 2010/01/31 21:52:23 phx Exp $    */
 
 /*
  * Mach Operating System
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_write_cmd.c,v 1.23 2009/03/07 22:02:17 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_write_cmd.c,v 1.24 2010/01/31 21:52:23 phx Exp $");
 
 #include <sys/param.h>
 #include <sys/proc.h>
@@ -49,11 +49,14 @@
        db_expr_t       old_value;
        db_expr_t       new_value;
        int             size;
-       bool            wrote_one = false;
+       bool            wrote_one;
+       bool            show_old_val;
 
        addr = (db_addr_t) address;
+       wrote_one = false;
+       show_old_val = islower((unsigned char)modif[0]);
 
-       switch (modif[0]) {
+       switch (tolower((unsigned char)modif[0])) {
        case 'b':
                size = 1;
                break;
@@ -71,10 +74,14 @@
        }
 
        while (db_expression(&new_value)) {
-               old_value = db_get_value(addr, size, false);
                db_printsym(addr, DB_STGY_ANY, db_printf);
-               db_printf("\t\t%s = ", db_num_to_str(old_value));
-               db_printf("%s\n", db_num_to_str(new_value));
+               if (show_old_val) {
+                       old_value = db_get_value(addr, size, false);
+                       db_printf("\t\t%s = ", db_num_to_str(old_value));
+                       db_printf("%s\n", db_num_to_str(new_value));
+               }
+               else
+                       db_printf("\t\t= %s\n", db_num_to_str(new_value));
                db_put_value(addr, size, new_value);
                addr += size;