Re: Why gdb-7.1 doesn't set hardware watchpoints on i7 CPU (amd64)?

[Yuri <yuri@rawbw.com>]

Please find below the log of the whole session with gdb_7_3-branch (BTW 
it still prints the 7.2 version number).

I used this C++ program:
#include <string.h>

void ms(char *p) {
   memset(p, 0, 1024);
}

main() {
   char buf1[1024];
   buf1[256] = 7;
   ms(buf1);
}

Please also note that with watchpoint active it was taking a long time 
for gdb to restart the program after 'Starting program' line.

Yuri

---- gdb session log ----
[yuri@mybsd ~/gdb]$ gdb ./main
GNU gdb (GDB) 7.2.90.20110630-cvs
Copyright (C) 2011 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later 
<http://gnu.org/licenses/gpl.html>
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
and "show warranty" for details.
This GDB was configured as "x86_64-unknown-freebsd8.2".
For bug reporting instructions, please see:
<http://www.gnu.org/software/gdb/bugs/>...
Reading symbols from /usr/home/yuri/gdb/main...done.
(gdb) b main
Breakpoint 1 at 0x40065b: file main.C, line 9.
(gdb) r
Starting program: /usr/home/yuri/gdb/main

Breakpoint 1, main () at main.C:9
9         buf1[256] = 7;
(gdb) n
10        ms(buf1);
(gdb) p &buf1[256]
$1 = 0x7fffffffddd0 "\a"
(gdb) watch *(char*)0x7fffffffddd0
Watchpoint 2: *(char*)0x7fffffffddd0
(gdb) c
Continuing.
Watchpoint 2: *(char*)0x7fffffffddd0

Old value = 7 '\a'
New value = 0 '\000'
0x0000000800b78074 in memset () from /lib/libc.so.7
(gdb) c
Continuing.
Watchpoint 2: *(char*)0x7fffffffddd0

Old value = 0 '\000'
New value = 1 '\001'
0x0000000800505c6c in ?? () from /libexec/ld-elf.so.1
(gdb) r
The program being debugged has been started already.
Start it from the beginning? (y or n) y
Starting program: /usr/home/yuri/gdb/main
^C
Program received signal SIGINT, Interrupt.
0x0000000800505959 in ?? () from /libexec/ld-elf.so.1
(gdb) quit
A debugging session is active.

         Inferior 1 [process 49302] will be killed.

Quit anyway? (y or n) y