gdb 6.4 not allowing me to change the value of registers like $SP,$RBP and $RIP.

["Kalpana Ramamurthy" <kal_pana at hotmail dot com>]

I have a core dump whose registers look like this when I say "info reg" when 
I give this command in gdb 6.4.

(gdb) info reg
rax            0x0      0
rbx            0x9c960a98       2627078808
rcx            0x2      2
rdx            0x0      0
rsi            0x4e1    1249
rdi            0xfee00300       4276093696
rbp            0x9c960a88       0x9c960a88
rsp            0x9c960a50       0x9c960a50
r8             0x1      1
r9             0x3      3
r10            0x0      0
r11            0x216    534
r12            0x9c960be8       2627079144
r13            0x3      3
r14            0x1      1
r15            0x0      0
rip            0x16489d 0x16489d <PANIC+51>
eflags         0x46     70
cs             0x8      8
ss             0x0      0
ds             0x0      0
es             0x0      0
fs             0x0      0
---Type <return> to continue, or q <return> to quit---
gs             0x0      0

I want to change the value of $rsp from 0x9c960a50  to 0x6d04ee0. But gdb is 
not allowing me
to do that. When I say
(gdb) set $sp=0x6d04ee0
or if I say
(gdb) set $rsp=0x6d04ee0
gdb just refuses to change the values and $sp ($rsp) stays on as 0x9c960a50.

I am using gdb 6.4. When I do the same thing as above using gdb 6.0, it 
works great. I am able
to change the values of the registers. Why does this happen only in gdb 6.4 
? I am not able to write macros because of this problem. Please help - where 
am I going wrong ? I have been debugging gdb 6.4 source code for 3 whole 
days now and its driving me nuts. I could see the registers in the regcache 
- and SP shows the new value. From the regcache onwards
I have no idea how gdb translates the contents of the register cache to 
permanent values
where the globals like$rsp etc get set permanently unless we change it back 
again.

Any help will be really appreciated.

Kalpana
====

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