break instruction in mips32

break instruction in mips32

[Monika Chaddha]

Hi All

As per specification of mips32, 'break' instruction should raise the
Breakpoint Exception but gdb6.0 does not raise any break point
exception.

As my understanding in GDB, Breakpoint implementation is done with the
help of break instruction. Whenever user puts any breakpoint the actual
instruction at that point is replaced by break instruction and the
actual instruction is maintained in other list.

If I use break instruction in user program it does not raise any
exception. Does mips32 not support 'BREAK' instruction in GDB.

Thanks & Regards
Monika

Re: break instruction in mips32

[David Daney]

Monika Chaddha wrote:
> Hi All
> 
> As per specification of mips32, 'break' instruction should raise the
> Breakpoint Exception but gdb6.0 does not raise any break point
> exception.
> 
> As my understanding in GDB, Breakpoint implementation is done with the
> help of break instruction. Whenever user puts any breakpoint the actual
> instruction at that point is replaced by break instruction and the
> actual instruction is maintained in other list.
> 
> If I use break instruction in user program it does not raise any
> exception. Does mips32 not support 'BREAK' instruction in GDB.
> 
> Thanks & Regards
> Monika
> 

I am not sure what problems you are having with break, but recent
official versions of binutils and linux kernel had some "issues" WRT
break and the mips32 target.  I don't know how these effect GDB.

The problem is that "break 7" should be converted to SIGFPE, and other
break codes should result in SIGTRAP.  The problem I mention causes the
break 7 to incorrectly SIGTRAP.

This may be of no help, but I thought I would mention it anyhow.

David Daney.

RE: break instruction in mips32

[Monika Chaddha]

Thanks for the reply .I would like to repeat my question.

Can I use break instruction in user program? How GDB will interpret the
difference in break instruction in the user program (asm file) and break
instruction inserted for break points inserted by GDB...

When I use break instruction in my program for mips32 target. It does
not raise break point exception.

Regards
Monika

>-----Original Message-----
>From: gdb-owner@sources.redhat.com
[mailto:gdb-owner@sources.redhat.com] On
>Behalf Of David Daney
>Sent: Friday, August 06, 2004 10:44 PM
>To: Monika Chaddha
>Cc: gdb@sources.redhat.com
>Subject: Re: break instruction in mips32
>
>Monika Chaddha wrote:
>> Hi All
>>
>> As per specification of mips32, 'break' instruction should raise the
>> Breakpoint Exception but gdb6.0 does not raise any break point
>> exception.
>>
>> As my understanding in GDB, Breakpoint implementation is done with
the
>> help of break instruction. Whenever user puts any breakpoint the
actual
>> instruction at that point is replaced by break instruction and the
>> actual instruction is maintained in other list.
>>
>> If I use break instruction in user program it does not raise any
>> exception. Does mips32 not support 'BREAK' instruction in GDB.
>>
>> Thanks & Regards
>> Monika
>>
>
>I am not sure what problems you are having with break, but recent
>official versions of binutils and linux kernel had some "issues" WRT
>break and the mips32 target.  I don't know how these effect GDB.
>
>The problem is that "break 7" should be converted to SIGFPE, and other
>break codes should result in SIGTRAP.  The problem I mention causes the
>break 7 to incorrectly SIGTRAP.
>
>This may be of no help, but I thought I would mention it anyhow.
>
>David Daney.