Re: [Qemu-devel] Better Cortex-M support?

[Liviu Ionescu]

On 29 Oct 2014, at 17:31, Paolo Bonzini <address@hidden> wrote:

> That's due to usage of the breakpoint instruction, as Peter pointed out.

>> Are we treating the
>> breakpoint as a breakpoint and dropping into gdb
>> rather than treating it as a semihosting call?

my first thought was that the semihosting BRKs go to GDB, but execution does 
not stop at these places, the semihosting BRKs seem ignored.

from my tests GDB looks normal, no unexpected breaks.

just that nothing is displayed on the semihosting output.

> I mean that writes to ROM or flash via gdb should modify the ROM
> directly, unlike writes by the CPU.

you may be right, but I don't see the point related to semihosting, in this 
case the BRKs are permanent in flash.

but if you understand these implementation details, could you suggest a fix?

you can use the same executable I used for tests 
(https://dl.dropboxusercontent.com/u/78151643/minimal.elf), it does a lot of 
semihosting tracing.


regards,

Liviu