Lpc2000

Does anyone know the proper way of exit from debug state to the thumb
running state? This is not described in any available arm documents.

--- In lpc2000@yahoogroups.com, "radoslaw_mitura"
<radoslaw_mitura@y...> wrote:
>
> When I enter debug mode through jtag I made following:
> 01. read R0 (arm or thuumb instruction)
> 02. read PC (arm or thumb instruction)
> 03. If THUMB detected switch to arm (bx)
> 04. read r1 to r14 (arm instructions)
> 05. read cpsr and spsr (arm instructions)
> 06. modify read cpsr to get proper information about mode (arm/thumb 
> bit) - only in host software.
> 
> When I exit from debug state:
> 10. restore r1 to r15 (arm instruction - r15 is modified to reflect 
> correct address after 12)
> 11. restore cpsr
> 12. restore r0 (arm or thumb instruction)
> 
> I have a problem in step 11-13 when I have to restore cpsr. I don't 
> make a jump at the end of restore.
> Do I have to restore cpsr with thumb mode depended on the state I 
> entered the debug state? 
> I don't know if the next instruction after cpsr resore should be also 
> depended on the state I entered debug mode.
> Sometimes when I exit in thumb (I have entered in thumb) I got 
> exception (undefined instruction), but not always. 
> What will happen if the processor receive interrupt durring debug mode -
>  should I exit in the state I entered debug mode or should I check 
> interrupt flag before exit?
> Maybe I'm making something wrong - could someone describe how to do it 
> properly?
>