Lpc2000

Bruce Paterson wrote:
>>Dmitry Diky wrote:
>>
>>>As I know FIQ mode used banked r8-r14 registers and no 
>>
>>registers have 
> 
> 
> Steb replied:
> 
>>Uuuuuuuuuhhhhhhh, ... Are you sure you know what you are doing?
>>..... (normal) IRQ your system will enter IRQ-mode. In opposite to 
>>other architectures ARM can perform a kind of hardware 
>>context switch by switching to another mode. In general you 
>>should NEVER change those modes manually in your software! 
> 
> 
> I haven't used an FIQ myself yet so excuse the possibly silly question.
> Surely if you are using an alternate register set in an FIQ, at some
> early stage, somewhere, you'd want to initialise those registers (eg.
> Setup a pointer at the start of a circular buffer). How would you
> achieve this if you aren't able to/allowed to switch modes manually ?

Hi Bruce,

it is allowed to switch context manually, during starup for example. But I think it is not
recommended to do this in application code. You must initialize all modes you want to use (FIQ, IRQ,
USR, SVR, SYS) or modes that might be used (for you) (ABT, UND) during startup.

  Sten

-- 
/************************************************
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