questions about port rtems to ARM CPU am1707?

[Mick Davis]

On 08/15/2011 10:45 AM, 郑小军 wrote:
> Dear all:
> I am a newbie to rtems, i'm porting rtems to TI's ARM arm1707, now rtems
> can run on my board, but i still have some questions about rtems.
> 1. vector address? in file cpukit\score\cpu\arm\cpu.c
> function _CPU_ISR_install_vector() install vector at address 0x0,but i
> need to install at high address,does rtems provide a standard way to do
> it? i do not find a standard way to do it, so i modify the file
> directly, but i think it is not a good way.

I use a different ARM, but I think if you use mmu_init() then the 
vectors get configured for address 0x0.

> 2. about task context switch time,
> i measure the time use this way:
> task1()
> {
> for(;;)
> {
> wait at a message queue;
> toggle gpio;
> }
> }
> Init()
> {
> ...
> for(;;)
> {
> send message;
> toggle gpio;
> sleep;
> }
> }
> the time is about 27us, i have read a title about the time, but it gives
> the time is about 2~3us.Did I do something wrong?
>       3.how to measure the interrupt context switch time?
>
>
> English is not my native language, hope you can understand what i say.
> And give me some advice about English. thank you .
>
>
>
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-- 

Mick Davis
Goanna Technologies Pty Ltd
+61 8 9444 2634