Lpc2000

At 02:50 PM 8/11/04 +0000, you wrote:

>   ldr pc, [pc, #irq_handler_address - . - 8] ----------->  TO LDR PC,
>[PC, #-0xFF0]
>
>------------------------------------------------------------------
>
>I don't understand the mean of this modificication but it works ?
>Why #-0xFF0 ?
>What's that syntax : _ . - 8 ?

ldr     pc, [pc, #-0xFF0]

loads the program counter with the values read from the location of (PC - 
0xff0).  Essentially an indirect jump.  That location (PC - 0xff0) is the 
address of the VIC register that holds the vector for the interrupt that is 
currently the highest priority IRQ.

Robert

" 'Freedom' has no meaning of itself.  There are always restrictions,
be they legal, genetic, or physical.  If you don't believe me, try to
chew a radio signal. "

                         Kelvin Throop, III