Analog Devices ADSP-BF53x Blackfin, Reference

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ADSP-BF53x/BF56x Blackfin Processor Programming Reference 4-29
Program Sequencer
/* If the handler uses loop 0, it is a good idea to have
it leave LC0 equal to zero at the end. Normally, this will
happen naturally as a loop is fully executed. If LC0 == 0,
then LT0 and LB0 restores will not incur additional cycles.
If LC0 != 0 when the following pops happen, each pop will
incur a ten-cycle “replay” penalty. Popping or writing LC0
always incurs the penalty. */
LT0 = [SP++];
LB0 = [SP++];
LC0 = [SP++]; /* This will cause a “replay,” that is, a
ten-cycle refetch. */
<Restore other registers here>
RTI;
Events and Interrupts
The Event Controller of the processor manages five types of activities or
events:
• Emulation
• Reset
• Nonmaskable interrupts (NMI)
• Exceptions
• Interrupts
Note the word event describes all five types of activities. The Event Con-
troller manages fifteen different events in all: Emulation, Reset, NMI,
Exception, and eleven Interrupts.