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FIQ & IRQ

Hi all,

can anybody tell me, what is the actual difference between FIQ & IRQ?

Means how FIQ have fast execution time than IRQ? Is there any hardware changes for FIQ, that increases its execution speed? Which factor improve the speed of FIQ?

If any good documentation is available please tell me.

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0 Scott Douglass over 15 years ago
The ARM ARM (Architecture Reference Manual) is the ultimate documentation :-)
<infocenter.arm.com/.../index.html

In short, FIQ is:

higher priority than IRQ: FIQ is masked by fewer exceptions and if FIQ & IRQ happen together FIQ goes first

has more banked registers available than IRQ: fewer registers to save/restore

has a more convenient vector location: no initial branch is needed
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0 Scott Douglass over 15 years ago
The ARM ARM (Architecture Reference Manual) is the ultimate documentation :-)
<infocenter.arm.com/.../index.html

In short, FIQ is:

higher priority than IRQ: FIQ is masked by fewer exceptions and if FIQ & IRQ happen together FIQ goes first

has more banked registers available than IRQ: fewer registers to save/restore

has a more convenient vector location: no initial branch is needed
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0 Shital B over 15 years ago in reply to Scott Douglass

Thanks for reply
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