OS Primitives: Interrupt Handling#

IRQs And ISRs#

Interrupt service routine (ISR): callback void(int irqnum)
Attached to an Interrupt request (IRQ) irqnum
Called asynchronously (run at the most inopportune time)
IRQ should safely be considered parallel (though varies per architecture)

code/isrdemo.cpp#

#include <why-irq.h>
#include <why-time.h>
#include <print>


int main()
{
    Why::init();

    auto isr = [](int irqnum){
        std::println("seeing interrupt #{}", irqnum);
    };

    Why::IRQ::connect(2, isr);                         // <-- activate ISR

    Why::pause();                                      // <-- main loop
    return 0;
}

In why-shell#

> irq 2
seeing interrupt #2
>