interrupt_disabler.h

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#pragma once
 
#include "di/types/prelude.h"
 
namespace iris {
namespace arch {
    constexpr inline di::u64 interrupt_enable_flag = 1 << 9;
}
 
static inline void raw_enable_interrupts() {
    asm volatile("sti");
}
 
static inline void raw_disable_interrupts() {
    asm volatile("cli");
}
 
static inline auto interrupts_disabled() -> bool {
    di::u64 rflags;
    asm volatile("pushfq\n"
                 "pop %0\n"
                 : "=r"(rflags)
                 :
                 : "cc");
    return (rflags & arch::interrupt_enable_flag) == 0U;
}
 
static inline auto raw_disable_interrupts_and_save_previous_state() -> bool {
    di::u64 rflags;
    asm volatile("pushfq\n"
                 "pop %0\n"
                 : "=r"(rflags)
                 :
                 : "cc");
    if (!(rflags & arch::interrupt_enable_flag)) {
        return true;
    }
    raw_disable_interrupts();
    return false;
}
 
class InterruptDisabler {
public:
    InterruptDisabler() { m_had_interrupts_disabled = raw_disable_interrupts_and_save_previous_state(); }
 
    ~InterruptDisabler() {
        if (!m_had_interrupts_disabled) {
            raw_enable_interrupts();
        }
    }
 
private:
    bool m_had_interrupts_disabled { false };
};
}