nt-lite/code/kernel/hal/hal_processor.c

// HAL processor control exports. This file owns interrupt masking and processor halt instructions.

#include <stdint.h>
#include <intrin.h>
#include <ntlite/ddi/hal_api.h>
#pragma intrinsic(_disable)
#pragma intrinsic(_enable)

// Masks interrupts and returns the previous RFLAGS value.
__declspec(dllexport) uintptr_t HalDisableInterrupts(void) {
    uintptr_t flags = __readeflags();
    _disable();
    return flags;
}

// Restores a previously saved RFLAGS value.
__declspec(dllexport) void HalRestoreInterrupts(uintptr_t flags) {
    __writeeflags(flags);
}

// Enables maskable interrupts.
__declspec(dllexport) void HalEnableInterrupts(void) {
    _enable();
}

// Enables interrupts and halts until an interrupt arrives.
__declspec(dllexport) void HalWaitForInterrupt(void) {
    _enable();
    __halt();
}

// Halts once without changing interrupt state.
__declspec(dllexport) void HalHalt(void) {
    __halt();
}

// Masks interrupts and permanently stops the current processor.
__declspec(dllexport) _Noreturn void HalStopProcessor(void) {
    _disable();
    for (;;)
        __halt();
}