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Make missing a vblank interrupt wait less painful

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This commit is contained in:
Gwilym Kuiper 2023-01-12 21:20:54 +00:00
parent 832ad13e12
commit e50540752c
1 changed files with 26 additions and 10 deletions
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36
agb/src/interrupt.rs
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@ -7,7 +7,7 @@ use core::{
use alloc::boxed::Box;
use bare_metal::CriticalSection;
use crate::{display::DISPLAY_STATUS, memory_mapped::MemoryMapped};
use crate::{display::DISPLAY_STATUS, memory_mapped::MemoryMapped, sync::Static};
#[derive(Clone, Copy)]
pub enum Interrupt {
@ -308,27 +308,43 @@ where
r
}
static NUM_VBLANKS: Static<usize> = Static::new(0); // overflows after 2.27 years
static HAS_CREATED_INTERRUPT: Static<bool> = Static::new(false);
#[non_exhaustive]
pub struct VBlank {}
pub struct VBlank {
last_waited_number: Cell<usize>,
}
impl VBlank {
/// Handles setting up everything required to be able to use the wait for
/// interrupt syscall.
#[must_use]
pub fn get() -> Self {
interrupt_to_root(Interrupt::VBlank).add();
VBlank {}
if !HAS_CREATED_INTERRUPT.read() {
let handler = add_interrupt_handler(Interrupt::VBlank, |_| {
NUM_VBLANKS.write(NUM_VBLANKS.read() + 1);
});
core::mem::forget(handler);
HAS_CREATED_INTERRUPT.write(true);
}
VBlank {
last_waited_number: Cell::new(NUM_VBLANKS.read()),
}
}
/// Pauses CPU until vblank interrupt is triggered where code execution is
/// resumed.
pub fn wait_for_vblank(&self) {
crate::syscall::wait_for_vblank();
}
}
let last_waited_number = self.last_waited_number.get();
self.last_waited_number.set(NUM_VBLANKS.read() + 1);
impl Drop for VBlank {
fn drop(&mut self) {
interrupt_to_root(Interrupt::VBlank).reduce();
if last_waited_number < NUM_VBLANKS.read() {
return;
}
crate::syscall::wait_for_vblank();
}
}