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Check if all addresses are writable before doing the actual writes

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Ry 2022-10-10 17:26:40 -07:00
parent 6fb6d07431
commit bfc0ae96d1
1 changed files with 22 additions and 0 deletions
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22
src/memory.rs
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@ -267,11 +267,33 @@ impl Memory {
} }
} }
pub fn write_16(&mut self, address: u32, half: u16) -> Option<()> { pub fn write_16(&mut self, address: u32, half: u16) -> Option<()> {
// first check if we can write to all addresses without faulting
if *self.mmu_enabled() {
let (_, writable_0) = self.virtual_to_physical(address).unwrap_or_else(|| (0, false));
let (_, writable_1) = self.virtual_to_physical(address + 1).unwrap_or_else(|| (0, false));
if !writable_0 { self.exception_sender().send(Exception::PageFaultWrite(address)).unwrap(); return None }
if !writable_1 { self.exception_sender().send(Exception::PageFaultWrite(address + 1)).unwrap(); return None }
}
// then do the actual writes
self.write_8(address, (half & 0x00FF) as u8)?; self.write_8(address, (half & 0x00FF) as u8)?;
self.write_8(address + 1, (half >> 8) as u8)?; self.write_8(address + 1, (half >> 8) as u8)?;
Some(()) Some(())
} }
pub fn write_32(&mut self, address: u32, word: u32) -> Option<()> { pub fn write_32(&mut self, address: u32, word: u32) -> Option<()> {
// first check if we can write to all addresses without faulting
if *self.mmu_enabled() {
let (_, writable_0) = self.virtual_to_physical(address).unwrap_or_else(|| (0, false));
let (_, writable_1) = self.virtual_to_physical(address + 1).unwrap_or_else(|| (0, false));
let (_, writable_2) = self.virtual_to_physical(address + 2).unwrap_or_else(|| (0, false));
let (_, writable_3) = self.virtual_to_physical(address + 3).unwrap_or_else(|| (0, false));
if !writable_0 { self.exception_sender().send(Exception::PageFaultWrite(address)).unwrap(); return None }
if !writable_1 { self.exception_sender().send(Exception::PageFaultWrite(address + 1)).unwrap(); return None }
if !writable_2 { self.exception_sender().send(Exception::PageFaultWrite(address + 2)).unwrap(); return None }
if !writable_3 { self.exception_sender().send(Exception::PageFaultWrite(address + 3)).unwrap(); return None }
}
// then do the actual writes
self.write_8(address, (word & 0x000000FF) as u8)?; self.write_8(address, (word & 0x000000FF) as u8)?;
self.write_8(address + 1, ((word & 0x0000FF00) >> 8) as u8)?; self.write_8(address + 1, ((word & 0x0000FF00) >> 8) as u8)?;
self.write_8(address + 2, ((word & 0x00FF0000) >> 16) as u8)?; self.write_8(address + 2, ((word & 0x00FF0000) >> 16) as u8)?;