From 1a3495bf07be31e7b6767d4b86d05ff755e012d3 Mon Sep 17 00:00:00 2001
From: German <germangolozubow@gmail.com>
Date: Mon, 21 Oct 2024 01:26:48 +0300
Subject: [PATCH] TryFrom implementation for ExceptionVector

---
 src/structures/idt.rs | 81 +++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)

diff --git a/src/structures/idt.rs b/src/structures/idt.rs
index 4a92bacf..7d0431e4 100644
--- a/src/structures/idt.rs
+++ b/src/structures/idt.rs
@@ -24,7 +24,9 @@ use crate::registers::rflags::RFlags;
 use crate::{PrivilegeLevel, VirtAddr};
 use bit_field::BitField;
 use bitflags::bitflags;
+use core::convert::TryFrom;
 use core::fmt;
+use core::fmt::Formatter;
 use core::marker::PhantomData;
 use core::ops::Bound::{Excluded, Included, Unbounded};
 use core::ops::{
@@ -1328,6 +1330,85 @@ pub enum ExceptionVector {
     Security = 0x1E,
 }
 
+/// Exception vector number is invalid
+///
+/// Explains the reason an exception vector number is considered invalid
+#[derive(Debug)]
+pub enum InvalidExceptionVectorNumber {
+    /// Coprocessor Segment Overrun exception handled as part of the General Protection Fault
+    IsCoprocessorSegmentOverrun(u8),
+    /// Reserved
+    Reserved(u8),
+    /// Only the first 32 numbers can be exception numbers
+    NotException(u8),
+}
+
+impl fmt::Display for InvalidExceptionVectorNumber {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        match self {
+            InvalidExceptionVectorNumber::IsCoprocessorSegmentOverrun(exception_vector_number) => {
+                write!(f, "{exception_vector_number} cannot be a valid exception vector number because the Coprocessor Segment Overrun exception is handled as part of the General Protection Fault")
+            }
+            InvalidExceptionVectorNumber::Reserved(exception_vector_number) => {
+                write!(f, "{exception_vector_number} cannot be a valid exception vector number because it is reserved")
+            }
+            InvalidExceptionVectorNumber::NotException(exception_vector_number) => {
+                write!(f, "{exception_vector_number} cannot be a valid exception vector number because only the first 32 numbers can be exception numbers")
+            }
+        }
+    }
+}
+
+impl TryFrom<u8> for ExceptionVector {
+    type Error = InvalidExceptionVectorNumber;
+
+    /// Tries to convert the exception vector number to [`ExceptionVector`]
+    ///
+    /// Fails if exception vector number is Coprocessor Segment Overrun, reserved or not exception vector number
+    fn try_from(exception_vector_number: u8) -> Result<Self, Self::Error> {
+        match exception_vector_number {
+            0x00 => Ok(Self::Division),
+            0x01 => Ok(Self::Debug),
+            0x02 => Ok(Self::NonMaskableInterrupt),
+            0x03 => Ok(Self::Breakpoint),
+            0x04 => Ok(Self::Overflow),
+            0x05 => Ok(Self::BoundRange),
+            0x06 => Ok(Self::InvalidOpcode),
+            0x07 => Ok(Self::DeviceNotAvailable),
+            0x08 => Ok(Self::Double),
+            0x09 => Err(InvalidExceptionVectorNumber::IsCoprocessorSegmentOverrun(
+                exception_vector_number,
+            )),
+            0x0A => Ok(Self::InvalidTss),
+            0x0B => Ok(Self::SegmentNotPresent),
+            0x0C => Ok(Self::Stack),
+            0x0D => Ok(Self::GeneralProtection),
+            0x0E => Ok(Self::Page),
+            0x0F => Err(InvalidExceptionVectorNumber::Reserved(
+                exception_vector_number,
+            )),
+            0x10 => Ok(Self::X87FloatingPoint),
+            0x11 => Ok(Self::AlignmentCheck),
+            0x12 => Ok(Self::MachineCheck),
+            0x13 => Ok(Self::SimdFloatingPoint),
+            0x14 => Ok(Self::Virtualization),
+            0x15 => Ok(Self::ControlProtection),
+            0x16..=0x1B => Err(InvalidExceptionVectorNumber::Reserved(
+                exception_vector_number,
+            )),
+            0x1C => Ok(Self::HypervisorInjection),
+            0x1D => Ok(Self::VmmCommunication),
+            0x1E => Ok(Self::Security),
+            0x1F => Err(InvalidExceptionVectorNumber::Reserved(
+                exception_vector_number,
+            )),
+            0x20..=u8::MAX => Err(InvalidExceptionVectorNumber::NotException(
+                exception_vector_number,
+            )),
+        }
+    }
+}
+
 #[cfg(all(
     feature = "instructions",
     feature = "abi_x86_interrupt",