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exception.rs
exception.rs 1.95 KiB
//! Exceptions
/// Enumeration of all the exception types
#[derive(Clone, Copy, Debug, Eq, PartialEq)]
pub enum Exception {
/// Non-maskable interrupt
NMI,
/// Other type of faults and unhandled faults
HardFault,
/// Memory protection related fault
MenManage,
/// Pre-fetch or memory access fault
BusFault,
/// Fault due to undefined instruction or illegal state
UsageFault,
/// Supervisor call
SVCall,
/// Pendable request for system-level service
PendSV,
/// System timer exception
SysTick,
/// An interrupt
Interrupt(u8),
// Unreachable variant
#[doc(hidden)] Reserved,
}
impl Exception {
/// Returns the type of the exception that's currently active
///
/// Returns `None` if no exception is currently active
pub fn active() -> Option<Exception> {
// NOTE(safe) atomic read with no side effects
let icsr = unsafe { (*::peripheral::SCB::ptr()).icsr.read() };
Some(match icsr as u8 {
0 => return None,
2 => Exception::NMI,
3 => Exception::HardFault,
4 => Exception::MenManage,
5 => Exception::BusFault,
6 => Exception::UsageFault,
11 => Exception::SVCall,
14 => Exception::PendSV,
15 => Exception::SysTick,
n if n >= 16 => Exception::Interrupt(n - 16),
_ => Exception::Reserved,
})
}
}
/// Registers stacked (pushed into the stack) during an exception
#[derive(Clone, Copy, Debug)]
#[repr(C)]
pub struct ExceptionFrame {
/// (General purpose) Register 0
pub r0: u32,
/// (General purpose) Register 1
pub r1: u32,
/// (General purpose) Register 2
pub r2: u32,
/// (General purpose) Register 3
pub r3: u32,
/// (General purpose) Register 12
pub r12: u32,
/// Linker Register
pub lr: u32,
/// Program Counter
pub pc: u32,
/// Program Status Register
pub xpsr: u32,
}