Merge #88

88: make compilable on stable r=japaric a=japaric

This PR makes this crate compilable on stable when the "inline-asm" and "singleton" Cargo features
are disabled (they are enabled by default to maintain backwards compatibility).

The main change has been replacing almost (\*) all inline `asm!` invocations with FFI calls into
external assembly files.

(\*) Stuff that has not been converted into external assembly file and thus is not available on
stable:

- Reading the (A)PSR register (I'm not sure if this will work with the extra function call overhead)

- Reading and writing the Link Register (LR)

- Reading and writing the Program Counter (PC)

I would appreciate if someone checked that all the stuff that's now using FFI calls has the same
semantics as the inline `asm!` version.


Co-authored-by: Jorge Aparicio <jorge@japaric.io>

1 files changed, 0 insertions, 72 deletions

diff --git a/src/exception.rs b/src/exception.rs
deleted file mode 100644
index b40cf1b..0000000
--- a/src/exception.rs
+++ /dev/null
@@ -1,72 +0,0 @@
-//! 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,
-}