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//! # `itm`
//!
//! A decoder for the ITM and DWT packet protocol as specifed in the
//! [ARMv7-M architecture reference manual, Appendix
//! D4](https://developer.arm.com/documentation/ddi0403/ed/). Any
//! references in this code base refers to this document.
//!
//! Aside from covering the entirety of the protocol, this crate offers
//! two iterators which reads data from the given [`Read`](std::io::Read)
//! instance:
//!
//! - [`Singles`](Singles), which decodes each packet in the stream in sequence,
//! yielding [`TracePacket`](TracePacket)s.
//!
//! - [`Timestamps`](Timestamps), which continuously decodes packets
//! from the stream until a local timestamp is encountered, yielding a
//! [`TimestampedTracePackets`](TimestampedTracePackets), which contains
//! [a timestamp relative to target reset of when the packets where
//! generated target-side](TimestampedTracePackets::timestamp).
//!
//! Usage is simple:
//! ```
//! use itm::{Decoder, DecoderOptions};
//!
//! // or a std::fs::File, or anything else that implements std::io::Read
//! let stream: &[u8] = &[
//! // ...
//! ];
//! let mut decoder = Decoder::<&[u8]>::new(stream, DecoderOptions { ignore_eof: false });
//! for packet in decoder.singles() {
//! // ...
//! }
//! ```
#[deny(rustdoc::broken_intra_doc_links)]
mod iter;
pub use iter::{
LocalTimestampOptions, Singles, Timestamp, TimestampedTracePackets, Timestamps,
TimestampsConfiguration,
};
#[cfg(feature = "serial")]
pub mod serial;
pub mod cortex_m;
use cortex_m::VectActive;
use std::convert::TryInto;
use std::io::Read;
use bitmatch::bitmatch;
use bitvec::prelude::*;
/// The set of valid packet types that can be decoded.
#[derive(Debug, Clone, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum TracePacket {
// Synchronization packet category (Appendix D4, p. 782)
/// A synchronization packet is a unique pattern in the bitstream.
/// It is identified and used to provide the alignment of other
/// packet bytes in the bitstream. (Appendix D4.2.1)
Sync,
// Protocol packet category (Appendix D4, p. 782)
/// Found in the bitstream if
///
/// - Software has written to an ITM stimulus port register when the
/// stimulus port output buffer is full.
/// - The DWT attempts to generate a hardware source packet when the
/// DWT output buffer is full.
/// - The local timestamp counter overflows.
///
/// See (Appendix D4.2.3).
Overflow,
/// A delta timestamp that measures the interval since the
/// generation of the last local timestamp and its relation to the
/// corresponding ITM/DWT data packets. (Appendix D4.2.4)
LocalTimestamp1 {
/// Timestamp value.
ts: u32,
/// Indicates the relationship between the generation of `ts`
/// and the corresponding ITM or DWT data packet.
data_relation: TimestampDataRelation,
},
/// A derivative of `LocalTimestamp1` for timestamp values between
/// 1-6. Always synchronous to te associated ITM/DWT data. (Appendix D4.2.4)
LocalTimestamp2 {
/// Timestamp value.
ts: u8,
},
/// An absolute timestamp based on the global timestamp clock that
/// contain the timestamp's lower-order bits. (Appendix D4.2.5)
GlobalTimestamp1 {
/// Lower-order bits of the timestamp; bits\[25:0\].
ts: u64,
/// Set if higher order bits output by the last GTS2 have
/// changed.
wrap: bool,
/// Set if the system has asserted a clock change input to the
/// processor since the last generated global timestamp.
clkch: bool,
},
/// An absolute timestamp based on the global timestamp clock that
/// contain the timestamp's higher-order bits. (Appendix D4.2.5)
GlobalTimestamp2 {
/// Higher-order bits of the timestamp value; bits\[63:26\] or
/// bits\[47:26\] depending on implementation.
ts: u64,
},
/// A packet that provides additional information about the
/// identified source (one of two possible, theoretically). On
/// ARMv7-M this packet is only used to denote on which ITM stimulus
/// port a payload was written. (Appendix D4.2.6)
Extension {
/// Source port page number.
page: u8,
},
// Source packet category
/// Contains the payload written to the ITM stimulus ports.
Instrumentation {
/// Stimulus port number.
port: u8,
/// Instrumentation data written to the stimulus port. MSB, BE.
payload: Vec<u8>,
},
/// One or more event counters have wrapped. (Appendix D4.3.1)
EventCounterWrap {
/// POSTCNT wrap (see Appendix C1, p. 732).
cyc: bool,
/// FOLDCNT wrap (see Appendix C1, p. 734).
fold: bool,
/// LSUCNT wrap (see Appendix C1, p. 734).
lsu: bool,
/// SLEEPCNT wrap (see Appendix C1, p. 734).
sleep: bool,
/// EXCCNT wrap (see Appendix C1, p. 734).
exc: bool,
/// CPICNT wrap (see Appendix C1, p. 734).
cpi: bool,
},
/// The processor has entered, exit, or returned to an exception.
/// (Appendix D4.3.2)
ExceptionTrace {
exception: VectActive,
action: ExceptionAction,
},
/// Periodic PC sample. (Appendix D4.3.3)
PCSample {
/// The value of the PC. `None` if periodic PC sleep packet.
pc: Option<u32>,
},
/// A DWT comparator matched a PC value. (Appendix D4.3.4)
DataTracePC {
/// The comparator number that generated the data.
comparator: u8,
/// The PC value for the instruction that caused the successful
/// address comparison.
pc: u32,
},
/// A DWT comparator matched an address. (Appendix D4.3.4)
DataTraceAddress {
/// The comparator number that generated the data.
comparator: u8,
/// Data address content; bits\[15:0\]. MSB, BE.
data: Vec<u8>,
},
/// A data trace packet with a value. (Appendix D4.3.4)
DataTraceValue {
/// The comparator number that generated the data.
comparator: u8,
/// Whether the data was read or written.
access_type: MemoryAccessType,
/// The data value. MSB, BE.
value: Vec<u8>,
},
}
/// Denotes the action taken by the processor by a given exception. (Table D4-6)
#[derive(Debug, Clone, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum ExceptionAction {
/// Exception was entered.
Entered,
/// Exception was exited.
Exited,
/// Exception was returned to.
Returned,
}
/// Denotes the type of memory access.
#[derive(Debug, Clone, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum MemoryAccessType {
/// Memory was read.
Read,
/// Memory was written.
Write,
}
/// Indicates the relationship between the generation of the local
/// timestamp packet and the corresponding ITM or DWT data packet.
/// (Appendix D4.2.4)
#[derive(Debug, Clone, PartialEq)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum TimestampDataRelation {
/// The local timestamp value is synchronous to the corresponding
/// ITM or DWT data. The value in the TS field is the timestamp
/// counter value when the ITM or DWT packet is generated.
Sync,
/// The local timestamp value is delayed relative to the ITM or DWT
/// data. The value in the TS field is the timestamp counter value
/// when the Local timestamp packet is generated.
///
/// Note: the local timestamp value corresponding to the previous
/// ITM or DWT packet is unknown, but must be between the previous
/// and the current local timestamp values.
UnknownDelay,
/// Output of the ITM or DWT packet corresponding to this Local
/// timestamp packet is delayed relative to the associated event.
/// The value in the TS field is the timestamp counter value when
/// the ITM or DWT packets is generated.
///
/// This encoding indicates that the ITM or DWT packet was delayed
/// relative to other trace output packets.
AssocEventDelay,
/// Output of the ITM or DWT packet corresponding to this Local
/// timestamp packet is delayed relative to the associated event,
/// and this Local timestamp packet is delayed relative to the ITM
/// or DWT data. This is a combined condition of `UnknownDelay` and
/// `AssocEventDelay`.
UnknownAssocEventDelay,
}
/// Set of malformed [`TracePacket`](TracePacket)s that can occur during decode.
#[derive(Debug, Clone, PartialEq, thiserror::Error)]
#[cfg_attr(feature = "serde", derive(serde::Serialize, serde::Deserialize))]
pub enum MalformedPacket {
/// Header is invalid and cannot be decoded.
#[error("Header is invalid and cannot be decoded: {}", format!("{:#b}", .0))]
InvalidHeader(u8),
/// The type discriminator ID in the hardware source packet header
/// is invalid or the associated payload is of wrong size.
#[error("Hardware source packet type discriminator ID ({disc_id}) or payload length ({}) is invalid", .payload.len())]
InvalidHardwarePacket {
/// The discriminator ID. Potentially invalid.
disc_id: u8,
/// Associated payload. Potentially invalid length. MSB, BE.
payload: Vec<u8>,
},
/// The type discriminator ID in the hardware source packet header
/// is invalid.
#[error("Hardware source packet discriminator ID is invalid: {disc_id}")]
InvalidHardwareDisc {
/// The discriminator ID. Potentially invalid.
disc_id: u8,
/// Associated payload length.
size: usize,
},
/// An exception trace packet refers to an invalid action or an
/// invalid exception number.
#[error("IRQ number {exception} and/or action {function} is invalid")]
InvalidExceptionTrace {
/// The exception number.
exception: u16,
/// Numerical representation of the function associated with the
/// exception number.
function: u8,
},
/// The payload length of a PCSample packet is invalid.
#[error("Payload length of PC sample is invalid: {}", .payload.len())]
InvalidPCSampleSize {
/// The payload constituting the PC value, of invalid size. MSB, BE.
payload: Vec<u8>,
},
/// The GlobalTimestamp2 packet does not contain a 48-bit or 64-bit
/// timestamp.
#[error("GlobalTimestamp2 packet does not contain a 48-bit or 64-bit timestamp")]
InvalidGTS2Size {
/// The payload constituting the timestamp, of invalid size. MSB, BE.
payload: Vec<u8>,
},
/// The number of zeroes in the Synchronization packet is less than
/// 47.
#[error(
"The number of zeroes in the Synchronization packet is less than expected: {0} < {}",
SYNC_MIN_ZEROS
)]
InvalidSync(usize),
/// A source packet (from software or hardware) contains an invalid
/// expected payload size.
#[error(
"A source packet (from software or hardware) contains an invalid expected payload size"
)]
InvalidSourcePayload {
/// The header which contains the invalid payload size.
header: u8,
/// The invalid payload size. See (Appendix D4.2.8, Table D4-4).
size: u8,
},
}
const SYNC_MIN_ZEROS: usize = 47;
/// The decoder's possible states. The default decoder state is `Header`
/// and will always return there after a maximum of two steps. (E.g. if
/// the current state is `Syncing` or `HardwareSource`, the next state
/// is `Header` again.)
enum PacketStub {
/// Next zero bits will be assumed to be part of a a Synchronization
/// packet until a set bit is encountered.
Sync(usize),
/// Next bytes will be assumed to be part of an Instrumentation
/// packet, until `payload` contains `expected_size` bytes.
Instrumentation { port: u8, expected_size: usize },
/// Next bytes will be assumed to be part of a Hardware source
/// packet, until `payload` contains `expected_size` bytes.
HardwareSource { disc_id: u8, expected_size: usize },
/// Next bytes will be assumed to be part of a LocalTimestamp{1,2}
/// packet, until the MSB is set.
LocalTimestamp {
data_relation: TimestampDataRelation,
},
/// Next bytes will be assumed to be part of a GlobalTimestamp1
/// packet, until the MSB is set.
GlobalTimestamp1,
/// Next bytes will be assumed to be part of a GlobalTimestamp2
/// packet, until the MSB is set.
GlobalTimestamp2,
}
enum HeaderVariant {
Packet(TracePacket),
Stub(PacketStub),
}
/// [`Decoder`](Decoder) configuration.
pub struct DecoderOptions {
/// Whether to keep reading after a (temporary) EOF condition. If
/// set iteration is done over [`Singles`](Singles) or
/// [`Timestamps`](Timestamps), [`next`](Iterator::next) will never
/// return unless the EOF condition is eventually resolved.
pub ignore_eof: bool,
}
#[derive(Debug, thiserror::Error)]
enum DecoderErrorInt {
#[error("Buffer failed to read from source: {0}")]
Io(#[from] std::io::Error),
#[error("EOF encountered")]
Eof,
#[error("untars")]
MalformedPacket(#[from] MalformedPacket),
}
/// Set of errors that can occur during decode.
#[derive(Debug, thiserror::Error)]
pub enum DecoderError {
#[error("I/O error: {0}")]
Io(#[from] std::io::Error),
#[error("A malformed packet was encountered: {0}")]
MalformedPacket(#[from] MalformedPacket),
}
struct Buffer<R>
where
R: Read,
{
reader: R,
buffer: BitVec,
ignore_eof: bool,
}
impl<R> Buffer<R>
where
R: Read,
{
pub fn new(reader: R, ignore_eof: bool) -> Buffer<R> {
Buffer {
reader,
ignore_eof,
buffer: BitVec::new(),
}
}
/// Tries to read up to 32 bytes from [Self::reader]. Continuously retries if [ignore_eof] is set.
fn buffer_some(&mut self) -> Result<(), DecoderErrorInt> {
// `Read::read` reportedly reads in 32-byte chunks. Source:
// <https://github.com/rust-embedded/itm/blob/3e4251b42aa2e4b05ae372c47c7b835b8acae6dc/src/lib.rs#L42>.
let mut buffer: [u8; 32] = [0; 32];
loop {
match self.reader.read(&mut buffer) {
Ok(0) => {
if self.ignore_eof {
continue;
}
return Err(DecoderErrorInt::Eof);
}
Ok(n) => {
let mut bv = BitVec::<_, LocalBits>::from_vec(buffer[0..n].to_vec());
bv.reverse();
bv.append(&mut self.buffer);
self.buffer.append(&mut bv);
return Ok(());
}
Err(e) => {
// XXX any other errors we should retry on?
if e.kind() == std::io::ErrorKind::Interrupted {
continue;
}
return Err(e.into());
}
}
}
}
/// Pops a single bit from the buffer. Tries to buffer first if
/// the buffer is empty.
pub fn pop_bit(&mut self) -> Result<bool, DecoderErrorInt> {
loop {
match self.buffer.pop() {
None => {
self.buffer_some()?;
continue;
}
Some(bit) => return Ok(bit),
}
}
}
/// Pops a single byte from the buffer. Tries to buffer if more data
/// is needed.
pub fn pop_byte(&mut self) -> Result<u8, DecoderErrorInt> {
let mut b: u8 = 0;
for i in 0..8 {
b |= (self.pop_bit()? as u8) << i;
}
Ok(b)
}
/// Pops `cnt` bytes from the buffer. Tries to buffer if more data
/// is needed.
pub fn pop_bytes(&mut self, cnt: usize) -> Result<Vec<u8>, DecoderErrorInt> {
let mut bytes = vec![];
for _ in 0..cnt {
bytes.push(self.pop_byte()?);
}
Ok(bytes)
}
/// Pops bytes from the incoming buffer until the continuation-bit
/// is not set. All [TracePacket]s with a defined payload follow
/// this payload schema. (c.f. e.g. Appendix D4, Fig. D4-4)
#[bitmatch]
pub fn pop_payload(&mut self) -> Result<Vec<u8>, DecoderErrorInt> {
let mut payload = vec![];
loop {
let b = self.pop_byte()?;
payload.push(b);
#[bitmatch]
let "c???_????" = b;
if c == 0 {
break;
}
}
Ok(payload)
}
}
/// ITM/DWT packet protocol decoder.
pub struct Decoder<R>
where
R: Read,
{
/// Intermediate buffer to store the trace byte stream read from the
/// given [Read] instance.
buffer: Buffer<R>,
/// Whether the decoder is in a state of synchronization.
sync: Option<usize>,
}
impl<R> Decoder<R>
where
R: Read,
{
pub fn new(reader: R, options: DecoderOptions) -> Decoder<R> {
Decoder {
buffer: Buffer::new(reader, options.ignore_eof),
sync: None,
}
}
/// Returns a reference to the underlying [`Read`](Read).
pub fn get_ref(&self) -> &R {
&self.buffer.reader
}
/// Returns a mutable reference to the underlying [`Read`](Read).
pub fn get_mut(&mut self) -> &mut R {
&mut self.buffer.reader
}
/// Returns an iterator over [`TracePacket`](TracePacket)s. Consumes
/// the [`Decoder`](Decoder).
pub fn singles(self) -> Singles<R> {
Singles::new(self)
}
/// Returns an iterator over
/// [`TimestampedTracePackets`](TimestampedTracePackets). Consumes
/// the [`Decoder`](Decoder).
///
/// # Panics
///
/// This iterator constuctor will panic if
/// [`options.lts_prescaler`](TimestampsConfiguration::lts_prescaler)
/// is [`Disabled`](LocalTimestampOptions::Disabled).
pub fn timestamps(self, options: TimestampsConfiguration) -> Timestamps<R> {
Timestamps::new(self, options)
}
/// Returns the next [TracePacket] in the stream.
fn next_single(&mut self) -> Result<TracePacket, DecoderErrorInt> {
if self.sync.is_some() {
return self.handle_sync();
}
assert!(self.sync.is_none());
match decode_header(self.buffer.pop_byte()?)? {
HeaderVariant::Packet(p) => Ok(p),
HeaderVariant::Stub(s) => self.process_stub(&s),
}
}
/// Read zeros from the bitstream until the first bit is set. This
/// realigns the incoming bitstream for further processing, which
/// broke alignment on target-generated overflow packet.
fn handle_sync(&mut self) -> Result<TracePacket, DecoderErrorInt> {
let zeros = self.sync.unwrap();
match (self.buffer.pop_bit()?, zeros) {
(true, zeros) if zeros >= SYNC_MIN_ZEROS => {
self.sync = None;
Ok(TracePacket::Sync)
}
(true, zeros) if zeros < SYNC_MIN_ZEROS => {
self.sync = None;
Err(MalformedPacket::InvalidSync(zeros).into())
}
(false, _) => {
*self.sync.as_mut().unwrap() += 1;
self.handle_sync()
}
(true, _) => unreachable!(),
}
}
#[bitmatch]
fn process_stub(&mut self, stub: &PacketStub) -> Result<TracePacket, DecoderErrorInt> {
match stub {
PacketStub::Sync(count) => {
self.sync = Some(*count);
self.handle_sync()
}
PacketStub::HardwareSource {
disc_id,
expected_size,
} => {
let payload = self.buffer.pop_bytes(*expected_size)?;
handle_hardware_source(*disc_id, payload).map_err(DecoderErrorInt::MalformedPacket)
}
PacketStub::LocalTimestamp { data_relation } => {
let payload = self.buffer.pop_payload()?;
Ok(TracePacket::LocalTimestamp1 {
data_relation: data_relation.clone(),
// MAGIC(27): c.f. Appendix D4.2.4
ts: extract_timestamp(payload, 27) as u32,
})
}
PacketStub::GlobalTimestamp1 => {
let payload = self.buffer.pop_payload()?;
#[bitmatch]
let "?wc?_????" = payload.last().unwrap();
Ok(TracePacket::GlobalTimestamp1 {
clkch: c > 0,
wrap: w > 0,
// MAGIC(25): c.f. Appendix D4.2.5
ts: extract_timestamp(payload, 25),
})
}
PacketStub::GlobalTimestamp2 => {
let payload = self.buffer.pop_payload()?;
Ok(TracePacket::GlobalTimestamp2 {
ts: extract_timestamp(
payload.to_vec(),
match payload.len() {
4 => 47 - 26, // 48 bit timestamp
6 => 63 - 26, // 64 bit timestamp
_ => {
return Err(DecoderErrorInt::MalformedPacket(
MalformedPacket::InvalidGTS2Size {
payload: payload.to_vec(),
},
))
}
},
),
})
}
PacketStub::Instrumentation {
port,
expected_size,
} => {
let payload = self.buffer.pop_bytes(*expected_size)?;
Ok(TracePacket::Instrumentation {
port: *port,
payload,
})
}
}
}
}
// TODO template this for u32, u64?
fn extract_timestamp(payload: Vec<u8>, max_len: u64) -> u64 {
// Decode the first N - 1 payload bytes
let (rtail, head) = payload.split_at(payload.len() - 1);
let mut ts: u64 = 0;
for (i, b) in rtail.iter().enumerate() {
ts |= ((b & !(1 << 7)) as u64) // mask out continuation bit
<< (7 * i);
}
// Mask out the timestamp's MSBs and shift them into the final
// value.
let shift = 7 - (max_len % 7);
let mask: u8 = 0xFFu8.wrapping_shl(shift.try_into().unwrap()) >> shift;
ts | (((head[0] & mask) as u64) << (7 * rtail.len()))
}
/// Decodes the first byte of a packet, the header, into a complete packet or a packet stub.
#[allow(clippy::bad_bit_mask)]
#[bitmatch]
fn decode_header(header: u8) -> Result<HeaderVariant, MalformedPacket> {
fn translate_ss(ss: u8) -> Option<usize> {
// See (Appendix D4.2.8, Table D4-4)
Some(
match ss {
0b01 => 2,
0b10 => 3,
0b11 => 5,
_ => return None,
} - 1, // ss would include the header byte, but it has already been processed
)
}
let stub = |s| Ok(HeaderVariant::Stub(s));
let packet = |p| Ok(HeaderVariant::Packet(p));
#[bitmatch]
match header {
// Synchronization packet category
"0000_0000" => stub(PacketStub::Sync(8)),
// Protocol packet category
"0111_0000" => packet(TracePacket::Overflow),
"11rr_0000" => {
// Local timestamp, format 1 (LTS1)
let tc = r; // relationship with corresponding data
stub(PacketStub::LocalTimestamp {
data_relation: match tc {
0b00 => TimestampDataRelation::Sync,
0b01 => TimestampDataRelation::UnknownDelay,
0b10 => TimestampDataRelation::AssocEventDelay,
0b11 => TimestampDataRelation::UnknownAssocEventDelay,
_ => unreachable!(),
},
})
}
"0ttt_0000" => {
// Local timestamp, format 2 (LTS2)
packet(TracePacket::LocalTimestamp2 { ts: t })
}
"1001_0100" => {
// Global timestamp, format 1 (GTS1)
stub(PacketStub::GlobalTimestamp1)
}
"1011_0100" => {
// Global timestamp, format 2(GTS2)
stub(PacketStub::GlobalTimestamp2)
}
"0ppp_1000" => {
// Extension packet
packet(TracePacket::Extension { page: p })
}
// Source packet category
"aaaa_a0ss" => {
// Instrumentation packet
stub(PacketStub::Instrumentation {
port: a,
expected_size: if let Some(s) = translate_ss(s) {
s
} else {
return Err(MalformedPacket::InvalidSourcePayload { header, size: s });
},
})
}
"aaaa_a1ss" => {
// Hardware source packet
let disc_id = a;
if !(0..=2).contains(&disc_id) && !(8..=23).contains(&disc_id) {
return Err(MalformedPacket::InvalidHardwareDisc {
disc_id,
size: s.into(),
});
}
stub(PacketStub::HardwareSource {
disc_id,
expected_size: if let Some(s) = translate_ss(s) {
s
} else {
return Err(MalformedPacket::InvalidSourcePayload { header, size: s });
},
})
}
#[allow(clippy::identity_op)]
"hhhh_hhhh" => Err(MalformedPacket::InvalidHeader(h)),
}
}
/// Decodes the payload of a hardware source packet.
#[bitmatch]
fn handle_hardware_source(disc_id: u8, payload: Vec<u8>) -> Result<TracePacket, MalformedPacket> {
match disc_id {
0 => {
// event counter wrap
if payload.len() != 1 {
return Err(MalformedPacket::InvalidHardwarePacket { disc_id, payload });
}
#[bitmatch]
let "??yf_lsec" = payload[0];
Ok(TracePacket::EventCounterWrap {
cyc: y != 0,
fold: f != 0,
lsu: l != 0,
sleep: s != 0,
exc: e != 0,
cpi: c != 0,
})
}
1 => {
// exception trace
if payload.len() != 2 {
return Err(MalformedPacket::InvalidHardwarePacket { disc_id, payload });
}
#[bitmatch]
let "??ff_???e" = payload[1];
let exception_number = ((e as u16) << 8) | payload[0] as u16;
Ok(TracePacket::ExceptionTrace {
exception: if let Some(exception) = VectActive::from(exception_number) {
exception
} else {
return Err(MalformedPacket::InvalidExceptionTrace {
exception: exception_number,
function: f,
});
},
action: match f {
0b01 => ExceptionAction::Entered,
0b10 => ExceptionAction::Exited,
0b11 => ExceptionAction::Returned,
_ => {
return Err(MalformedPacket::InvalidExceptionTrace {
exception: exception_number,
function: f,
})
}
},
})
}
2 => {
// PC sample
match payload.len() {
1 if payload[0] == 0 => Ok(TracePacket::PCSample { pc: None }),
4 => Ok(TracePacket::PCSample {
pc: Some(u32::from_le_bytes(payload.try_into().unwrap())),
}),
_ => Err(MalformedPacket::InvalidPCSampleSize { payload }),
}
}
8..=23 => {
// data trace
#[bitmatch]
let "???t_tccd" = disc_id; // we have already masked out bit[2:0]
let comparator = c;
match (t, d, payload.len()) {
(0b01, 0, 4) => {
// PC value packet
Ok(TracePacket::DataTracePC {
comparator,
pc: u32::from_le_bytes(payload.try_into().unwrap()),
})
}
(0b01, 1, 2) => {
// address packet
Ok(TracePacket::DataTraceAddress {
comparator,
data: payload,
})
}
(0b10, d, _) => {
// data value packet
Ok(TracePacket::DataTraceValue {
comparator,
access_type: if d == 0 {
MemoryAccessType::Read
} else {
MemoryAccessType::Write
},
value: payload,
})
}
_ => Err(MalformedPacket::InvalidHardwarePacket { disc_id, payload }),
}
}
_ => unreachable!(), // we already verify the discriminator when we decode the header
}
}
#[cfg(test)]
mod decoder_buffer_utils {
use super::*;
#[test]
fn buffer_pop_bytes() {
let bytes: &[u8] = &[0b1000_0000, 0b1010_0000, 0b1000_0100, 0b0110_0000];
let mut decoder = Decoder::new(bytes, DecoderOptions { ignore_eof: false });
assert_eq!(decoder.buffer.pop_bytes(3).unwrap().len(), 3);
}
#[test]
fn buffer_pop_payload() {
#[rustfmt::skip]
let payload: &[u8] = &[
0b1000_0000,
0b1010_0000,
0b1000_0100,
0b0110_0000
];
let mut decoder = Decoder::new(payload, DecoderOptions { ignore_eof: false });
assert_eq!(decoder.buffer.pop_payload().unwrap(), payload);
}
#[test]
fn extract_timestamp() {
#[rustfmt::skip]
let ts: Vec<u8> = [
0b1000_0000,
0b1000_0000,
0b1000_0000,
0b0000_0000,
].to_vec();
assert_eq!(super::extract_timestamp(ts, 25), 0);
#[rustfmt::skip]
let ts: Vec<u8> = [
0b1000_0001,
0b1000_0111,
0b1001_1111,
0b0111_1111
].to_vec();
assert_eq!(
super::extract_timestamp(ts, 27),
0b1111111_0011111_0000111_0000001,
);
#[rustfmt::skip]
let ts: Vec<u8> = [
0b1000_0001,
0b1000_0111,
0b1001_1111,
0b1111_1111
].to_vec();
assert_eq!(
super::extract_timestamp(ts, 25),
0b11111_0011111_0000111_0000001,
);
}
}