fix tests and warnings

README.md

@@ -136,6 +136,29 @@ The same program can be written in a compact form:
 ((ld r0 100)(:again)(sub r0 1 (nz? (j :again))))
 ```
 
+### Includes
+
+Croissant allows program composition using includes.
+
+```
+(include path)
+```
+
+Path can be a filesystem absolute or relative path (with slashes). Relative path is always resolved from the current source file.
+Use double quotes if needed.
+
+If the included file is missing an extension, `.csn` is appended automatically.
+
+Each included file must contain a list of instructions or procedures, just like the main file.
+
+Includes work at the S-expression level. The included file is parsed to instructions and inserted
+in place of the include directive. Error reports will always show which file the line and column refer to.
+
+There are no special scoping rules. It is possible to define a label in a file and jump to it from another.
+Defines and register aliases (sym) also work cross-file. 
+
+Don't go too crazy with includes, it can get messy. Or do, I'm not your mom.
+
 ## Instruction
 
 Instructions are written like this:
@@ -187,7 +210,8 @@ The different ways to specify a value can be grouped as "reads" and "writes":
 - `RW` - intersection of the two sets, capable of reading and writing: `REG`, `SYM`, `@REG`, `@SYM`
 
 Objects (`@reg`, `@sym`) can be read or written as if they were a register, but only if the referenced object supports it.
-Other objects may produce a runtime fault or set the INVALID flag.
+Other objects may produce a runtime fault or set the INVALID flag. 
+The object syntax is also used to read values yielded by a generator-like coroutine.
 
 In the instruction lists below, I will use the symbols `Rd` for reads, `Wr` for writes, `RW` for read-writes, and `@Obj` for object handles,
 with optional description after an apostrophe, such as: `(add Wr'dst Rd'a Rd'b)`. 
@@ -325,6 +349,29 @@ You can also use one register for up to 64 mutexes.
 
 Remember to only use global registers (or buffer items) as mutexes: `g0`-`g15`. Each coroutine has its own set of *regular* registers.
 
+Another way to avoid race conditions is to use **critical sections**. 
+Context switch (switching between active coroutines) is forbidden in a critical section. Try to keep critical sections as short as possible,
+since they can distort sleep times and cause other similar problems.
+
+```
+(crit-begin)
+...
+(crit-end)
+```
+
+A safer way is to use the "critical block", which expands to the same, but also detects some common bugs at compile time,
+like trying to jump out of the critical section.
+
+```
+(crit
+    ...
+)
+```
+
+Critical section nesting is allowed, but probably a bug.
+
+**Beware deadlocks!**
+
 ### Using coroutines as generators
 
 A coroutine can "yield a value" by invoking the `yield` instruction with an operand. This can be done any number of times.
@@ -341,6 +388,11 @@ The coroutine is blocked until the value is consumed by someone. To consume a yi
 (ld r0 @r5) ; read a yielded value
 ```
 
+**Caution!!!** Due to the way this is implemented, the instruction that tries to use a yielded value might partially execute
+before detecting that it is blocked, and will be retried when the thread is next scheduled to run. This has the consequence
+that if something like a object handle is read by the same instruction, it may be read multiple times while waiting for the
+yielded value. It is recommended to *never combine reads of a yielded value with reads of other object handles*.
+
 ### Joining a coroutine
 
 Use the `join` instruction with a coroutine object handle to wait for its completion.
@@ -353,7 +405,7 @@ The returned values are placed in the result registers, just like with the `call
 (spawn r5 foo)
 ; ...
 
-(join @r0)
+(join @r5)
 ; res0-res15 now contain return values
 ```
 
@@ -379,6 +431,36 @@ to a varying number of skips and conditional instructions by the assembler. Only
 
 Jumping to a label is always safer than a manual skip.
 
+### Loop syntactic sugar
+
+Infinite loops are a very common construct, so there is special syntax added for them.
+
+These are converted by the assembler to an anonymous label and a jump to it.
+
+```
+(loop
+    ...ops
+)
+```
+
+If you want to have a convenient jump target, give the loop a name. This lets you easily "break" and "continue" 
+by jumping to the labels.
+
+```
+(loop :label
+    ...ops
+)
+```
+
+becomes
+
+```
+(:label)
+...ops
+(j :label)
+(:label-end)
+```
+
 ## Built-in Instructions
 
 ...and pseudo-instructions
@@ -473,9 +555,34 @@ Jumping to a label is always safer than a manual skip.
 ; The arguments are passed as argX. Return values are stored in resX registers.
 (call PROC Rd...)
 
-; Exit the current routine with return values
+; Spawn a coroutine. The handle is stored in the output register.
+(spawn Wr'handle PROC Rd...)
+
+; Exit the current routine (or coroutine) with return values
 (ret Rd...)
 
+; Yield control from a coroutine (use when waiting for a mutex to give control early to 
+; other coroutines that might be holding it)
+(yield)
+
+; Yield a value generated by a coroutine. Gives up control and blocks until the value is consumed.
+; Conversely, an instruction that tries to read a yielded value using the object handle is blocked
+; until such value becomes available.
+(yield Rd'value)
+
+; Wait for a coroutine to complete, read its return values and delete it.
+(join @Obj)
+
+; Begin a critical section (no context switch allowed)
+(crit-begin)
+; End a critical section
+(crit-end)
+
+; Shortcut to define a critical section
+(crit
+    ...ops
+)
+
 ; Generate a run-time fault with a debugger message
 (fault)
 (fault message)
@@ -491,6 +598,9 @@ Jumping to a label is always safer than a manual skip.
 ; The label can be a numeric or string label, its sole purpose is tying the two together. They must be unique in the program.
 (barrier-open LABEL)
 (barrier-close LABEL)
+
+; Set coroutine scheduler timeslice (in microseconds). Set to zero to disable preemption.
+(rt-opt RT_TIMESLICE Rd'usec)
 ```
 
 ## Arithmetic Module

crsn/crsn-sexp/src/error.rs

@@ -1,5 +1,6 @@
-use std::{cmp, fmt};
-use std::fmt::{Formatter, Debug};
+use std::{fmt};
+use super::SourcePosition;
+use position::get_line_and_column;
 
 /// The representation of an s-expression parse error.
 pub struct Error {
@@ -9,38 +10,6 @@ pub struct Error {
     pub pos: SourcePosition,
 }
 
-/// Position in the input string
-#[derive(PartialEq, Clone, Default)]
-pub struct SourcePosition {
-    /// The line number on which the error occurred.
-    pub line: u32,
-    /// The column number on which the error occurred.
-    pub column: u32,
-    /// The index in the given string which caused the error.
-    pub index: u32,
-}
-
-impl fmt::Display for SourcePosition {
-    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        write!(f, "{}:{}", self.line, self.column)
-    }
-}
-
-impl Debug for SourcePosition {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        if f.alternate() {
-            f.debug_struct("SourcePosition")
-                .field("line", &self.line)
-                .field("column", &self.column)
-                .field("index", &self.index)
-                .finish()
-        } else {
-            // shorter version
-            write!(f, "Pos({}:{})", self.line, self.column)
-        }
-    }
-}
-
 /// Since errors are the uncommon case, they're boxed. This keeps the size of
 /// structs down, which helps performance in the common case.
 ///
@@ -54,7 +23,7 @@ pub(crate) type ERes<T> = Result<T, Err>;
 
 impl fmt::Display for Error {
     fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
-        write!(f, "{}:{}: {}", self.pos.line, self.pos.column, self.message)
+        write!(f, "{}: {}", self.pos, self.message)
     }
 }
 
@@ -66,24 +35,6 @@ impl fmt::Debug for Error {
 
 impl std::error::Error for Error {}
 
-pub(crate) fn get_line_and_column(s: &str, pos: usize) -> SourcePosition {
-    let mut line: usize = 1;
-    let mut col: isize = -1;
-    for c in s.chars().take(pos + 1) {
-        if c == '\n' {
-            line += 1;
-            col = -1;
-        } else {
-            col += 1;
-        }
-    }
-    SourcePosition {
-        line: line as u32,
-        column: cmp::max(col, 0) as u32,
-        index: pos as u32,
-    }
-}
-
 #[cold]
 fn err_impl(message: &'static str, s: &str, pos: usize) -> Err {
     Box::new(Error {
@@ -96,12 +47,3 @@ fn err_impl(message: &'static str, s: &str, pos: usize) -> Err {
 pub(crate) fn err<T>(message: &'static str, s: &str, pos: usize) -> ERes<T> {
     Err(err_impl(message, s, pos))
 }
-
-/// Build a span
-pub(crate) fn spos(s: &str, pos: usize) -> SourcePosition {
-    if pos >= s.len() {
-        Default::default()
-    } else {
-        get_line_and_column(s, pos)
-    }
-}

crsn/crsn-sexp/src/lib.rs

@@ -8,14 +8,16 @@ use std::borrow::Cow;
 use std::fmt;
 use std::str::{self, FromStr};
 
-use error::{ERes, err, spos};
+use error::{ERes, err};
 pub use error::Error;
-pub use error::SourcePosition;
+pub use position::SourcePosition;
+use position::spos;
 
 #[cfg(test)]
 mod test;
 
 mod error;
+mod position;
 
 /// A single data element in an s-expression. Floats are excluded to ensure
 /// atoms may be used as keys in ordered and hashed data structures.

crsn/crsn-sexp/src/position.rs

@@ -0,0 +1,72 @@
+use std::{fmt, cmp};
+use std::fmt::{Formatter, Debug};
+
+/// Position in the input string
+#[derive(PartialEq, Clone, Default)]
+pub struct SourcePosition {
+    /// The line number on which the error occurred.
+    pub line: u32,
+    /// The column number on which the error occurred.
+    pub column: u32,
+    /// The index in the given string which caused the error.
+    pub index: u32,
+    /// File index if there are multiple files
+    pub file: u32,
+}
+
+impl fmt::Display for SourcePosition {
+    fn fmt(&self, f: &mut fmt::Formatter) -> Result<(), fmt::Error> {
+        write!(f, "{}:{}", self.line, self.column)
+    }
+}
+
+impl SourcePosition {
+    pub fn with_file(mut self, file: u32) -> Self {
+        self.file = file;
+        self
+    }
+}
+
+impl Debug for SourcePosition {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        if f.alternate() {
+            f.debug_struct("SourcePosition")
+                .field("line", &self.line)
+                .field("column", &self.column)
+                .field("index", &self.index)
+                .field("file", &self.file)
+                .finish()
+        } else {
+            // shorter version
+            write!(f, "Pos({}|{}:{})", self.file, self.line, self.column)
+        }
+    }
+}
+
+pub(crate) fn get_line_and_column(s: &str, pos: usize) -> SourcePosition {
+    let mut line: usize = 1;
+    let mut col: isize = -1;
+    for c in s.chars().take(pos + 1) {
+        if c == '\n' {
+            line += 1;
+            col = -1;
+        } else {
+            col += 1;
+        }
+    }
+    SourcePosition {
+        line: line as u32,
+        column: cmp::max(col, 0) as u32,
+        index: pos as u32,
+        file: 0
+    }
+}
+
+/// Build a span
+pub(crate) fn spos(s: &str, pos: usize) -> SourcePosition {
+    if pos >= s.len() {
+        Default::default()
+    } else {
+        get_line_and_column(s, pos)
+    }
+}

crsn/crsn-sexp/src/test.rs

@@ -1,5 +1,5 @@
 use super::*;
-use super::error::get_line_and_column;
+use super::position::get_line_and_column;
 
 #[test]
 fn test_hello_world() {
@@ -67,23 +67,23 @@ fn show_an_error() {
 #[test]
 fn line_and_col_test() {
     let s = "0123456789\n0123456789\n\n6";
-    assert_eq!(get_line_and_column(s, 4), SourcePosition { line: 1, column: 4, index: 4 });
+    assert_eq!(get_line_and_column(s, 4), SourcePosition { line: 1, column: 4, index: 4, file: 0 });
 
-    assert_eq!(get_line_and_column(s, 10), SourcePosition { line: 2, column: 0, index: 10 });
-    assert_eq!(get_line_and_column(s, 11), SourcePosition { line: 2, column: 0, index: 11 });
-    assert_eq!(get_line_and_column(s, 15), SourcePosition { line: 2, column: 4, index: 15 });
+    assert_eq!(get_line_and_column(s, 10), SourcePosition { line: 2, column: 0, index: 10, file: 0 });
+    assert_eq!(get_line_and_column(s, 11), SourcePosition { line: 2, column: 0, index: 11, file: 0 });
+    assert_eq!(get_line_and_column(s, 15), SourcePosition { line: 2, column: 4, index: 15, file: 0 });
 
-    assert_eq!(get_line_and_column(s, 21), SourcePosition { line: 3, column: 0, index: 21 });
-    assert_eq!(get_line_and_column(s, 22), SourcePosition { line: 4, column: 0, index: 22 });
-    assert_eq!(get_line_and_column(s, 23), SourcePosition { line: 4, column: 0, index: 23 });
-    assert_eq!(get_line_and_column(s, 500), SourcePosition { line: 4, column: 0, index: 500 });
+    assert_eq!(get_line_and_column(s, 21), SourcePosition { line: 3, column: 0, index: 21, file: 0 });
+    assert_eq!(get_line_and_column(s, 22), SourcePosition { line: 4, column: 0, index: 22, file: 0 });
+    assert_eq!(get_line_and_column(s, 23), SourcePosition { line: 4, column: 0, index: 23, file: 0 });
+    assert_eq!(get_line_and_column(s, 500), SourcePosition { line: 4, column: 0, index: 500, file: 0 });
 }
 
 #[test]
 fn sexp_size() {
     // I just want to see when this changes, in the diff.
     use std::mem;
-    assert_eq!(mem::size_of::<Sexp>(), mem::size_of::<isize>() * 6);
+    assert_eq!(mem::size_of::<Sexp>(), mem::size_of::<isize>() * 7);
 }
 
 #[test]

crsn/src/asm/error.rs

@@ -8,18 +8,34 @@ use sexp::SourcePosition;
 use crate::asm::data::{Register};
 use crate::asm::data::literal::Label;
 use crate::asm::instr::Cond;
+use std::io;
 
 /// csn_asm unified error type
 #[derive(Error, Debug)]
 pub enum CrsnError {
-    #[error("S-expression parsing error: {0:?}")]
+    #[error("S-expression parsing error: {0}")]
     Sexp(#[from] Box<sexp::Error>),
-    #[error("Parse error: {0:?} at {1:?}")]
+    #[error("Parse error: {0} at {1}")]
     Parse(Cow<'static, str>, SourcePosition),
-    #[error("Parse error: {0:?} at {1:?}")]
+    #[error("Parse error: {0} at {1}")]
     ParseOther(Box<dyn Error + Send + Sync>, SourcePosition),
-    #[error("Assembler error: {0:?} at {1:?}")]
+    #[error("Assembler error: {0} at {1}")]
     Asm(AsmError, SourcePosition),
+    #[error("IO error: {0}")]
+    IOError(#[from] io::Error),
+}
+
+impl CrsnError {
+    /// Get error pos
+    pub fn pos(&self) -> Option<&SourcePosition> {
+        match self {
+            CrsnError::Parse(_, p) => Some(p),
+            CrsnError::ParseOther(_, p) => Some(p),
+            CrsnError::Asm(_, p) => Some(p),
+            CrsnError::Sexp(se) => Some(&se.pos),
+            CrsnError::IOError(_) =>None,
+        }
+    }
 }
 
 /// Error from the assembler stage (after parsing S-expressions and basic validation)
@@ -33,8 +49,10 @@ pub enum AsmError {
     DiscardAsValue,
     #[error("Conditional branch already defined for \"{0}\"")]
     ConditionalAlreadyUsed(Cond),
-    #[error("Label \"{0:?}\" not defined")]
+    #[error("Label \"{0}\" not defined")]
     LabelNotDefined(Label),
+    #[error("Label \"{0}\" already defined in this scope")]
+    LabelDuplicate(Label),
     #[error("Bad register type: {0}")]
     BadRegisterType(Register),
 }

crsn/src/asm/instr/flatten.rs

@@ -29,6 +29,16 @@ impl Flatten for () {
     }
 }
 
+impl Flatten for Op {
+    fn flatten(self: Box<Self>, _label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError> {
+        Ok(vec![*self])
+    }
+
+    fn pos(&self) -> SourcePosition {
+        self.pos.clone()
+    }
+}
+
 impl Flatten for InstrWithBranches {
     fn pos(&self) -> SourcePosition {
         self.pos.clone()
@@ -111,6 +121,23 @@ impl Flatten for Vec<Box<dyn Flatten>> {
     }
 }
 
+impl Flatten for Vec<Op> {
+    fn pos(&self) -> SourcePosition {
+        match self.first() {
+            None => {
+                Default::default()
+            }
+            Some(f) => {
+                f.pos()
+            }
+        }
+    }
+
+    fn flatten(self: Box<Self>, _label_num: &AtomicU32) -> Result<Vec<Op>, CrsnError> {
+        Ok(*self)
+    }
+}
+
 impl Flatten for Routine {
     fn pos(&self) -> SourcePosition {
         self.pos.clone()
@@ -138,15 +165,19 @@ impl Flatten for Routine {
             }.into_op(self_pos)
         );
 
-        labels_to_skips(ops)
+        jumps_to_skips(ops)
     }
 }
 
 /// Convert jumps to relative skips
-pub fn labels_to_skips(ops: Vec<Op>) -> Result<Vec<Op>, CrsnError> {
+pub fn jumps_to_skips(ops: Vec<Op>) -> Result<Vec<Op>, CrsnError> {
     let mut label_positions = HashMap::<Label, usize>::new();
     for (n, op) in ops.iter().enumerate() {
         if let OpKind::BuiltIn(BuiltinOp::Label(name)) = &op.kind {
+            if label_positions.contains_key(name) {
+                return Err(CrsnError::Asm(AsmError::LabelDuplicate(name.clone()), op.pos.clone()));
+            }
+
             label_positions.insert(name.clone(), n - label_positions.len());
         }
     }

crsn/src/asm/mod.rs

@@ -3,33 +3,33 @@ use std::sync::Arc;
 
 use sexp::SourcePosition;
 
-use crate::asm::instr::flatten::labels_to_skips;
+use crate::asm::instr::flatten::jumps_to_skips;
 use crate::asm::parse::{ParserContext, ParserState};
 use crate::module::{CrsnExtension, CrsnUniq};
 use crate::runtime::program::Program;
 use crate::builtin::BuiltinOps;
 use crate::runtime::run_thread::{RunState, ThreadInfo, ThreadToken};
 use crate::runtime::frame::REG_COUNT;
+use std::sync::atomic::AtomicU32;
+use std::path::{Path};
 
 pub mod data;
 pub mod error;
 pub mod instr;
 pub mod parse;
 pub mod patches;
+mod read_file;
+use read_file::read_file;
 
-/// Parse a program from string and assemble a low level instruction sequence from it.
-pub fn assemble(source: &str, uniq : &CrsnUniq, mut parsers: Vec<Box<dyn CrsnExtension>>) -> Result<Arc<Program>, error::CrsnError> {
-    parsers.insert(0, BuiltinOps::new());
-    for p in &mut parsers {
-        p.init(uniq);
-    }
+pub(crate) fn read_source_file(path: impl AsRef<Path>) -> Result<String, error::CrsnError> {
+    trace!("Read source file: {}", path.as_ref().display());
 
-    let parsers_arc = Arc::new(parsers);
+    let source = read_file(path)?;
 
     // remove first line if it looks like a shebang
-    let source = if source.starts_with("#!") {
+    let s = if source.starts_with("#!") {
         if let Some(nl) = source.find('\n') {
-            &source[nl + 1..]
+            (&source[nl + 1..]).to_string()
         } else {
             source
         }
@@ -37,15 +37,34 @@ pub fn assemble(source: &str, uniq : &CrsnUniq, mut parsers: Vec<Box<dyn CrsnExt
         source
     };
 
+    Ok(s)
+}
+
+/// Parse a program from string and assemble a low level instruction sequence from it.
+pub fn assemble(path: impl AsRef<Path>, uniq : &CrsnUniq, mut parsers: Vec<Box<dyn CrsnExtension>>) -> Result<Arc<Program>, error::CrsnError> {
+    parsers.insert(0, BuiltinOps::new());
+    for p in &mut parsers {
+        p.init(uniq);
+    }
+
+    let path = path.as_ref().canonicalize()?;
+    let source = read_source_file(&path)?;
+
+    let parsers_arc = Arc::new(parsers);
+
     let ti = Arc::new(ThreadInfo {
         id: ThreadToken(0),
         uniq: Default::default(),
-        program: Program::new(vec![], parsers_arc.clone()).unwrap(),
+        program: Program::new(vec![], parsers_arc.clone(), vec![path.clone()]).unwrap(),
         cycle_time: Default::default(),
         scheduler_interval: Default::default(),
         extensions: parsers_arc.clone(),
     });
 
+    /* numbered labels start with a weird high number
+    to avoid conflicts with user-defined numbered labels */
+    let label_num = Arc::new(AtomicU32::new(0x7890_0000));
+
     let pcx = ParserContext {
         parsers: &parsers_arc,
         state: RefCell::new(ParserState {
@@ -62,15 +81,32 @@ pub fn assemble(source: &str, uniq : &CrsnUniq, mut parsers: Vec<Box<dyn CrsnExt
                 parked: Default::default(),
                 global_regs: [0; REG_COUNT],
                 ext_data: Default::default(),
-                cr_deadline: None
+                cr_deadline: None,
+                critical_section: 0,
             },
             const_eval_ti: ti,
-            parsing_expr: false
+            parsing_expr: false,
+            label_num: label_num.clone(),
+            files: vec![
+                path,
+            ],
+            active_file: 0
         }),
     };
 
-    let ops = parse::parse(source, &SourcePosition::default(), &pcx)?;
-    let ops = labels_to_skips(ops)?;
+    let res = do_parse(&source, &pcx, parsers_arc.clone());
+    if let Err(e) = &res {
+        if let Some(pos) = e.pos() {
+            let f = pcx.state.borrow().files[pos.file as usize].clone();
+            eprintln!("Error in source file: {}", f.display());
+        }
+    }
+    res
+}
+
+fn do_parse(source: &str, pcx : &ParserContext, parsers_arc : Arc<Vec<Box<dyn CrsnExtension>>>) -> Result<Arc<Program>, error::CrsnError> {
+    let ops = parse::parse(source, &SourcePosition::default(), pcx)?;
+    let ops = jumps_to_skips(ops)?;
 
-    Ok(Program::new(ops, parsers_arc)?)
+    Ok(Program::new(ops, parsers_arc, pcx.state.borrow_mut().files.split_off(0))?)
 }

crsn/src/asm/parse/arg_parser.rs

@@ -109,7 +109,7 @@ impl<'a> TokenParser<'a> {
     }
 
     /// Look at the next entry
-    pub fn peek(&mut self) -> Option<&Sexp> {
+    pub fn peek(&self) -> Option<&Sexp> {
         self.args.last()
     }
 

crsn/src/asm/parse/mod.rs

@@ -13,6 +13,7 @@ use crate::asm::parse::sexp_expect::expect_list;
 use crate::module::CrsnExtension;
 use crate::runtime::run_thread::{ThreadInfo, RunState};
 use std::sync::Arc;
+use std::path::PathBuf;
 
 pub mod parse_cond;
 pub mod parse_instr;
@@ -51,14 +52,31 @@ pub struct ParserState {
 
     /// True if we are in an expression parser context
     pub parsing_expr : bool,
+
+    /// Label numberer
+    pub label_num : Arc<AtomicU32>,
+
+    /// Numbered files
+    pub files : Vec<PathBuf>,
+
+    /// Active file number. Is backed up before descending into a sub-file, and restored afterwards.
+    pub active_file: usize,
+}
+
+impl ParserState {
+    pub fn reset(&mut self) {
+        self.global_reg_aliases.clear();
+        self.reg_aliases.clear();
+        self.reg_alias_stack.clear();
+        self.constants.clear();
+        self.parsing_expr = false;
+        self.const_eval.reset();
+    }
 }
 
 pub fn parse(source: &str, pos: &SourcePosition, parsers: &ParserContext) -> Result<Vec<Op>, CrsnError> {
     let (items, _pos) = expect_list(sexp::parse(source)?, true)?;
 
-    /* numbered labels start with a weird high number
-    to avoid conflicts with user-defined numbered labels */
-    let label_num = AtomicU32::new(0x7890_0000);
     parse_instructions(items.into_iter(), pos, parsers)?
-        .flatten(&label_num)
+        .flatten(&parsers.state.borrow().label_num)
 }

crsn/src/asm/parse/parse_data.rs

@@ -124,7 +124,7 @@ pub fn parse_data_disp(tok: Sexp, pcx: &ParserContext) -> Result<DataDisp, CrsnE
                 }
 
                 let mut state_mut = pcx.state.borrow_mut();
-                state_mut.const_eval.clear_all();
+                state_mut.const_eval.reset();
 
                 let ticl = state_mut.const_eval.thread_info.clone();
                 op.execute(&ticl, &mut state_mut.const_eval)

crsn/src/asm/parse/parse_instr.rs

@@ -6,15 +6,20 @@ use crate::asm::parse::arg_parser::TokenParser;
 use crate::asm::parse::parse_cond::parse_cond_branch;
 use crate::asm::parse::parse_routine::parse_routine;
 use crate::asm::parse::ParserContext;
-use crate::asm::parse::sexp_expect::{expect_list, expect_string_atom};
+use crate::asm::parse::sexp_expect::{expect_list, expect_string_atom, expect_any_string_atom};
 use crate::asm::patches::NextOrErr;
 use crate::module::ParseRes;
+use crate::asm::patches::ErrSetFile;
 
 use super::parse_op::parse_op;
+use std::path::{PathBuf};
+use std::convert::TryFrom;
+use crate::asm::read_source_file;
+
 
 pub fn parse_instructions(items: impl Iterator<Item=Sexp>, pos: &SourcePosition, pcx: &ParserContext) -> Result<Box<dyn Flatten>, CrsnError> {
-    let mut parsed = vec![];
-    for expr in items {
+    let mut parsed: Vec<Box<dyn Flatten>> = vec![];
+    'exprs: for expr in items {
         let (tokens, listpos) = expect_list(expr, false)?;
 
         let mut toki = tokens.into_iter();
@@ -28,6 +33,84 @@ pub fn parse_instructions(items: impl Iterator<Item=Sexp>, pos: &SourcePosition,
             }
         }
 
+        if name == "include" {
+            // TODO move this to a separate function and get rid of err_file()
+
+            if parsing_expr {
+                return Err(CrsnError::Parse("Illegal syntax in const expression".into(), pos.clone()));
+            }
+
+            let (mut path, _namepos) = expect_any_string_atom(toki.next_or_err(listpos.clone(), "Expected file path or name to include")?)?;
+
+            // add extension if missing
+            let last_piece = path.split('/').rev().next().unwrap();
+            if !last_piece.contains('.') {
+                path.push_str(".csn");
+            }
+
+            trace!("*** include, raw path: {}", path);
+
+            let state = pcx.state.borrow();
+            let this_file = &state.files[state.active_file];
+
+            let new_file = PathBuf::try_from(path).unwrap();
+
+            let new_pb = if !new_file.is_absolute() {
+                let parent = this_file.parent().expect("file has parent");
+
+                let fixed = parent.join(&new_file);
+                trace!("Try to resolve: {}", fixed.display());
+
+                fixed.canonicalize()?
+            } else {
+                new_file.to_owned()
+            };
+            drop(state);
+            drop(new_file);
+
+            let (old_af, af) = {
+                let mut state = pcx.state.borrow_mut();
+                let old_af = state.active_file;
+                let af = state.files.len();
+                state.active_file = af;
+                state.files.push(new_pb.clone());
+                (old_af, af as u32)
+            };
+
+            let loaded = read_source_file(&new_pb)
+                .err_file(af)?;
+
+            let (items, _pos) =
+                expect_list(
+                    sexp::parse(&loaded)
+                        .map_err(|mut e| {
+                            e.pos.file = af;
+                            e
+                        })?,
+                    true)
+                .err_file(af)?;
+
+            let sub_parsed = parse_instructions(items.into_iter(), pos, pcx)
+                .err_file(af)?;
+
+            let mut flat = sub_parsed.flatten(&pcx.state.borrow().label_num)
+                .err_file(af)?;
+
+            flat.iter_mut().for_each(|op| {
+                op.pos.file = af as u32;
+            });
+
+            trace!("inner falt {:#?}", flat);
+
+            parsed.push(Box::new(flat));
+
+            {
+                let mut state = pcx.state.borrow_mut();
+                state.active_file = old_af;
+            }
+            continue;
+        }
+
         if name == "proc" {
             if parsing_expr {
                 return Err(CrsnError::Parse("Illegal syntax in const expression".into(), pos.clone()));
@@ -40,8 +123,13 @@ pub fn parse_instructions(items: impl Iterator<Item=Sexp>, pos: &SourcePosition,
         let mut token_parser = TokenParser::new(toki.collect(), &listpos, pcx);
         for p in pcx.parsers {
             token_parser = match p.parse_syntax(pos, &name, token_parser) {
-                Ok(ParseRes::Parsed(op)) => return Ok(op),
-                Ok(ParseRes::ParsedNone) => return Ok(Box::new(())),
+                Ok(ParseRes::Parsed(op)) => {
+                    parsed.push(op);
+                    continue 'exprs;
+                },
+                Ok(ParseRes::ParsedNone) => {
+                    continue 'exprs;
+                },
                 Ok(ParseRes::Unknown(to_reuse)) => {
                     if to_reuse.parsing_started() {
                         panic!("Module \"{}\" started parsing syntax, but returned Unknown!", p.name());

crsn/src/asm/patches/mod.rs

@@ -57,3 +57,24 @@ impl<T, E: std::error::Error + Send + Sync + 'static> ErrWithPos<T> for Result<T
         }
     }
 }
+
+pub trait ErrSetFile<T> {
+    fn err_file(self, file: u32) -> Result<T, CrsnError>;
+}
+
+impl<T> ErrSetFile<T> for Result<T, CrsnError> {
+    /// Set file context in the error
+    fn err_file(self, file: u32) -> Result<T, CrsnError> {
+        match self {
+            Ok(v) => Ok(v),
+            Err(CrsnError::Parse(a, p)) => Err(CrsnError::Parse(a, p.with_file(file))),
+            Err(CrsnError::ParseOther(a, p)) => Err(CrsnError::ParseOther(a, p.with_file(file))),
+            Err(CrsnError::Asm(a, p)) => Err(CrsnError::Asm(a, p.with_file(file))),
+            Err(CrsnError::Sexp(mut se)) => {
+                se.pos.file = file;
+                Err(CrsnError::Sexp(se))
+            },
+            Err(other @ CrsnError::IOError(_)) => Err(other),
+        }
+    }
+}

crsn/src/asm/read_file.rs

@@ -4,7 +4,7 @@ use std::io::Read;
 use std::path::Path;
 
 /// Read a file to string
-pub fn read_file<P: AsRef<Path>>(path: P) -> io::Result<String> {
+pub fn read_file(path: impl AsRef<Path>) -> io::Result<String> {
     let path = path.as_ref();
     let mut file = File::open(path)?;
 

crsn/src/builtin/defs.rs

@@ -151,6 +151,12 @@ pub enum BuiltinOp {
     /// Yield control, optionally yielding a value that must be consumed (by reading the task handle)
     /// before execution can resume
     Yield { value: Option<Rd> },
+    /// Set runtime option
+    RuntimeOpt { opt: Rd, value: Rd },
+    /// Begin critical section
+    CriticalBegin,
+    /// End critical section
+    CriticalEnd,
     /// Deny jumps, skips and run across this address, producing a run-time fault.
     Barrier {
         kind: Barrier,

crsn/src/builtin/exec.rs

@@ -10,6 +10,8 @@ use crate::runtime::frame::StackFrame;
 use crate::runtime::run_thread::{state::RunState, ThreadInfo};
 use crate::asm::instr::cond::Flag;
 
+use super::RT_OPT_TIMESLICE;
+
 impl OpTrait for BuiltinOp {
     fn execute(&self, info: &ThreadInfo, state: &mut RunState) -> Result<EvalRes, Fault> {
         let program = &info.program;
@@ -89,7 +91,7 @@ impl OpTrait for BuiltinOp {
                             values.push(state.read(arg)?);
                         }
 
-                        let mut frame2 = StackFrame::new(pos, &values);
+                        let frame2 = StackFrame::new(pos, &values);
                         let handle_val = state.add_coroutine(frame2);
                         state.write(handle, handle_val)?;
 
@@ -252,6 +254,35 @@ impl OpTrait for BuiltinOp {
             BuiltinOp::Join(obj) => {
                 res.sched = SchedSignal::Join(obj.read(state)?);
             }
+            BuiltinOp::RuntimeOpt { opt, value } => {
+                let opt = state.read(opt)?;
+                let val = state.read(value)?;
+
+                match opt {
+                    RT_OPT_TIMESLICE => {
+                        *state.thread_info.scheduler_interval.write() = Duration::from_micros(val);
+                    }
+                    _ => {
+                        warn!("Invalid rt-opt {}", opt);
+                        state.set_flag(Flag::Invalid, true);
+                    }
+                }
+
+            }
+            BuiltinOp::CriticalBegin => {
+                if state.critical_section == Value::MAX {
+                    return Err(Fault::UnbalancedCriticalSection);
+                }
+                state.critical_section += 1;
+                res.cycles = 0;
+            }
+            BuiltinOp::CriticalEnd => {
+                if state.critical_section == 0 {
+                    return Err(Fault::UnbalancedCriticalSection);
+                }
+                state.critical_section -= 1;
+                res.cycles = 0;
+            }
         }
 
         Ok(res)

crsn/src/builtin/mod.rs

@@ -1,14 +1,23 @@
-use sexp::SourcePosition;
+use sexp::{SourcePosition, Sexp, Atom};
 
 use crate::asm::error::CrsnError;
 use crate::asm::instr::op::OpKind;
 use crate::asm::parse::arg_parser::TokenParser;
 use crate::module::{CrsnExtension, ParseRes};
+use crate::asm::data::literal::{Value, Label};
+use crate::asm::instr::{Flatten, Op};
+use crate::asm::parse::parse_instructions;
+use crate::builtin::defs::BuiltinOp;
+use crate::asm::instr::flatten::jumps_to_skips;
+use crate::asm::data::{Rd, RdData};
+use crate::asm::parse::parse_data::parse_label;
 
 pub mod defs;
 pub mod exec;
 pub mod parse;
 
+pub(crate) const RT_OPT_TIMESLICE : u64 = 1;
+
 #[derive(Debug, Clone)]
 pub struct BuiltinOps;
 
@@ -26,4 +35,116 @@ impl CrsnExtension for BuiltinOps {
     fn parse_op<'a>(&self, pos: &SourcePosition, keyword: &str, args: TokenParser<'a>) -> Result<ParseRes<'a, OpKind>, CrsnError> {
         parse::parse_op(pos, keyword, args)
     }
+
+    /// Get value of an extension-provided constant.
+    /// This constant may be an object handle, or a constant value used as argument in some other instruction.
+    fn get_constant_value<'a>(&self, name: &str) -> Option<Value> {
+        match name {
+            "RT_TIMESLICE" => Some(RT_OPT_TIMESLICE),
+            _ => None,
+        }
+    }
+
+    /// Parse a generic S-expression (non-op) that started with the given keyword
+    ///
+    /// pcx is available on the arg_tokens parser
+    fn parse_syntax<'a>(&self, pos: &SourcePosition, keyword: &str, mut tokens: TokenParser<'a>)
+                        -> Result<ParseRes<'a, Box<dyn Flatten>>, CrsnError>
+    {
+        if keyword == "crit" || keyword == "critical" {
+            let pcx = tokens.pcx;
+            let opts = parse_instructions(tokens.into_iter(), pos, pcx)?;
+
+            let flattened = jumps_to_skips(opts.flatten(&pcx.state.borrow_mut().label_num)?)?;
+
+            let len = flattened.len();
+
+            for (n, op) in flattened.iter().enumerate() {
+                match op.kind {
+                    OpKind::BuiltIn(BuiltinOp::Skip(Rd(RdData::Immediate(skip)))) => {
+                        let signed = i64::from_ne_bytes(skip.to_ne_bytes());
+                        let target = n as i64 + signed;
+                        if target < 0 || target > len as i64 {
+                            return Err(CrsnError::Parse("Cannot jump out of a critical section!".into(), op.pos()));
+                        }
+                    }
+                    /* Non-constant skip cannot be validated */
+                    OpKind::BuiltIn(BuiltinOp::Skip(_)) => {
+                        return Err(CrsnError::Parse("Variable skips are not allowed in a critical section".into(), op.pos()));
+                    }
+                    /* Yield in critical makes zero sense */
+                    OpKind::BuiltIn(BuiltinOp::Yield { .. }) => {
+                        return Err(CrsnError::Parse("Yield in a critical section!".into(), op.pos()));
+                    }
+                    /* This is likely a bug */
+                    OpKind::BuiltIn(BuiltinOp::Ret(_)) => {
+                        return Err(CrsnError::Parse("Ret in a critical section!".into(), op.pos()));
+                    }
+                    /* Probably also a bug. If someone really wants this, they can start and end the critical section manually. */
+                    OpKind::BuiltIn(BuiltinOp::FarJump(_)) => {
+                        return Err(CrsnError::Parse("Far jump a critical section!".into(), op.pos()));
+                    }
+                    _ => {}
+                }
+            }
+
+            let vec : Vec<Box<dyn Flatten>> = vec![
+                Box::new(Op {
+                    kind: OpKind::BuiltIn(BuiltinOp::CriticalBegin),
+                    cond: None,
+                    pos: pos.clone(),
+                }),
+                Box::new(flattened),
+                Box::new(Op {
+                    kind: OpKind::BuiltIn(BuiltinOp::CriticalEnd),
+                    cond: None,
+                    pos: pos.clone(),
+                }),
+            ];
+
+            return Ok(ParseRes::Parsed(Box::new(vec)));
+        }
+
+        if keyword == "loop" {
+            let mut end_label = None;
+            let label = if let Some(Sexp::Atom(Atom::S(_), _)) = tokens.peek() {
+                let label = parse_label(tokens.next().unwrap())?;
+                if let Label::Named(n) = &label {
+                    end_label = Some(Label::Named(format!("{}-end", n)));
+                }
+                label
+            } else {
+                Label::unique(&tokens.pcx.state.borrow().label_num)
+            };
+
+            let pcx = tokens.pcx;
+            let inner = parse_instructions(tokens.into_iter(), pos, pcx)?;
+
+            let mut vec : Vec<Box<dyn Flatten>> = vec![
+                Box::new(Op {
+                    kind: OpKind::BuiltIn(BuiltinOp::Label(label.clone())),
+                    cond: None,
+                    pos: pos.clone(),
+                }),
+                inner,
+                Box::new(Op {
+                    kind: OpKind::BuiltIn(BuiltinOp::Jump(label)),
+                    cond: None,
+                    pos: pos.clone(),
+                }),
+            ];
+
+            if let Some(el) = end_label {
+                vec.push(Box::new(Op {
+                    kind: OpKind::BuiltIn(BuiltinOp::Label(el)),
+                    cond: None,
+                    pos: pos.clone(),
+                }));
+            }
+
+            return Ok(ParseRes::Parsed(Box::new(vec)))
+        }
+
+        Ok(ParseRes::Unknown(tokens))
+    }
 }

crsn/src/builtin/parse.rs

@@ -1,4 +1,4 @@
-use sexp::{Atom, Sexp, SourcePosition, atom_qs, atom_s};
+use sexp::{Atom, Sexp, SourcePosition, atom_qs};
 
 use crate::asm::data::literal::{RoutineName};
 use crate::asm::data::reg::parse_reg;
@@ -183,6 +183,21 @@ pub(crate) fn parse_op<'a>(op_pos: &SourcePosition, keyword: &str, mut args: Tok
             })
         }
 
+        "crit-begin" => {
+            BuiltinOp::CriticalBegin
+        }
+
+        "crit-end" => {
+            BuiltinOp::CriticalEnd
+        }
+
+        "rt-opt" => {
+            BuiltinOp::RuntimeOpt {
+                opt: args.next_rd()?,
+                value: args.next_rd()?,
+            }
+        }
+
         "ld" => {
             BuiltinOp::Load {
                 dst: args.next_wr()?,
@@ -349,6 +364,9 @@ pub(crate) fn parse_routine_name(name: String, pos: &SourcePosition) -> Result<R
 
 pub(crate) fn to_sexp(op: &BuiltinOp) -> Sexp {
     match op {
+        BuiltinOp::CriticalBegin => sexp::list(&[A("crit-begin")]),
+        BuiltinOp::CriticalEnd => sexp::list(&[A("crit-end")]),
+        BuiltinOp::RuntimeOpt { opt, value } => sexp::list(&[A("rt-opt"), A(opt), A(value)]),
         BuiltinOp::Nop => sexp::list(&[A("nop")]),
         BuiltinOp::Halt => sexp::list(&[A("halt")]),
         BuiltinOp::Sleep { count: micros, unit_us: SleepUnit::Sec } => sexp::list(&[A("sslp"), A(micros)]),
@@ -452,7 +470,7 @@ pub(crate) fn to_sexp(op: &BuiltinOp) -> Sexp {
             if args.is_empty() {
                 sexp::list(&[A("spawn"), A(handle), A(proc)])
             } else {
-                let mut v = vec![A("spawn"), A(handle), A(proc)];
+                let mut v = vec![A("spawn"), A(handle), A(&proc.name)];
                 v.extend(args.iter().map(|r| A(r)));
                 sexp::list(&v)
             }
@@ -473,10 +491,15 @@ mod test {
 
     use sexp::SourcePosition;
 
-    use crate::asm::parse::{parse_instructions, ParserContext};
+    use crate::asm::parse::{parse_instructions, ParserContext, ParserState};
     use crate::asm::parse::sexp_expect::expect_list;
     use crate::builtin::BuiltinOps;
     use crate::module::OpTrait;
+    use std::cell::RefCell;
+    use std::sync::Arc;
+    use crate::runtime::run_thread::{ThreadInfo, ThreadToken, RunState};
+    use crate::runtime::program::Program;
+    use crate::runtime::frame::REG_COUNT;
 
     #[test]
     fn roundtrip() {
@@ -562,13 +585,46 @@ mod test {
 
         let parser = BuiltinOps::new();
 
-        let parsers = &[parser];
+        let parsers = Arc::new(vec![parser]);
+
+        let ti = Arc::new(ThreadInfo {
+            id: ThreadToken(0),
+            uniq: Default::default(),
+            program: Program::new(vec![], parsers.clone(), vec![]).unwrap(),
+            cycle_time: Default::default(),
+            scheduler_interval: Default::default(),
+            extensions: parsers.clone(),
+        });
+
+        let pcx = ParserContext {
+            parsers: &parsers,
+            state: RefCell::new(ParserState {
+                reg_aliases: Default::default(),
+                reg_alias_stack: vec![],
+                global_reg_aliases: Default::default(),
+                constants: Default::default(),
+
+                // This is a fake thread to pass to constant expressions when evaluating them.
+                // This allows to evaluate nearly all instructions at compile time.
+                const_eval: RunState {
+                    thread_info: ti.clone(),
+                    cr: Default::default(),
+                    parked: Default::default(),
+                    global_regs: [0; REG_COUNT],
+                    ext_data: Default::default(),
+                    cr_deadline: None,
+                    critical_section: 0,
+                },
+                const_eval_ti: ti.clone(),
+                parsing_expr: false,
+                label_num: Default::default(),
+                files: vec![],
+                active_file: 0
+            }),
+        };
 
         for (sample, expected) in samples {
-            let pcx = ParserContext {
-                parsers,
-                state: Default::default(),
-            };
+            pcx.state.borrow_mut().reset();
 
             println!("Parse: {}", sample);
 
@@ -587,10 +643,7 @@ mod test {
             assert_eq!(expected, exported);
 
             println!(" - 2nd cycle");
-            let pcx = ParserContext {
-                parsers,
-                state: Default::default(),
-            };
+            pcx.state.borrow_mut().reset();
 
             /* second cycle, nothing should change */
             let s = sexp::parse(&format!("({})", exported))

crsn/src/runtime/fault.rs

@@ -77,6 +77,18 @@ pub enum Fault {
 
     #[error("Attempt to read undefined extension data store")]
     ExtDataNotDefined,
+
+    #[error("Unbalanced critical sections")]
+    UnbalancedCriticalSection,
+
+    #[error("Deadlock detected")]
+    Deadlock,
+
+    #[error("Root routine returned or yielded a value")]
+    RootReturned,
+
+    #[error("System IO error: {0}")]
+    IOError(#[from] std::io::Error),
 }
 
 #[derive(Error, Debug)]

crsn/src/runtime/program.rs

@@ -10,6 +10,7 @@ use crate::asm::instr::op::OpKind;
 use crate::builtin::defs::{Barrier, BuiltinOp};
 use crate::module::CrsnExtension;
 use crate::runtime::fault::Fault;
+use std::path::PathBuf;
 
 #[derive(Debug)]
 pub struct Program {
@@ -20,16 +21,23 @@ pub struct Program {
     /// Barriers from-to (inclusive).
     /// Standalone barriers have both addresses the same.
     barriers: Vec<(Addr, Addr)>,
+    /// This is used at runtime to better report error locations when included files are used
+    pub(crate) file_names: Vec<PathBuf>,
 }
 
 impl Program {
-    pub fn new(ops: Vec<Op>, extensions: Arc<Vec<Box<dyn CrsnExtension>>>) -> Result<Arc<Self>, CrsnError> {
+    pub fn new(
+        ops: Vec<Op>,
+        extensions: Arc<Vec<Box<dyn CrsnExtension>>>,
+        file_names: Vec<PathBuf>,
+    ) -> Result<Arc<Self>, CrsnError> {
         let mut p = Self {
             ops,
             extensions,
             routines: Default::default(),
             far_labels: Default::default(),
             barriers: Default::default(),
+            file_names,
         };
         p.scan()?;
         Ok(Arc::new(p))
@@ -100,6 +108,7 @@ impl Program {
                     line: 0,
                     column: 0,
                     index: 0,
+                    file: 0,
                 },
                 cond: None,
             }

crsn/src/runtime/run_thread.rs

@@ -1,6 +1,5 @@
 use std::sync::Arc;
 
-use std::thread::JoinHandle;
 use std::time::{Duration, Instant};
 
 pub use info::ThreadInfo;
@@ -14,6 +13,8 @@ use crate::runtime::program::Program;
 use crate::runtime::run_thread::state::{CoroutineContext, CoroutineState};
 use std::{mem, thread};
 use crate::asm::instr::cond::Flag;
+use parking_lot::RwLock;
+use crate::asm::instr::Flatten;
 
 #[derive(Clone, Copy, Eq, PartialEq, Debug, Ord, PartialOrd)]
 pub struct ThreadToken(pub u32);
@@ -40,27 +41,30 @@ impl RunThread {
     pub fn new(params: ThreadParams) -> Self {
         let extensions = params.program.extensions.clone();
 
+        // TODO investigate if this division to 2 structs is still needed
+
         let ti = Arc::new(ThreadInfo {
             id: params.id,
             uniq: params.uniq,
             program: params.program,
             cycle_time: params.cycle_time,
-            scheduler_interval: params.scheduler_interval,
+            scheduler_interval: RwLock::new(params.scheduler_interval),
             extensions,
         });
 
         let rs = RunState {
             thread_info: ti.clone(),
-            cr: CoroutineContext {
+            cr: Box::new(CoroutineContext {
                 handle: 0, // this is the root
                 frame: StackFrame::new(params.pc, params.args),
                 call_stack: vec![],
                 cr_state: Default::default(),
-            },
+            }),
             parked: Default::default(),
             global_regs: [0; REG_COUNT],
             ext_data: Default::default(),
-            cr_deadline: None
+            cr_deadline: None,
+            critical_section: 0,
         };
 
         Self {
@@ -69,21 +73,17 @@ impl RunThread {
         }
     }
 
-    /// Spawn as a thread
-    pub fn spawn(self) -> JoinHandle<()> {
-        std::thread::spawn(move || {
-            self.run();
-        })
-    }
-
     /// Start synchronously
     pub fn run(mut self) {
         let mut loop_helper = spin_sleep::LoopHelper::builder()
             .build_with_target_rate(1.0/self.info.cycle_time.as_secs_f64());
 
         loop_helper.loop_start();
-        'run: loop {
+        let mut orig_pc;
+
+        let fault = 'run: loop {
             let mut want_switch = false;
+            orig_pc = self.state.cr.frame.pc;
             match self.eval_op() {
                 Ok(EvalRes { cycles, advance, sched }) => {
                     for _ in 0..cycles {
@@ -91,7 +91,6 @@ impl RunThread {
                         loop_helper.loop_start();
                     }
                     trace!("Step {}; Status = {}", advance, self.state.cr.frame.status);
-                    let orig_pc = self.state.cr.frame.pc;
                     self.state.cr.frame.pc.advance(advance);
 
                     if let Some(dl) = self.state.cr_deadline {
@@ -126,7 +125,7 @@ impl RunThread {
                             'find: for (n, th) in self.state.parked.iter_mut().enumerate() {
                                 if th.handle == handle {
                                     if let CoroutineState::Finished(_) = &th.cr_state {
-                                        let mut crs = mem::replace(&mut th.cr_state, CoroutineState::Ready);
+                                        let crs = mem::replace(&mut th.cr_state, CoroutineState::Ready);
                                         self.state.parked.remove(n); // delete it
                                         found = true;
 
@@ -154,83 +153,141 @@ impl RunThread {
                     }
                 }
                 Err(Fault::Blocked) => {
-                    // Do not advance, the last instruction will be re-tried
+                    trace!("Thread reports being blocked!");
+                    self.state.cr.frame.pc = orig_pc; // Retry
+                    self.state.cr.cr_state = CoroutineState::Ready;
                     want_switch = true;
                 }
-                Err(Fault::Halt) => {
-                    // TODO implement coordinated shutdown when more threads are running!
-                    break 'run;
-                }
                 Err(e) => {
-                    error!("Fault: {:?}", e);
-                    error!("Core dump: {:?}", self.state);
-                    break 'run;
+                    break 'run e;
                 }
             }
 
-            if want_switch {
-                trace!("Switch requested");
+            // Resolve the next coroutine to run, or wait a bit...
+            'next: loop {
+                if want_switch {
+                    let now = Instant::now();
 
-                let now = Instant::now();
-
-                let mut candidate = None;
-                let mut closest_due = None;
-                for _ in 0..self.state.parked.len() {
-                    if let Some(mut rt) = self.state.parked.pop_front() {
-                        match rt.cr_state {
-                            CoroutineState::Ready => {
-                                candidate = Some(rt);
-                                break;
-                            }
+                    if self.state.critical_section > 0 {
+                        match self.state.cr.cr_state {
+                            CoroutineState::Ready => {}
                             CoroutineState::Sleep { due } => {
-                                if due <= now {
-                                    rt.cr_state = CoroutineState::Ready;
+                                let time = due.saturating_duration_since(now);
+                                trace!("Sleep in critical: {:?}", time);
+                                thread::sleep(time);
+                                continue 'run;
+                            }
+                            CoroutineState::Finished(_) | CoroutineState::YieldedValue(_) => {
+                                // This is not good
+                                break 'run Fault::Deadlock;
+                            }
+                        }
+
+                        // This is either a bug, or waiting for IO.
+                        // If it is the latter, try to give the OS a bit of breathing room..
+                        std::thread::yield_now();
+                        continue 'run;
+                    }
+
+                    trace!("Switch requested");
+
+                    let mut candidate = None;
+                    let mut closest_due = None;
+                    'findbest: for _ in 0..self.state.parked.len() {
+                        if let Some(mut rt) = self.state.parked.pop_front() {
+                            match rt.cr_state {
+                                CoroutineState::Ready => {
+                                    trace!("Found READY thread to run next");
                                     candidate = Some(rt);
-                                    break;
-                                } else {
-                                    match closest_due {
-                                        Some(d) => {
-                                            if d > due {
+                                    break 'findbest;
+                                }
+                                CoroutineState::Sleep { due } => {
+                                    if due <= now {
+                                        trace!("Found DUE sleeping thread to run next");
+                                        rt.cr_state = CoroutineState::Ready;
+                                        candidate = Some(rt);
+                                        break 'findbest;
+                                    } else {
+                                        match closest_due {
+                                            Some(d) => {
+                                                if d > due {
+                                                    closest_due = Some(due);
+                                                }
+                                            },
+                                            None => {
                                                 closest_due = Some(due);
                                             }
-                                        },
-                                        None => {
-                                            closest_due = Some(due);
                                         }
+                                        self.state.parked.push_back(rt);
                                     }
+                                }
+                                _ => {
                                     self.state.parked.push_back(rt);
                                 }
                             }
-                            _ => {
-                                self.state.parked.push_back(rt);
-                            }
                         }
                     }
-                }
 
-                if let Some(cr) = candidate {
-                    trace!("Context switch to {:?}", cr);
-
-                    // Do switch
-                    let old = mem::replace(&mut self.state.cr, cr);
-                    self.state.parked.push_back(old);
-                    self.state.cr_deadline = Some(now + self.info.scheduler_interval);
-                } else if let Some(due) = closest_due {
-                    let time = due.saturating_duration_since(now);
-                    trace!("No thread to switch to, sleep {:?}", time);
-                    thread::sleep(time);
+                    if let Some(cr) = candidate {
+                        trace!("Context switch to {:?}", cr);
+
+                        // Do switch
+                        let old = mem::replace(&mut self.state.cr, cr);
+                        self.state.parked.push_back(old);
+
+                        self.state.start_task_switching();
+
+                    } else if let Some(due) = closest_due {
+                        if self.state.cr.cr_state == CoroutineState::Ready {
+                            trace!("No candidate found to run, retry same thread.");
+                            // Let it run another quantum, maybe it was just blocked
+                            continue 'run;
+                        }
+
+                        let time = due.saturating_duration_since(now);
+                        trace!("No thread to switch to, sleep {:?}", time);
+                        thread::sleep(time);
+                        continue 'next;
+                    } else {
+                        // Nothing to run?
+                        thread::yield_now();
+                        trace!("No thread to switch to!");
+                    }
+
+                    let n_alive = self.state.parked.iter()
+                        .filter(|p| p.cr_state.is_alive()).count();
+
+                    if n_alive == 0 {
+                        trace!("Stop task switching, no parked threads are alive");
+                        self.state.stop_task_switching(); // This should improve performance in single-threaded mode
+                    }
+
+                    match self.state.cr.cr_state {
+                        CoroutineState::Finished(_) | CoroutineState::YieldedValue(_) => {
+                            break 'run Fault::RootReturned;
+                        }
+                        _ => {}
+                    }
                 }
 
-                let n_alive = self.state.parked.iter()
-                    .filter(|p| p.cr_state.is_alive()).count();
+                break 'next;
+            }
+        };
 
-                if n_alive == 0 {
-                    trace!("Stop task switching, no parked threads are alive");
-                    self.state.cr_deadline = None;
+        match fault {
+            Fault::Halt => {
+                debug!("Thread ended.");
+            }
+            e => {
+                eprintln!("*** Program failed: {} ***", e);
+                if let Some(instr) = self.info.program.ops.get(orig_pc.0 as usize) {
+                    eprintln!("Source location: {}, line {}, column {}", self.info.program.file_names[instr.pos().file as usize].display(), instr.pos().line, instr.pos().column);
+                } else {
+                    eprintln!("Instruction address: {}", orig_pc);
                 }
+
+                debug!("\nCore dump: {:?}", self.state);
             }
         }
-
-        debug!("Thread ended.");
     }
 }

crsn/src/runtime/run_thread/info.rs

@@ -6,6 +6,7 @@ use crate::asm::data::literal::Value;
 use crate::runtime::program::Program;
 use crate::runtime::run_thread::ThreadToken;
 use crate::module::{CrsnExtension, CrsnUniq};
+use parking_lot::RwLock;
 
 #[derive(Debug)]
 pub struct ThreadInfo {
@@ -18,7 +19,7 @@ pub struct ThreadInfo {
     /// Program to run
     pub(crate) cycle_time: Duration,
     /// Interval one thread/coroutine is let to run before the context switches
-    pub(crate) scheduler_interval: Duration,
+    pub(crate) scheduler_interval: RwLock<Duration>,
     /// Extensions
     pub extensions: Arc<Vec<Box<dyn CrsnExtension>>>,
 }

crsn/src/runtime/run_thread/state.rs

@@ -12,20 +12,22 @@ use nudge::{likely};
 use crate::asm::instr::cond::Flag;
 use std::fmt::{Debug, Formatter};
 use std::fmt;
-use std::time::Instant;
+use std::time::{Instant, Duration};
 
 pub struct RunState {
     pub thread_info: Arc<ThreadInfo>,
     /// The active coroutine
-    pub cr: CoroutineContext,
+    pub cr: Box<CoroutineContext>,
     /// Parked coroutines
-    pub parked: VecDeque<CoroutineContext>,
+    pub parked: VecDeque<Box<CoroutineContext>>,
     /// General purpose registers that stay valid for the entire run-time of the thread
     pub global_regs: [Value; REG_COUNT],
     /// Extension data
     pub ext_data: ExtensionDataStore,
     /// Execution deadline, if multi-tasked
     pub cr_deadline: Option<Instant>,
+    /// Nonzero if inside a critical section
+    pub critical_section: Value,
 }
 
 #[derive(Debug,Default)]
@@ -72,7 +74,7 @@ impl Default for CoroutineState {
 
 impl RunState {
     /// Clear everything. Caution: when done at runtime, this effectively reboots the thread
-    pub fn clear_all(&mut self) {
+    pub fn reset(&mut self) {
         self.cr = Default::default();
         self.parked = Default::default();
         self.global_regs = Default::default();
@@ -85,18 +87,32 @@ impl RunState {
         trace!("Spawn cr {:#}", handle);
 
         // front - so it runs ASAP
-        self.parked.push_front(CoroutineContext {
+        self.parked.push_front(Box::new(CoroutineContext {
             handle,
             frame,
             call_stack: vec![],
             cr_state: Default::default()
-        });
+        }));
         if self.cr_deadline.is_none() {
             // start context switching
-            self.cr_deadline = Some(Instant::now() + self.thread_info.scheduler_interval);
+            self.start_task_switching();
         }
         handle
     }
+
+    pub(crate) fn start_task_switching(&mut self) {
+        let ival = *self.thread_info.scheduler_interval.read();
+        if ival > Duration::default() {
+            self.cr_deadline = Some(Instant::now() + ival);
+        } else {
+            // Disabled
+            self.cr_deadline = None;
+        }
+    }
+
+    pub(crate) fn stop_task_switching(&mut self) {
+        self.cr_deadline = None;
+    }
 }
 
 impl Debug for RunState {

crsn_stdio/src/lib.rs

@@ -21,13 +21,29 @@ mod console {
 
     use std::ffi::c_void;
     use std::mem::{self, MaybeUninit};
+    use crsn::runtime::fault::Fault;
+    use std::time::{Instant};
+
+    struct ReadCharState {
+        bytes: [u8; 4],
+        cursor: usize,
+        len: usize,
+        last_timeout : u8,
+    }
+
+    static mut READ_CHAR_STATE: ReadCharState = ReadCharState {
+        bytes: [0; 4],
+        cursor: 0,
+        len: 0,
+        last_timeout : 0,
+    };
 
-    fn setup_fd(fd: RawFd) -> io::Result<libc::termios> {
+    fn setup_fd(fd: RawFd) -> Result<libc::termios, Fault> {
         use libc::*;
 
         let mut tio = MaybeUninit::uninit();
         if 0 != unsafe { tcgetattr(fd, tio.as_mut_ptr()) } {
-            return Err(io::Error::last_os_error());
+            return Err(Fault::IOError(io::Error::last_os_error()));
         }
         let mut tio = unsafe { MaybeUninit::assume_init(tio) };
         let old_tio : termios = unsafe { mem::transmute_copy(&tio) };
@@ -39,36 +55,76 @@ mod console {
         tio.c_cc[VMIN] = 1;
         tio.c_cc[VTIME] = 0;
         if 0 != unsafe { tcsetattr(fd, TCSANOW, &tio) } {
-            return Err(io::Error::last_os_error());
+            return Err(Fault::IOError(io::Error::last_os_error()));
         }
 
         Ok(old_tio)
     }
 
-    pub fn init_io() -> io::Result<libc::termios> {
+    pub fn init_io() -> Result<libc::termios, Fault> {
         setup_fd(libc::STDIN_FILENO)
     }
 
-    pub fn read_byte() -> io::Result<u8> {
+    pub fn read_byte(deadline : Option<Instant>) -> Result<u8, Fault> {
+        // Set TIO timeout
+        let state = unsafe { &mut READ_CHAR_STATE };
+
+        if (state.last_timeout == 0) && deadline.is_none() {
+            // Keep it like that
+        }  else {
+            let vtime = if let Some(dl) = deadline {
+                let timeout = dl.saturating_duration_since(Instant::now());
+                ((timeout.as_secs_f32() * 10.0).round() as u32).min(255).max(1) as u8
+            } else {
+                0
+            };
+
+            if state.last_timeout != vtime {
+                // vtime changes
+                state.last_timeout = vtime;
+
+                let mut tio = MaybeUninit::uninit();
+                if 0 != unsafe { libc::tcgetattr(libc::STDIN_FILENO, tio.as_mut_ptr()) } {
+                    return Err(Fault::IOError(io::Error::last_os_error()));
+                }
+                let mut tio = unsafe { MaybeUninit::assume_init(tio) };
+
+                if vtime > 0 {
+                    tio.c_cc[libc::VTIME] = vtime; /* unit = 0.1 */
+                    tio.c_cc[libc::VMIN] = 0;
+                } else {
+                    tio.c_cc[libc::VTIME] = 0; // no counting
+                    tio.c_cc[libc::VMIN] = 1; // want at least one character
+                }
+
+                unsafe { libc::tcsetattr(libc::STDIN_FILENO, libc::TCSANOW, &tio) };
+            }
+        }
+
         let mut buf = 0u8;
         let len = unsafe { libc::read(libc::STDIN_FILENO, &mut buf as *mut u8 as *mut c_void, 1) };
+
+        if len == 0 && state.last_timeout != 0 {
+            return Err(Fault::IOError(io::Error::new(std::io::ErrorKind::TimedOut, "")));
+        }
+
         if len <= 0 {
-            Err(io::Error::last_os_error())
+            Err(Fault::IOError(io::Error::last_os_error()))
         } else {
             Ok(buf as u8)
         }
     }
 
-    pub fn write_byte(b : u8) -> io::Result<()> {
+    pub fn write_byte(b : u8) -> Result<(), Fault> {
         let len = unsafe { libc::write(libc::STDOUT_FILENO, &b as *const u8 as *const c_void, 1) };
         if len <= 0 {
-            Err(io::Error::last_os_error())
+            Err(Fault::IOError(io::Error::last_os_error()))
         } else {
             Ok(())
         }
     }
 
-    pub fn write_char(c : char) -> io::Result<()> {
+    pub fn write_char(c : char) -> Result<(), Fault> {
         let mut buf = [0u8; 4];
         for b in c.encode_utf8(&mut buf).as_bytes() {
             write_byte(*b)?;
@@ -76,30 +132,43 @@ mod console {
         Ok(())
     }
 
-    pub fn read_char() -> io::Result<char> {
-        let first = read_byte()?;
+    pub fn read_char(deadline : Option<Instant>) -> Result<char, Fault> {
+        let state = unsafe { &mut READ_CHAR_STATE };
 
-        if first & 0x80 == 0 {
-            return Ok(first as char);
-        }
+        if state.cursor == 0 {
+            let first = read_byte(deadline)?;
 
-        let mut bytes = [first, 0, 0, 0];
+            if first & 0x80 == 0 {
+                return Ok(first as char);
+            }
 
-        let remain = if first & 0b1110_0000 == 0b1100_0000 {
-            1
-        } else if first & 0b1111_0000 == 0b1110_0000 {
-            2
-        } else /*if first & 0b1111_1000 == 0b1111_0000*/ {
-            3
-        };
+            state.bytes[0] = first;
+            state.cursor = 1;
+            state.len = if first & 0b1110_0000 == 0b1100_0000 {
+                2
+            } else if first & 0b1111_0000 == 0b1110_0000 {
+                3
+            } else /*if first & 0b1111_1000 == 0b1111_0000*/ {
+                4
+            };
+        }
 
-        for n in 1..=remain {
-            bytes[n] = read_byte()?;
+        let len = state.len;
+
+        while state.cursor < len {
+            let b = read_byte(deadline)?;
+            state.bytes[state.cursor] = b;
+            state.cursor += 1;
         }
 
-        std::str::from_utf8(&bytes[..=remain])
+        let rv = std::str::from_utf8(&state.bytes[..=len])
             .map(|s| s.chars().nth(0).unwrap())
-            .map_err(|e| io::Error::new(io::ErrorKind::InvalidData, e))
+            .map_err(|e| Fault::IOError(io::Error::new(io::ErrorKind::InvalidData, e)));
+
+        state.cursor = 0;
+        state.len = 0;
+
+        rv
     }
 }
 
@@ -183,35 +252,47 @@ impl CrsnExtension for StdioOps {
     fn read_obj(&self, state: &mut RunState, handle: Value)
                 -> Result<Option<Value>, Fault>
     {
+        let deadline = state.cr_deadline;
+
         if handle == self.hdl_stdin {
-            match console::read_char() {
+            match console::read_char(deadline) {
                 Ok(c) => {
                     return Ok(Some(c as Value));
                 }
-                Err(e) => {
+                Err(Fault::IOError(e)) => {
+                    if e.kind() == io::ErrorKind::TimedOut {
+                        return Err(Fault::Blocked);
+                    }
+
                     state.set_flag(Flag::Invalid, true);
                     if e.kind() != io::ErrorKind::InvalidData {
                         state.set_flag(Flag::Eof, true);
                     }
                     return Ok(Some(0));
                 }
+                Err(other) => {
+                    return Err(other);
+                }
             }
-        }
-
-        if handle == self.hdl_stdin_raw {
-            match console::read_byte() {
+        } else if handle == self.hdl_stdin_raw {
+            match console::read_byte(deadline) {
                 Ok(b) => {
                     return Ok(Some(b as Value));
                 }
-                Err(_e) => {
+                Err(Fault::IOError(e)) => {
+                    if e.kind() == io::ErrorKind::TimedOut {
+                        return Err(Fault::Blocked);
+                    }
+
                     state.set_flag(Flag::Invalid, true);
                     state.set_flag(Flag::Eof, true);
                     return Ok(Some(0));
                 }
+                Err(other) => {
+                    return Err(other);
+                }
             }
-        }
-
-        if handle == self.hdl_stdout || handle == self.hdl_stdout_raw {
+        } else if handle == self.hdl_stdout || handle == self.hdl_stdout_raw {
             state.set_flag(Flag::Invalid, true);
             return Ok(Some(0));
         }
@@ -254,13 +335,15 @@ impl CrsnExtension for StdioOps {
     fn read_obj_all(&self, state: &mut RunState, whandle: Wr, rhandle: Value)
                     -> Result<Option<()>, Fault>
     {
+        // XXX This is blocking, there is no sensible way to split it up.
+
         if rhandle == self.hdl_stdin {
             loop {
-                match console::read_char() {
+                match console::read_char(None) {
                     Ok(c) => {
                         state.write(whandle, c as Value)?;
                     }
-                    Err(e) => {
+                    Err(Fault::IOError(e)) => {
                         if e.kind() != io::ErrorKind::InvalidData {
                             state.set_flag(Flag::Eof, true);
                         } else {
@@ -268,17 +351,20 @@ impl CrsnExtension for StdioOps {
                         }
                         return Ok(Some(()));
                     }
+                    Err(other) => {
+                        return Err(other);
+                    }
                 }
             }
         }
 
         if rhandle == self.hdl_stdin_raw {
             loop {
-                match console::read_byte() {
+                match console::read_byte(None) {
                     Ok(c) => {
                         state.write(whandle, c as Value)?;
                     }
-                    Err(e) => {
+                    Err(Fault::IOError(e)) => {
                         if e.kind() != io::ErrorKind::InvalidData {
                             state.set_flag(Flag::Eof, true);
                         } else {
@@ -286,6 +372,9 @@ impl CrsnExtension for StdioOps {
                         }
                         return Ok(Some(()));
                     }
+                    Err(other) => {
+                        return Err(other);
+                    }
                 }
             }
         }

examples/coroutines3-crit.csn

@@ -0,0 +1,44 @@
+(
+    ; This example shows the use of critical sections.
+
+    ; Set short timeslice (50us) to make the effect more pronounced
+    (rt-opt RT_TIMESLICE 50)
+
+    (spawn _ unsafe 'A' 'Z')
+    (spawn _ unsafe 'a' 'z')
+    (spawn _ safe '0' '9') ; Notice that the sequence 0-9 is always printed in its entirety - because it is in a critical section
+    (msleep 200)
+    (halt)
+
+    (proc unsafe start end
+        ; This can be interrupted any time
+        (:x)
+        (yield)
+        (ld r0 start)
+        (:l)
+            (ld @cout r0)
+            (cmp r0 end)
+            (j.eq :x)
+            (inc r0)
+            (j :l)
+    )
+
+    (proc safe start end
+        (:again)
+        (ld r0 start)
+        ; The sequence will always be complete
+        (crit
+            (ld @cout ' ') ; space to make it easier to read
+            (:l)
+                (ld @cout r0)
+                (cmp r0 end)
+                (j.eq :x)
+                (inc r0)
+                (j :l)
+            (:x)
+            (ld @cout ' ') ; space to make it easier to read
+        )
+        (yield)
+        (j :again)
+    )
+)

examples/coroutines4-io.csn

@@ -0,0 +1,17 @@
+(
+    ; This demo shows that stdin is nearly non-blocking
+
+    (spawn _ ReadAndEcho)
+
+    (:a)
+    (mslp 2500)
+    (lds @cout "Tick\n")
+    (j :a)
+
+    (proc ReadAndEcho
+        (:a)
+        (ld @cout '?')
+        (ld @cout @cin)
+        (j :a)
+    )
+)

examples/include/main.csn

@@ -0,0 +1,18 @@
+(
+    (include other)
+    (def BAR (=add FOO 1000))
+
+    (cmp BAR 1123 (ne? (fault)))
+
+    (include utils/itoa.csn)
+    (include "utils/printnum")
+
+    (mkbf r0)
+    (call itoa r0 BAR)
+    (lds @cout @r0)
+    (del @r0)
+    (ld @cout '\n')
+
+    (call printnum BAR)
+    (ld @cout '\n')
+)

examples/include/other.csn

@@ -0,0 +1,3 @@
+(
+    (def FOO 123)
+)

examples/include/utils/itoa.csn

@@ -0,0 +1,14 @@
+(
+    (proc itoa buf num
+        (ld r1 num)
+        (tst r1 (<0? (mul r1 -1)))
+        (:next)
+            (mod r0 r1 10)
+            (add r0 '0')
+            (bfrpush @buf r0)
+            (div r1 10 (z?
+                (tst num (<0? (bfrpush @buf '-')))
+                (ret)))
+            (j :next)
+    )
+)

examples/include/utils/printnum.csn

@@ -0,0 +1,17 @@
+(
+    (proc printnum num
+        (mkbf r15)
+        (ld r1 num)
+        (tst r1 (<0? (mul r1 -1)))
+        (:next)
+            (mod r0 r1 10)
+            (add r0 '0')
+            (bfrpush @r15 r0)
+            (div r1 10 (z?
+                (tst num (<0? (bfrpush @r15 '-')))
+                (lds @cout @r15)
+                (del @r15)
+                (ret)))
+            (j :next)
+    )
+)

examples/loop.csn

@@ -0,0 +1,43 @@
+(
+    ; Unlabeled loop. Can be exited by jumping out
+
+    (loop
+        (nop)
+        (nop)
+        (nop)
+    )
+
+    (barrier)
+
+    ; The above is equivalent to:
+
+    (:label)
+    (nop)
+    (nop)
+    (nop)
+    (j :label)
+
+    (barrier)
+
+    ; The label name can be specified.
+    ; This adds a start label and ":label-end" at the end of the loop:
+
+    (loop :repeat
+        (nop)
+        (nop)
+        (j :repeat-end)
+        (nop)
+    )
+
+    (barrier)
+
+    ; The above is equivalent to: (labels changed to avoid a compile error)
+
+    (:repeat2)
+    (nop)
+    (nop)
+    (j :repeat2-end)
+    (nop)
+    (j :repeat2)
+    (:repeat2-end)
+)

launcher/src/main.rs

@@ -17,7 +17,6 @@ use crsn_screen::ScreenOps;
 use crsn_stdio::StdioOps;
 use crsn_buf::BufOps;
 
-mod read_file;
 mod serde_duration_millis;
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -108,6 +107,14 @@ impl AppConfig for Config {
                     .help("Cycle time (us, append \"s\" or \"ms\" for coarser time)")
                     .takes_value(true),
             )
+            .arg(
+                clap::Arg::with_name("sched")
+                    .long("sched")
+                    .short("S")
+                    .value_name("MILLIS")
+                    .help("Scheduler switch time (ms, append \"u\", \"s\" or \"ms\" for other unit)")
+                    .takes_value(true),
+            )
     }
 
     fn configure(mut self, clap: &ArgMatches) -> anyhow::Result<Self> {
@@ -126,11 +133,28 @@ impl AppConfig for Config {
             } else if t.ends_with("s") {
                 (&t[..(t.len()-1)], 1000_000)
             } else {
-                (t, 1)
+                (t, 1) // us default
             };
 
             self.cycle_time = Duration::from_micros(t.parse::<u64>().expect("parse -C value") * mul);
-            println!("ct = {:?}", self.cycle_time);
+        }
+
+        if let Some(t) = clap.value_of("sched") {
+            let (t, mul) = if t.ends_with("us") {
+                (&t[..(t.len()-2)], 1)
+            } else if t.ends_with("ms") {
+                (&t[..(t.len()-2)], 1000)
+            } else if t.ends_with("m") {
+                (&t[..(t.len()-1)], 1000)
+            } else if t.ends_with("u") {
+                (&t[..(t.len()-1)], 1)
+            } else if t.ends_with("s") {
+                (&t[..(t.len()-1)], 1000_000)
+            } else {
+                (t, 1000) // ms default
+            };
+
+            self.switch_time = Duration::from_micros(t.parse::<u64>().expect("parse -S value") * mul);
         }
         Ok(self)
     }
@@ -142,11 +166,9 @@ fn main() -> anyhow::Result<()> {
 
     debug!("Loading {}", config.program_file);
 
-    let source = read_file::read_file(&config.program_file)?;
-
     let uniq = CrsnUniq::new();
 
-    let parsed = crsn::asm::assemble(&source, &uniq, vec![
+    let parsed = crsn::asm::assemble(&config.program_file, &uniq, vec![
         ArithOps::new(),
         BufOps::new(),
         ScreenOps::new(),